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linux-7.2.3/drivers/w1/masters/Kconfig

@@ -0,0 +1,92 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# 1-wire bus master configuration
+#
+
+menu "1-wire Bus Masters"
+
+config W1_MASTER_AMD_AXI
+	tristate "AMD AXI 1-wire bus host"
+	help
+	  Say Y here is you want to support the AMD AXI 1-wire IP core.
+	  This driver makes use of the programmable logic IP to perform
+	  correctly timed 1 wire transactions without relying on GPIO timing
+	  through the kernel.
+
+	  This driver can also be built as a module.  If so, the module will be
+	  called amd_w1_axi.
+
+config W1_MASTER_MATROX
+	tristate "Matrox G400 transport layer for 1-wire"
+	depends on PCI
+	help
+	  Say Y here if you want to communicate with your 1-wire devices
+	  using Matrox's G400 GPIO pins.
+
+	  This support is also available as a module.  If so, the module
+	  will be called matrox_w1.
+
+config W1_MASTER_DS2490
+	tristate "DS2490 USB <-> W1 transport layer for 1-wire"
+  	depends on USB
+  	help
+	  Say Y here if you want to have a driver for DS2490 based USB <-> W1 bridges,
+	  for example DS9490*.
+
+  	  This support is also available as a module.  If so, the module
+	  will be called ds2490.
+
+config W1_MASTER_DS2482
+	tristate "Maxim DS2482 I2C to 1-Wire bridge"
+	depends on I2C
+	help
+	  If you say yes here you get support for the Maxim DS2482
+	  I2C to 1-Wire bridge.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called ds2482.
+
+config W1_MASTER_MXC
+	tristate "Freescale MXC 1-wire busmaster"
+	depends on ARCH_MXC || COMPILE_TEST
+	help
+	  Say Y here to enable MXC 1-wire host
+
+config W1_MASTER_GPIO
+	tristate "GPIO 1-wire busmaster"
+	depends on GPIOLIB || COMPILE_TEST
+	help
+	  Say Y here if you want to communicate with your 1-wire devices using
+	  GPIO pins. This driver uses the GPIO API to control the wire.
+
+	  This support is also available as a module.  If so, the module
+	  will be called w1-gpio.
+
+config HDQ_MASTER_OMAP
+	tristate "OMAP HDQ driver"
+	depends on ARCH_OMAP || COMPILE_TEST
+	help
+	  Say Y here if you want support for the 1-wire or HDQ Interface
+	  on an OMAP processor.
+
+config W1_MASTER_SGI
+	tristate "SGI ASIC driver"
+	help
+	  Say Y here if you want support for your 1-wire devices using
+	  SGI ASIC 1-Wire interface
+
+	  This support is also available as a module.  If so, the module
+	  will be called sgi_w1.
+
+config W1_MASTER_UART
+	tristate "UART 1-wire driver"
+	depends on SERIAL_DEV_BUS
+	help
+	  Say Y here if you want to communicate with your 1-wire devices using
+	  UART interface.
+
+	  This support is also available as a module.  If so, the module
+	  will be called w1-uart.
+
+endmenu
+

linux-7.2.3/drivers/w1/masters/Makefile

@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for 1-wire bus master drivers.
+#
+
+obj-$(CONFIG_W1_MASTER_AMD_AXI)		+= amd_axi_w1.o
+obj-$(CONFIG_W1_MASTER_MATROX)		+= matrox_w1.o
+obj-$(CONFIG_W1_MASTER_DS2490)		+= ds2490.o
+obj-$(CONFIG_W1_MASTER_DS2482)		+= ds2482.o
+obj-$(CONFIG_W1_MASTER_MXC)		+= mxc_w1.o
+
+obj-$(CONFIG_W1_MASTER_GPIO)		+= w1-gpio.o
+obj-$(CONFIG_HDQ_MASTER_OMAP)		+= omap_hdq.o
+obj-$(CONFIG_W1_MASTER_SGI)		+= sgi_w1.o
+obj-$(CONFIG_W1_MASTER_UART)		+= w1-uart.o

linux-7.2.3/drivers/w1/masters/amd_axi_w1.c

@@ -0,0 +1,395 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * amd_axi_w1 - AMD 1Wire programmable logic bus host driver
+ *
+ * Copyright (C) 2022-2023 Advanced Micro Devices, Inc. All Rights Reserved.
+ */
+
+#include <linux/atomic.h>
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#include <linux/w1.h>
+
+/* 1-wire AMD IP definition */
+#define AXIW1_IPID	0x10ee4453
+/* Registers offset */
+#define AXIW1_INST_REG	0x0
+#define AXIW1_CTRL_REG	0x4
+#define AXIW1_IRQE_REG	0x8
+#define AXIW1_STAT_REG	0xC
+#define AXIW1_DATA_REG	0x10
+#define AXIW1_IPVER_REG	0x18
+#define AXIW1_IPID_REG	0x1C
+/* Instructions */
+#define AXIW1_INITPRES	0x0800
+#define AXIW1_READBIT	0x0C00
+#define AXIW1_WRITEBIT	0x0E00
+#define AXIW1_READBYTE	0x0D00
+#define AXIW1_WRITEBYTE	0x0F00
+/* Status flag masks */
+#define AXIW1_DONE	BIT(0)
+#define AXIW1_READY	BIT(4)
+#define AXIW1_PRESENCE	BIT(31)
+#define AXIW1_MAJORVER_MASK	GENMASK(23, 8)
+#define AXIW1_MINORVER_MASK	GENMASK(7, 0)
+/* Control flag */
+#define AXIW1_GO	BIT(0)
+#define AXI_CLEAR	0
+#define AXI_RESET	BIT(31)
+#define AXIW1_READDATA	BIT(0)
+/* Interrupt Enable */
+#define AXIW1_READY_IRQ_EN	BIT(4)
+#define AXIW1_DONE_IRQ_EN	BIT(0)
+
+#define AXIW1_TIMEOUT	msecs_to_jiffies(100)
+
+#define DRIVER_NAME	"amd_axi_w1"
+
+struct amd_axi_w1_local {
+	struct device *dev;
+	void __iomem *base_addr;
+	int irq;
+	atomic_t flag;			/* Set on IRQ, cleared once serviced */
+	wait_queue_head_t wait_queue;
+	struct w1_bus_master bus_host;
+};
+
+/**
+ * amd_axi_w1_wait_irq_interruptible_timeout() - Wait for IRQ with timeout.
+ *
+ * @amd_axi_w1_local:	Pointer to device structure
+ * @IRQ:		IRQ channel to wait on
+ *
+ * Return:		%0 - OK, %-EINTR - Interrupted, %-EBUSY - Timed out
+ */
+static int amd_axi_w1_wait_irq_interruptible_timeout(struct amd_axi_w1_local *amd_axi_w1_local,
+						     u32 IRQ)
+{
+	int ret;
+
+	/* Enable the IRQ requested and wait for flag to indicate it's been triggered */
+	iowrite32(IRQ, amd_axi_w1_local->base_addr + AXIW1_IRQE_REG);
+	ret = wait_event_interruptible_timeout(amd_axi_w1_local->wait_queue,
+					       atomic_read(&amd_axi_w1_local->flag) != 0,
+					       AXIW1_TIMEOUT);
+	if (ret < 0) {
+		dev_err(amd_axi_w1_local->dev, "Wait IRQ Interrupted\n");
+		return -EINTR;
+	}
+
+	if (!ret) {
+		dev_err(amd_axi_w1_local->dev, "Wait IRQ Timeout\n");
+		return -EBUSY;
+	}
+
+	atomic_set(&amd_axi_w1_local->flag, 0);
+	return 0;
+}
+
+/**
+ * amd_axi_w1_touch_bit() - Performs the touch-bit function - write a 0 or 1 and reads the level.
+ *
+ * @data:	Pointer to device structure
+ * @bit:	The level to write
+ *
+ * Return:	The level read
+ */
+static u8 amd_axi_w1_touch_bit(void *data, u8 bit)
+{
+	struct amd_axi_w1_local *amd_axi_w1_local = data;
+	u8 val = 0;
+	int rc;
+
+	/* Wait for READY signal to be 1 to ensure 1-wire IP is ready */
+	while ((ioread32(amd_axi_w1_local->base_addr + AXIW1_STAT_REG) & AXIW1_READY) == 0) {
+		rc = amd_axi_w1_wait_irq_interruptible_timeout(amd_axi_w1_local,
+							       AXIW1_READY_IRQ_EN);
+		if (rc < 0)
+			return 1; /* Callee doesn't test for error. Return inactive bus state */
+	}
+
+	if (bit)
+		/* Read. Write read Bit command in register 0 */
+		iowrite32(AXIW1_READBIT, amd_axi_w1_local->base_addr + AXIW1_INST_REG);
+	else
+		/* Write. Write tx Bit command in instruction register with bit to transmit */
+		iowrite32(AXIW1_WRITEBIT + (bit & 0x01),
+			  amd_axi_w1_local->base_addr + AXIW1_INST_REG);
+
+	/* Write Go signal and clear control reset signal in control register */
+	iowrite32(AXIW1_GO, amd_axi_w1_local->base_addr + AXIW1_CTRL_REG);
+
+	/* Wait for done signal to be 1 */
+	while ((ioread32(amd_axi_w1_local->base_addr + AXIW1_STAT_REG) & AXIW1_DONE) != 1) {
+		rc = amd_axi_w1_wait_irq_interruptible_timeout(amd_axi_w1_local, AXIW1_DONE_IRQ_EN);
+		if (rc < 0)
+			return 1; /* Callee doesn't test for error. Return inactive bus state */
+	}
+
+	/* If read, Retrieve data from register */
+	if (bit)
+		val = (u8)(ioread32(amd_axi_w1_local->base_addr + AXIW1_DATA_REG) & AXIW1_READDATA);
+
+	/* Clear Go signal in register 1 */
+	iowrite32(AXI_CLEAR, amd_axi_w1_local->base_addr + AXIW1_CTRL_REG);
+
+	return val;
+}
+
+/**
+ * amd_axi_w1_read_byte - Performs the read byte function.
+ *
+ * @data:	Pointer to device structure
+ * Return:	The value read
+ */
+static u8 amd_axi_w1_read_byte(void *data)
+{
+	struct amd_axi_w1_local *amd_axi_w1_local = data;
+	u8 val = 0;
+	int rc;
+
+	/* Wait for READY signal to be 1 to ensure 1-wire IP is ready */
+	while ((ioread32(amd_axi_w1_local->base_addr + AXIW1_STAT_REG) & AXIW1_READY) == 0) {
+		rc = amd_axi_w1_wait_irq_interruptible_timeout(amd_axi_w1_local,
+							       AXIW1_READY_IRQ_EN);
+		if (rc < 0)
+			return 0xFF; /* Return inactive bus state */
+	}
+
+	/* Write read Byte command in instruction register*/
+	iowrite32(AXIW1_READBYTE, amd_axi_w1_local->base_addr + AXIW1_INST_REG);
+
+	/* Write Go signal and clear control reset signal in control register */
+	iowrite32(AXIW1_GO, amd_axi_w1_local->base_addr + AXIW1_CTRL_REG);
+
+	/* Wait for done signal to be 1 */
+	while ((ioread32(amd_axi_w1_local->base_addr + AXIW1_STAT_REG) & AXIW1_DONE) != 1) {
+		rc = amd_axi_w1_wait_irq_interruptible_timeout(amd_axi_w1_local, AXIW1_DONE_IRQ_EN);
+		if (rc < 0)
+			return 0xFF; /* Return inactive bus state */
+	}
+
+	/* Retrieve LSB bit in data register to get RX byte */
+	val = (u8)(ioread32(amd_axi_w1_local->base_addr + AXIW1_DATA_REG) & 0x000000FF);
+
+	/* Clear Go signal in control register */
+	iowrite32(AXI_CLEAR, amd_axi_w1_local->base_addr + AXIW1_CTRL_REG);
+
+	return val;
+}
+
+/**
+ * amd_axi_w1_write_byte - Performs the write byte function.
+ *
+ * @data:	The ds2482 channel pointer
+ * @val:	The value to write
+ */
+static void amd_axi_w1_write_byte(void *data, u8 val)
+{
+	struct amd_axi_w1_local *amd_axi_w1_local = data;
+	int rc;
+
+	/* Wait for READY signal to be 1 to ensure 1-wire IP is ready */
+	while ((ioread32(amd_axi_w1_local->base_addr + AXIW1_STAT_REG) & AXIW1_READY) == 0) {
+		rc = amd_axi_w1_wait_irq_interruptible_timeout(amd_axi_w1_local,
+							       AXIW1_READY_IRQ_EN);
+		if (rc < 0)
+			return;
+	}
+
+	/* Write tx Byte command in instruction register with bit to transmit */
+	iowrite32(AXIW1_WRITEBYTE + val, amd_axi_w1_local->base_addr + AXIW1_INST_REG);
+
+	/* Write Go signal and clear control reset signal in register 1 */
+	iowrite32(AXIW1_GO, amd_axi_w1_local->base_addr + AXIW1_CTRL_REG);
+
+	/* Wait for done signal to be 1 */
+	while ((ioread32(amd_axi_w1_local->base_addr + AXIW1_STAT_REG) & AXIW1_DONE) != 1) {
+		rc = amd_axi_w1_wait_irq_interruptible_timeout(amd_axi_w1_local,
+							       AXIW1_DONE_IRQ_EN);
+		if (rc < 0)
+			return;
+	}
+
+	/* Clear Go signal in control register */
+	iowrite32(AXI_CLEAR, amd_axi_w1_local->base_addr + AXIW1_CTRL_REG);
+}
+
+/**
+ * amd_axi_w1_reset_bus() - Issues a reset bus sequence.
+ *
+ * @data:	the bus host data struct
+ * Return:	0=Device present, 1=No device present or error
+ */
+static u8 amd_axi_w1_reset_bus(void *data)
+{
+	struct amd_axi_w1_local *amd_axi_w1_local = data;
+	u8 val = 0;
+	int rc;
+
+	/* Reset 1-wire Axi IP */
+	iowrite32(AXI_RESET, amd_axi_w1_local->base_addr + AXIW1_CTRL_REG);
+
+	/* Wait for READY signal to be 1 to ensure 1-wire IP is ready */
+	while ((ioread32(amd_axi_w1_local->base_addr + AXIW1_STAT_REG) & AXIW1_READY) == 0) {
+		rc = amd_axi_w1_wait_irq_interruptible_timeout(amd_axi_w1_local,
+							       AXIW1_READY_IRQ_EN);
+		if (rc < 0)
+			return 1; /* Something went wrong with the hardware */
+	}
+	/* Write Initialization command in instruction register */
+	iowrite32(AXIW1_INITPRES, amd_axi_w1_local->base_addr + AXIW1_INST_REG);
+
+	/* Write Go signal and clear control reset signal in register 1 */
+	iowrite32(AXIW1_GO, amd_axi_w1_local->base_addr + AXIW1_CTRL_REG);
+
+	/* Wait for done signal to be 1 */
+	while ((ioread32(amd_axi_w1_local->base_addr + AXIW1_STAT_REG) & AXIW1_DONE) != 1) {
+		rc = amd_axi_w1_wait_irq_interruptible_timeout(amd_axi_w1_local, AXIW1_DONE_IRQ_EN);
+		if (rc < 0)
+			return 1; /* Something went wrong with the hardware */
+	}
+	/* Retrieve MSB bit in status register to get failure bit */
+	if ((ioread32(amd_axi_w1_local->base_addr + AXIW1_STAT_REG) & AXIW1_PRESENCE) != 0)
+		val = 1;
+
+	/* Clear Go signal in control register */
+	iowrite32(AXI_CLEAR, amd_axi_w1_local->base_addr + AXIW1_CTRL_REG);
+
+	return val;
+}
+
+/* Reset the 1-wire AXI IP. Put the IP in reset state and clear registers */
+static void amd_axi_w1_reset(struct amd_axi_w1_local *amd_axi_w1_local)
+{
+	iowrite32(AXI_RESET, amd_axi_w1_local->base_addr + AXIW1_CTRL_REG);
+	iowrite32(AXI_CLEAR, amd_axi_w1_local->base_addr + AXIW1_INST_REG);
+	iowrite32(AXI_CLEAR, amd_axi_w1_local->base_addr + AXIW1_IRQE_REG);
+	iowrite32(AXI_CLEAR, amd_axi_w1_local->base_addr + AXIW1_STAT_REG);
+	iowrite32(AXI_CLEAR, amd_axi_w1_local->base_addr + AXIW1_DATA_REG);
+}
+
+static irqreturn_t amd_axi_w1_irq(int irq, void *lp)
+{
+	struct amd_axi_w1_local *amd_axi_w1_local = lp;
+
+	/* Reset interrupt trigger */
+	iowrite32(AXI_CLEAR, amd_axi_w1_local->base_addr + AXIW1_IRQE_REG);
+
+	atomic_set(&amd_axi_w1_local->flag, 1);
+	wake_up_interruptible(&amd_axi_w1_local->wait_queue);
+
+	return IRQ_HANDLED;
+}
+
+static int amd_axi_w1_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct amd_axi_w1_local *lp;
+	struct clk *clk;
+	u32 ver_major, ver_minor;
+	int val, rc = 0;
+
+	lp = devm_kzalloc(dev, sizeof(*lp), GFP_KERNEL);
+	if (!lp)
+		return -ENOMEM;
+
+	lp->dev = dev;
+	lp->base_addr = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(lp->base_addr))
+		return PTR_ERR(lp->base_addr);
+
+	lp->irq = platform_get_irq(pdev, 0);
+	if (lp->irq < 0)
+		return lp->irq;
+
+	rc = devm_request_irq(dev, lp->irq, &amd_axi_w1_irq, IRQF_TRIGGER_HIGH, DRIVER_NAME, lp);
+	if (rc)
+		return rc;
+
+	/* Initialize wait queue and flag */
+	init_waitqueue_head(&lp->wait_queue);
+
+	clk = devm_clk_get_enabled(dev, NULL);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	/* Verify IP presence in HW */
+	if (ioread32(lp->base_addr + AXIW1_IPID_REG) != AXIW1_IPID) {
+		dev_err(dev, "AMD 1-wire IP not detected in hardware\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * Allow for future driver expansion supporting new hardware features
+	 * This driver currently only supports hardware 1.x, but include logic
+	 * to detect if a potentially incompatible future version is used
+	 * by reading major version ID. It is highly undesirable for new IP versions
+	 * to break the API, but this code will at least allow for graceful failure
+	 * should that happen. Future new features can be enabled by hardware
+	 * incrementing the minor version and augmenting the driver to detect capability
+	 * using the minor version number
+	 */
+	val = ioread32(lp->base_addr + AXIW1_IPVER_REG);
+	ver_major = FIELD_GET(AXIW1_MAJORVER_MASK, val);
+	ver_minor = FIELD_GET(AXIW1_MINORVER_MASK, val);
+
+	if (ver_major != 1) {
+		dev_err(dev, "AMD AXI W1 host version %u.%u is not supported by this driver",
+			ver_major, ver_minor);
+		return -ENODEV;
+	}
+
+	lp->bus_host.data = lp;
+	lp->bus_host.touch_bit = amd_axi_w1_touch_bit;
+	lp->bus_host.read_byte = amd_axi_w1_read_byte;
+	lp->bus_host.write_byte = amd_axi_w1_write_byte;
+	lp->bus_host.reset_bus = amd_axi_w1_reset_bus;
+
+	amd_axi_w1_reset(lp);
+
+	platform_set_drvdata(pdev, lp);
+	rc = w1_add_master_device(&lp->bus_host);
+	if (rc) {
+		dev_err(dev, "Could not add host device\n");
+		return rc;
+	}
+
+	return 0;
+}
+
+static void amd_axi_w1_remove(struct platform_device *pdev)
+{
+	struct amd_axi_w1_local *lp = platform_get_drvdata(pdev);
+
+	w1_remove_master_device(&lp->bus_host);
+}
+
+static const struct of_device_id amd_axi_w1_of_match[] = {
+	{ .compatible = "amd,axi-1wire-host" },
+	{ /* end of list */ },
+};
+MODULE_DEVICE_TABLE(of, amd_axi_w1_of_match);
+
+static struct platform_driver amd_axi_w1_driver = {
+	.probe = amd_axi_w1_probe,
+	.remove = amd_axi_w1_remove,
+	.driver = {
+		.name = DRIVER_NAME,
+		.of_match_table = amd_axi_w1_of_match,
+	},
+};
+module_platform_driver(amd_axi_w1_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Kris Chaplin <kris.chaplin@amd.com>");
+MODULE_DESCRIPTION("Driver for AMD AXI 1 Wire IP core");

linux-7.2.3/drivers/w1/masters/ds2482.c

@@ -0,0 +1,561 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ds2482.c - provides i2c to w1-master bridge(s)
+ * Copyright (C) 2005  Ben Gardner <bgardner@wabtec.com>
+ *
+ * The DS2482 is a sensor chip made by Dallas Semiconductor (Maxim).
+ * It is a I2C to 1-wire bridge.
+ * There are two variations: -100 and -800, which have 1 or 8 1-wire ports.
+ * The complete datasheet can be obtained from MAXIM's website at:
+ *   https://www.analog.com/en/products/ds2482-100.html
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/regulator/consumer.h>
+
+#include <linux/w1.h>
+
+/*
+ * Allow the active pullup to be disabled, default is enabled.
+ *
+ * Note from the DS2482 datasheet:
+ * The APU bit controls whether an active pullup (controlled slew-rate
+ * transistor) or a passive pullup (Rwpu resistor) will be used to drive
+ * a 1-Wire line from low to high. When APU = 0, active pullup is disabled
+ * (resistor mode). Active Pullup should always be selected unless there is
+ * only a single slave on the 1-Wire line.
+ */
+static int ds2482_active_pullup = 1;
+module_param_named(active_pullup, ds2482_active_pullup, int, 0644);
+MODULE_PARM_DESC(active_pullup, "Active pullup (apply to all buses): " \
+				"0-disable, 1-enable (default)");
+
+/* extra configurations - e.g. 1WS */
+static int extra_config;
+module_param(extra_config, int, 0644);
+MODULE_PARM_DESC(extra_config, "Extra Configuration settings 1=APU,2=PPM,3=SPU,8=1WS");
+
+/*
+ * The DS2482 registers - there are 3 registers that are addressed by a read
+ * pointer. The read pointer is set by the last command executed.
+ *
+ * To read the data, issue a register read for any address
+ */
+#define DS2482_CMD_RESET		0xF0	/* No param */
+#define DS2482_CMD_SET_READ_PTR		0xE1	/* Param: DS2482_PTR_CODE_xxx */
+#define DS2482_CMD_CHANNEL_SELECT	0xC3	/* Param: Channel byte - DS2482-800 only */
+#define DS2482_CMD_WRITE_CONFIG		0xD2	/* Param: Config byte */
+#define DS2482_CMD_1WIRE_RESET		0xB4	/* Param: None */
+#define DS2482_CMD_1WIRE_SINGLE_BIT	0x87	/* Param: Bit byte (bit7) */
+#define DS2482_CMD_1WIRE_WRITE_BYTE	0xA5	/* Param: Data byte */
+#define DS2482_CMD_1WIRE_READ_BYTE	0x96	/* Param: None */
+/* Note to read the byte, Set the ReadPtr to Data then read (any addr) */
+#define DS2482_CMD_1WIRE_TRIPLET	0x78	/* Param: Dir byte (bit7) */
+
+/* Values for DS2482_CMD_SET_READ_PTR */
+#define DS2482_PTR_CODE_STATUS		0xF0
+#define DS2482_PTR_CODE_DATA		0xE1
+#define DS2482_PTR_CODE_CHANNEL		0xD2	/* DS2482-800 only */
+#define DS2482_PTR_CODE_CONFIG		0xC3
+
+/*
+ * Configure Register bit definitions
+ * The top 4 bits always read 0.
+ * To write, the top nibble must be the 1's compl. of the low nibble.
+ */
+#define DS2482_REG_CFG_1WS		0x08	/* 1-wire speed */
+#define DS2482_REG_CFG_SPU		0x04	/* strong pull-up */
+#define DS2482_REG_CFG_PPM		0x02	/* presence pulse masking */
+#define DS2482_REG_CFG_APU		0x01	/* active pull-up */
+
+
+/*
+ * Write and verify codes for the CHANNEL_SELECT command (DS2482-800 only).
+ * To set the channel, write the value at the index of the channel.
+ * Read and compare against the corresponding value to verify the change.
+ */
+static const u8 ds2482_chan_wr[8] = { 0xF0, 0xE1, 0xD2, 0xC3, 0xB4, 0xA5, 0x96, 0x87 };
+static const u8 ds2482_chan_rd[8] = { 0xB8, 0xB1, 0xAA, 0xA3, 0x9C, 0x95, 0x8E, 0x87 };
+
+
+/*
+ * Status Register bit definitions (read only)
+ */
+#define DS2482_REG_STS_DIR		0x80
+#define DS2482_REG_STS_TSB		0x40
+#define DS2482_REG_STS_SBR		0x20
+#define DS2482_REG_STS_RST		0x10
+#define DS2482_REG_STS_LL		0x08
+#define DS2482_REG_STS_SD		0x04
+#define DS2482_REG_STS_PPD		0x02
+#define DS2482_REG_STS_1WB		0x01
+
+/*
+ * Client data (each client gets its own)
+ */
+
+struct ds2482_data;
+
+struct ds2482_w1_chan {
+	struct ds2482_data	*pdev;
+	u8			channel;
+	struct w1_bus_master	w1_bm;
+};
+
+struct ds2482_data {
+	struct i2c_client	*client;
+	struct mutex		access_lock;
+
+	/* 1-wire interface(s) */
+	int			w1_count;	/* 1 or 8 */
+	struct ds2482_w1_chan	w1_ch[8];
+
+	/* per-device values */
+	u8			channel;
+	u8			read_prt;	/* see DS2482_PTR_CODE_xxx */
+	u8			reg_config;
+};
+
+
+/**
+ * ds2482_calculate_config - Helper to calculate values for configuration register
+ * @conf: the raw config value
+ * Return: the value w/ complements that can be written to register
+ */
+static inline u8 ds2482_calculate_config(u8 conf)
+{
+	conf |= extra_config;
+
+	if (ds2482_active_pullup)
+		conf |= DS2482_REG_CFG_APU;
+
+	return conf | ((~conf & 0x0f) << 4);
+}
+
+
+/**
+ * ds2482_select_register - Sets the read pointer.
+ * @pdev:		The ds2482 client pointer
+ * @read_ptr:	see DS2482_PTR_CODE_xxx above
+ * Return: -1 on failure, 0 on success
+ */
+static inline int ds2482_select_register(struct ds2482_data *pdev, u8 read_ptr)
+{
+	if (pdev->read_prt != read_ptr) {
+		if (i2c_smbus_write_byte_data(pdev->client,
+					      DS2482_CMD_SET_READ_PTR,
+					      read_ptr) < 0)
+			return -1;
+
+		pdev->read_prt = read_ptr;
+	}
+	return 0;
+}
+
+/**
+ * ds2482_send_cmd - Sends a command without a parameter
+ * @pdev:	The ds2482 client pointer
+ * @cmd:	DS2482_CMD_RESET,
+ *		DS2482_CMD_1WIRE_RESET,
+ *		DS2482_CMD_1WIRE_READ_BYTE
+ * Return: -1 on failure, 0 on success
+ */
+static inline int ds2482_send_cmd(struct ds2482_data *pdev, u8 cmd)
+{
+	if (i2c_smbus_write_byte(pdev->client, cmd) < 0)
+		return -1;
+
+	pdev->read_prt = DS2482_PTR_CODE_STATUS;
+	return 0;
+}
+
+/**
+ * ds2482_send_cmd_data - Sends a command with a parameter
+ * @pdev:	The ds2482 client pointer
+ * @cmd:	DS2482_CMD_WRITE_CONFIG,
+ *		DS2482_CMD_1WIRE_SINGLE_BIT,
+ *		DS2482_CMD_1WIRE_WRITE_BYTE,
+ *		DS2482_CMD_1WIRE_TRIPLET
+ * @byte:	The data to send
+ * Return: -1 on failure, 0 on success
+ */
+static inline int ds2482_send_cmd_data(struct ds2482_data *pdev,
+				       u8 cmd, u8 byte)
+{
+	if (i2c_smbus_write_byte_data(pdev->client, cmd, byte) < 0)
+		return -1;
+
+	/* all cmds leave in STATUS, except CONFIG */
+	pdev->read_prt = (cmd != DS2482_CMD_WRITE_CONFIG) ?
+			 DS2482_PTR_CODE_STATUS : DS2482_PTR_CODE_CONFIG;
+	return 0;
+}
+
+
+/*
+ * 1-Wire interface code
+ */
+
+#define DS2482_WAIT_IDLE_TIMEOUT	100
+
+/**
+ * ds2482_wait_1wire_idle - Waits until the 1-wire interface is idle (not busy)
+ *
+ * @pdev: Pointer to the device structure
+ * Return: the last value read from status or -1 (failure)
+ */
+static int ds2482_wait_1wire_idle(struct ds2482_data *pdev)
+{
+	int temp = -1;
+	int retries = 0;
+
+	if (!ds2482_select_register(pdev, DS2482_PTR_CODE_STATUS)) {
+		do {
+			temp = i2c_smbus_read_byte(pdev->client);
+		} while ((temp >= 0) && (temp & DS2482_REG_STS_1WB) &&
+			 (++retries < DS2482_WAIT_IDLE_TIMEOUT));
+	}
+
+	if (retries >= DS2482_WAIT_IDLE_TIMEOUT)
+		pr_err("%s: timeout on channel %d\n",
+		       __func__, pdev->channel);
+
+	return temp;
+}
+
+/**
+ * ds2482_set_channel - Selects a w1 channel.
+ * The 1-wire interface must be idle before calling this function.
+ *
+ * @pdev:		The ds2482 client pointer
+ * @channel:		0-7
+ * Return:		-1 (failure) or 0 (success)
+ */
+static int ds2482_set_channel(struct ds2482_data *pdev, u8 channel)
+{
+	if (i2c_smbus_write_byte_data(pdev->client, DS2482_CMD_CHANNEL_SELECT,
+				      ds2482_chan_wr[channel]) < 0)
+		return -1;
+
+	pdev->read_prt = DS2482_PTR_CODE_CHANNEL;
+	pdev->channel = -1;
+	if (i2c_smbus_read_byte(pdev->client) == ds2482_chan_rd[channel]) {
+		pdev->channel = channel;
+		return 0;
+	}
+	return -1;
+}
+
+
+/**
+ * ds2482_w1_touch_bit - Performs the touch-bit function, which writes a 0 or 1 and reads the level.
+ *
+ * @data:	The ds2482 channel pointer
+ * @bit:	The level to write: 0 or non-zero
+ * Return:	The level read: 0 or 1
+ */
+static u8 ds2482_w1_touch_bit(void *data, u8 bit)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+	int status = -1;
+
+	mutex_lock(&pdev->access_lock);
+
+	/* Select the channel */
+	ds2482_wait_1wire_idle(pdev);
+	if (pdev->w1_count > 1)
+		ds2482_set_channel(pdev, pchan->channel);
+
+	/* Send the touch command, wait until 1WB == 0, return the status */
+	if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_SINGLE_BIT,
+				  bit ? 0xFF : 0))
+		status = ds2482_wait_1wire_idle(pdev);
+
+	mutex_unlock(&pdev->access_lock);
+
+	return (status & DS2482_REG_STS_SBR) ? 1 : 0;
+}
+
+/**
+ * ds2482_w1_triplet - Performs the triplet function, which reads two bits and writes a bit.
+ * The bit written is determined by the two reads:
+ *   00 => dbit, 01 => 0, 10 => 1
+ *
+ * @data:	The ds2482 channel pointer
+ * @dbit:	The direction to choose if both branches are valid
+ * Return:	b0=read1 b1=read2 b3=bit written
+ */
+static u8 ds2482_w1_triplet(void *data, u8 dbit)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+	int status = (3 << 5);
+
+	mutex_lock(&pdev->access_lock);
+
+	/* Select the channel */
+	ds2482_wait_1wire_idle(pdev);
+	if (pdev->w1_count > 1)
+		ds2482_set_channel(pdev, pchan->channel);
+
+	/* Send the triplet command, wait until 1WB == 0, return the status */
+	if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_TRIPLET,
+				  dbit ? 0xFF : 0))
+		status = ds2482_wait_1wire_idle(pdev);
+
+	mutex_unlock(&pdev->access_lock);
+
+	/* Decode the status */
+	return (status >> 5);
+}
+
+/**
+ * ds2482_w1_write_byte - Performs the write byte function.
+ *
+ * @data:	The ds2482 channel pointer
+ * @byte:	The value to write
+ */
+static void ds2482_w1_write_byte(void *data, u8 byte)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+
+	mutex_lock(&pdev->access_lock);
+
+	/* Select the channel */
+	ds2482_wait_1wire_idle(pdev);
+	if (pdev->w1_count > 1)
+		ds2482_set_channel(pdev, pchan->channel);
+
+	/* Send the write byte command */
+	ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_WRITE_BYTE, byte);
+
+	mutex_unlock(&pdev->access_lock);
+}
+
+/**
+ * ds2482_w1_read_byte - Performs the read byte function.
+ *
+ * @data:	The ds2482 channel pointer
+ * Return:	The value read
+ */
+static u8 ds2482_w1_read_byte(void *data)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+	int result;
+
+	mutex_lock(&pdev->access_lock);
+
+	/* Select the channel */
+	ds2482_wait_1wire_idle(pdev);
+	if (pdev->w1_count > 1)
+		ds2482_set_channel(pdev, pchan->channel);
+
+	/* Send the read byte command */
+	ds2482_send_cmd(pdev, DS2482_CMD_1WIRE_READ_BYTE);
+
+	/* Wait until 1WB == 0 */
+	ds2482_wait_1wire_idle(pdev);
+
+	/* Select the data register */
+	ds2482_select_register(pdev, DS2482_PTR_CODE_DATA);
+
+	/* Read the data byte */
+	result = i2c_smbus_read_byte(pdev->client);
+
+	mutex_unlock(&pdev->access_lock);
+
+	return result;
+}
+
+
+/**
+ * ds2482_w1_reset_bus - Sends a reset on the 1-wire interface
+ *
+ * @data:	The ds2482 channel pointer
+ * Return:	0=Device present, 1=No device present or error
+ */
+static u8 ds2482_w1_reset_bus(void *data)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+	int err;
+	u8 retval = 1;
+
+	mutex_lock(&pdev->access_lock);
+
+	/* Select the channel */
+	ds2482_wait_1wire_idle(pdev);
+	if (pdev->w1_count > 1)
+		ds2482_set_channel(pdev, pchan->channel);
+
+	/* Send the reset command */
+	err = ds2482_send_cmd(pdev, DS2482_CMD_1WIRE_RESET);
+	if (err >= 0) {
+		/* Wait until the reset is complete */
+		err = ds2482_wait_1wire_idle(pdev);
+		retval = !(err & DS2482_REG_STS_PPD);
+
+		/* If the chip did reset since detect, re-config it */
+		if (err & DS2482_REG_STS_RST)
+			ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG,
+					     ds2482_calculate_config(0x00));
+	}
+
+	mutex_unlock(&pdev->access_lock);
+
+	return retval;
+}
+
+static u8 ds2482_w1_set_pullup(void *data, int delay)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+	u8 retval = 1;
+
+	/* if delay is non-zero activate the pullup,
+	 * the strong pullup will be automatically deactivated
+	 * by the master, so do not explicitly deactive it
+	 */
+	if (delay) {
+		/* both waits are crucial, otherwise devices might not be
+		 * powered long enough, causing e.g. a w1_therm sensor to
+		 * provide wrong conversion results
+		 */
+		ds2482_wait_1wire_idle(pdev);
+		/* note: it seems like both SPU and APU have to be set! */
+		retval = ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG,
+			ds2482_calculate_config(DS2482_REG_CFG_SPU |
+						DS2482_REG_CFG_APU));
+		ds2482_wait_1wire_idle(pdev);
+	}
+
+	return retval;
+}
+
+
+static int ds2482_probe(struct i2c_client *client)
+{
+	struct ds2482_data *data;
+	int err = -ENODEV;
+	int temp1;
+	int idx;
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
+				     I2C_FUNC_SMBUS_BYTE))
+		return -ENODEV;
+
+	data = devm_kzalloc(&client->dev, sizeof(struct ds2482_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	ret = devm_regulator_get_enable(&client->dev, "vcc");
+	if (ret)
+		return dev_err_probe(&client->dev, ret, "Failed to enable regulator\n");
+
+	data->client = client;
+	i2c_set_clientdata(client, data);
+
+	/* Reset the device (sets the read_ptr to status) */
+	if (ds2482_send_cmd(data, DS2482_CMD_RESET) < 0) {
+		dev_warn(&client->dev, "DS2482 reset failed.\n");
+		return err;
+	}
+
+	/* Sleep at least 525ns to allow the reset to complete */
+	ndelay(525);
+
+	/* Read the status byte - only reset bit and line should be set */
+	temp1 = i2c_smbus_read_byte(client);
+	if (temp1 != (DS2482_REG_STS_LL | DS2482_REG_STS_RST)) {
+		dev_warn(&client->dev, "DS2482 reset status "
+			 "0x%02X - not a DS2482\n", temp1);
+		return err;
+	}
+
+	/* Detect the 8-port version */
+	data->w1_count = 1;
+	if (ds2482_set_channel(data, 7) == 0)
+		data->w1_count = 8;
+
+	/* Set all config items to 0 (off) */
+	ds2482_send_cmd_data(data, DS2482_CMD_WRITE_CONFIG,
+		ds2482_calculate_config(0x00));
+
+	mutex_init(&data->access_lock);
+
+	/* Register 1-wire interface(s) */
+	for (idx = 0; idx < data->w1_count; idx++) {
+		data->w1_ch[idx].pdev = data;
+		data->w1_ch[idx].channel = idx;
+
+		/* Populate all the w1 bus master stuff */
+		data->w1_ch[idx].w1_bm.data       = &data->w1_ch[idx];
+		data->w1_ch[idx].w1_bm.read_byte  = ds2482_w1_read_byte;
+		data->w1_ch[idx].w1_bm.write_byte = ds2482_w1_write_byte;
+		data->w1_ch[idx].w1_bm.touch_bit  = ds2482_w1_touch_bit;
+		data->w1_ch[idx].w1_bm.triplet    = ds2482_w1_triplet;
+		data->w1_ch[idx].w1_bm.reset_bus  = ds2482_w1_reset_bus;
+		data->w1_ch[idx].w1_bm.set_pullup = ds2482_w1_set_pullup;
+
+		err = w1_add_master_device(&data->w1_ch[idx].w1_bm);
+		if (err) {
+			data->w1_ch[idx].pdev = NULL;
+			goto exit_w1_remove;
+		}
+	}
+
+	return 0;
+
+exit_w1_remove:
+	for (idx = 0; idx < data->w1_count; idx++) {
+		if (data->w1_ch[idx].pdev != NULL)
+			w1_remove_master_device(&data->w1_ch[idx].w1_bm);
+	}
+	return err;
+}
+
+static void ds2482_remove(struct i2c_client *client)
+{
+	struct ds2482_data   *data = i2c_get_clientdata(client);
+	int idx;
+
+	/* Unregister the 1-wire bridge(s) */
+	for (idx = 0; idx < data->w1_count; idx++) {
+		if (data->w1_ch[idx].pdev != NULL)
+			w1_remove_master_device(&data->w1_ch[idx].w1_bm);
+	}
+}
+
+/*
+ * Driver data (common to all clients)
+ */
+static const struct i2c_device_id ds2482_id[] = {
+	{ .name = "ds2482" },
+	{ .name = "ds2484" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ds2482_id);
+
+static struct i2c_driver ds2482_driver = {
+	.driver = {
+		.name	= "ds2482",
+	},
+	.probe		= ds2482_probe,
+	.remove		= ds2482_remove,
+	.id_table	= ds2482_id,
+};
+module_i2c_driver(ds2482_driver);
+
+MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
+MODULE_DESCRIPTION("DS2482 driver");
+
+MODULE_LICENSE("GPL");

linux-7.2.3/drivers/w1/masters/matrox_w1.c

@@ -0,0 +1,198 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	matrox_w1.c
+ *
+ * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
+ */
+
+#include <asm/types.h>
+#include <linux/atomic.h>
+#include <linux/io.h>
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/pci_ids.h>
+#include <linux/pci.h>
+
+#include <linux/w1.h>
+
+/*
+ * Matrox G400 DDC registers.
+ */
+
+#define MATROX_G400_DDC_CLK		(1<<4)
+#define MATROX_G400_DDC_DATA		(1<<1)
+
+#define MATROX_BASE			0x3C00
+#define MATROX_STATUS			0x1e14
+
+#define MATROX_PORT_INDEX_OFFSET	0x00
+#define MATROX_PORT_DATA_OFFSET		0x0A
+
+#define MATROX_GET_CONTROL		0x2A
+#define MATROX_GET_DATA			0x2B
+#define MATROX_CURSOR_CTL		0x06
+
+struct matrox_device {
+	void __iomem *base_addr;
+	void __iomem *port_index;
+	void __iomem *port_data;
+	u8 data_mask;
+
+	unsigned long phys_addr;
+	void __iomem *virt_addr;
+
+	struct w1_bus_master *bus_master;
+};
+
+/*
+ * These functions read and write DDC Data bit.
+ *
+ * Using tristate pins, since i can't find any open-drain pin in whole motherboard.
+ * Unfortunately we can't connect to Intel's 82801xx IO controller
+ * since we don't know motherboard schema, which has pretty unused(may be not) GPIO.
+ *
+ * I've heard that PIIX also has open drain pin.
+ *
+ * Port mapping.
+ */
+static inline u8 matrox_w1_read_reg(struct matrox_device *dev, u8 reg)
+{
+	u8 ret;
+
+	writeb(reg, dev->port_index);
+	ret = readb(dev->port_data);
+	barrier();
+
+	return ret;
+}
+
+static inline void matrox_w1_write_reg(struct matrox_device *dev, u8 reg, u8 val)
+{
+	writeb(reg, dev->port_index);
+	writeb(val, dev->port_data);
+	wmb();
+}
+
+static void matrox_w1_write_ddc_bit(void *data, u8 bit)
+{
+	u8 ret;
+	struct matrox_device *dev = data;
+
+	if (bit)
+		bit = 0;
+	else
+		bit = dev->data_mask;
+
+	ret = matrox_w1_read_reg(dev, MATROX_GET_CONTROL);
+	matrox_w1_write_reg(dev, MATROX_GET_CONTROL, ((ret & ~dev->data_mask) | bit));
+	matrox_w1_write_reg(dev, MATROX_GET_DATA, 0x00);
+}
+
+static u8 matrox_w1_read_ddc_bit(void *data)
+{
+	u8 ret;
+	struct matrox_device *dev = data;
+
+	ret = matrox_w1_read_reg(dev, MATROX_GET_DATA);
+
+	return ret;
+}
+
+static void matrox_w1_hw_init(struct matrox_device *dev)
+{
+	matrox_w1_write_reg(dev, MATROX_GET_DATA, 0xFF);
+	matrox_w1_write_reg(dev, MATROX_GET_CONTROL, 0x00);
+}
+
+static int matrox_w1_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
+{
+	struct matrox_device *dev;
+	int err;
+
+	if (pdev->vendor != PCI_VENDOR_ID_MATROX || pdev->device != PCI_DEVICE_ID_MATROX_G400)
+		return -ENODEV;
+
+	dev = kzalloc(sizeof(struct matrox_device) +
+		       sizeof(struct w1_bus_master), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->bus_master = (struct w1_bus_master *)(dev + 1);
+
+	/*
+	 * True for G400, for some other we need resource 0, see drivers/video/matrox/matroxfb_base.c
+	 */
+
+	dev->phys_addr = pci_resource_start(pdev, 1);
+
+	dev->virt_addr = ioremap(dev->phys_addr, 16384);
+	if (!dev->virt_addr) {
+		dev_err(&pdev->dev, "%s: failed to ioremap(0x%lx, %d).\n",
+			__func__, dev->phys_addr, 16384);
+		err = -EIO;
+		goto err_out_free_device;
+	}
+
+	dev->base_addr = dev->virt_addr + MATROX_BASE;
+	dev->port_index = dev->base_addr + MATROX_PORT_INDEX_OFFSET;
+	dev->port_data = dev->base_addr + MATROX_PORT_DATA_OFFSET;
+	dev->data_mask = (MATROX_G400_DDC_DATA);
+
+	matrox_w1_hw_init(dev);
+
+	dev->bus_master->data = dev;
+	dev->bus_master->read_bit = &matrox_w1_read_ddc_bit;
+	dev->bus_master->write_bit = &matrox_w1_write_ddc_bit;
+
+	err = w1_add_master_device(dev->bus_master);
+	if (err)
+		goto err_out_free_device;
+
+	pci_set_drvdata(pdev, dev);
+
+	dev_info(&pdev->dev, "Matrox G400 GPIO transport layer for 1-wire.\n");
+
+	return 0;
+
+err_out_free_device:
+	if (dev->virt_addr)
+		iounmap(dev->virt_addr);
+	kfree(dev);
+
+	return err;
+}
+
+static void matrox_w1_remove(struct pci_dev *pdev)
+{
+	struct matrox_device *dev = pci_get_drvdata(pdev);
+
+	w1_remove_master_device(dev->bus_master);
+	iounmap(dev->virt_addr);
+
+	kfree(dev);
+}
+
+static struct pci_device_id matrox_w1_tbl[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_MATROX, PCI_DEVICE_ID_MATROX_G400) },
+	{ },
+};
+MODULE_DEVICE_TABLE(pci, matrox_w1_tbl);
+
+static struct pci_driver matrox_w1_pci_driver = {
+	.name = "matrox_w1",
+	.id_table = matrox_w1_tbl,
+	.probe = matrox_w1_probe,
+	.remove = matrox_w1_remove,
+};
+module_pci_driver(matrox_w1_pci_driver);
+
+MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
+MODULE_DESCRIPTION("Driver for transport(Dallas 1-wire protocol) over VGA DDC(matrox gpio).");
+MODULE_LICENSE("GPL");

linux-7.2.3/drivers/w1/masters/mxc_w1.c

@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2005-2008 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2008 Luotao Fu, kernel@pengutronix.de
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/ktime.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <linux/w1.h>
+
+/*
+ * MXC W1 Register offsets
+ */
+#define MXC_W1_CONTROL		0x00
+# define MXC_W1_CONTROL_RDST	BIT(3)
+# define MXC_W1_CONTROL_WR(x)	BIT(5 - (x))
+# define MXC_W1_CONTROL_PST	BIT(6)
+# define MXC_W1_CONTROL_RPP	BIT(7)
+#define MXC_W1_TIME_DIVIDER	0x02
+#define MXC_W1_RESET		0x04
+# define MXC_W1_RESET_RST	BIT(0)
+
+struct mxc_w1_device {
+	void __iomem *regs;
+	struct clk *clk;
+	struct w1_bus_master bus_master;
+};
+
+/*
+ * this is the low level routine to
+ * reset the device on the One Wire interface
+ * on the hardware
+ */
+static u8 mxc_w1_ds2_reset_bus(void *data)
+{
+	struct mxc_w1_device *dev = data;
+	ktime_t timeout;
+
+	writeb(MXC_W1_CONTROL_RPP, dev->regs + MXC_W1_CONTROL);
+
+	/* Wait for reset sequence 511+512us, use 1500us for sure */
+	timeout = ktime_add_us(ktime_get(), 1500);
+
+	udelay(511 + 512);
+
+	do {
+		u8 ctrl = readb(dev->regs + MXC_W1_CONTROL);
+
+		/* PST bit is valid after the RPP bit is self-cleared */
+		if (!(ctrl & MXC_W1_CONTROL_RPP))
+			return !(ctrl & MXC_W1_CONTROL_PST);
+	} while (ktime_before(ktime_get(), timeout));
+
+	return 1;
+}
+
+/*
+ * this is the low level routine to read/write a bit on the One Wire
+ * interface on the hardware. It does write 0 if parameter bit is set
+ * to 0, otherwise a write 1/read.
+ */
+static u8 mxc_w1_ds2_touch_bit(void *data, u8 bit)
+{
+	struct mxc_w1_device *dev = data;
+	ktime_t timeout;
+
+	writeb(MXC_W1_CONTROL_WR(bit), dev->regs + MXC_W1_CONTROL);
+
+	/* Wait for read/write bit (60us, Max 120us), use 200us for sure */
+	timeout = ktime_add_us(ktime_get(), 200);
+
+	udelay(60);
+
+	do {
+		u8 ctrl = readb(dev->regs + MXC_W1_CONTROL);
+
+		/* RDST bit is valid after the WR1/RD bit is self-cleared */
+		if (!(ctrl & MXC_W1_CONTROL_WR(bit)))
+			return !!(ctrl & MXC_W1_CONTROL_RDST);
+	} while (ktime_before(ktime_get(), timeout));
+
+	return 0;
+}
+
+static int mxc_w1_probe(struct platform_device *pdev)
+{
+	struct mxc_w1_device *mdev;
+	unsigned long clkrate;
+	unsigned int clkdiv;
+	int err;
+
+	mdev = devm_kzalloc(&pdev->dev, sizeof(struct mxc_w1_device),
+			    GFP_KERNEL);
+	if (!mdev)
+		return -ENOMEM;
+
+	mdev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(mdev->clk))
+		return PTR_ERR(mdev->clk);
+
+	err = clk_prepare_enable(mdev->clk);
+	if (err)
+		return err;
+
+	clkrate = clk_get_rate(mdev->clk);
+	if (clkrate < 10000000)
+		dev_warn(&pdev->dev,
+			 "Low clock frequency causes improper function\n");
+
+	clkdiv = DIV_ROUND_CLOSEST(clkrate, 1000000);
+	clkrate /= clkdiv;
+	if ((clkrate < 980000) || (clkrate > 1020000))
+		dev_warn(&pdev->dev,
+			 "Incorrect time base frequency %lu Hz\n", clkrate);
+
+	mdev->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(mdev->regs)) {
+		err = PTR_ERR(mdev->regs);
+		goto out_disable_clk;
+	}
+
+	/* Software reset 1-Wire module */
+	writeb(MXC_W1_RESET_RST, mdev->regs + MXC_W1_RESET);
+	writeb(0, mdev->regs + MXC_W1_RESET);
+
+	writeb(clkdiv - 1, mdev->regs + MXC_W1_TIME_DIVIDER);
+
+	mdev->bus_master.data = mdev;
+	mdev->bus_master.reset_bus = mxc_w1_ds2_reset_bus;
+	mdev->bus_master.touch_bit = mxc_w1_ds2_touch_bit;
+
+	platform_set_drvdata(pdev, mdev);
+
+	err = w1_add_master_device(&mdev->bus_master);
+	if (err)
+		goto out_disable_clk;
+
+	return 0;
+
+out_disable_clk:
+	clk_disable_unprepare(mdev->clk);
+	return err;
+}
+
+/*
+ * disassociate the w1 device from the driver
+ */
+static void mxc_w1_remove(struct platform_device *pdev)
+{
+	struct mxc_w1_device *mdev = platform_get_drvdata(pdev);
+
+	w1_remove_master_device(&mdev->bus_master);
+
+	clk_disable_unprepare(mdev->clk);
+}
+
+static const struct of_device_id mxc_w1_dt_ids[] = {
+	{ .compatible = "fsl,imx21-owire" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mxc_w1_dt_ids);
+
+static struct platform_driver mxc_w1_driver = {
+	.driver = {
+		.name = "mxc_w1",
+		.of_match_table = mxc_w1_dt_ids,
+	},
+	.probe = mxc_w1_probe,
+	.remove = mxc_w1_remove,
+};
+module_platform_driver(mxc_w1_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Freescale Semiconductors Inc");
+MODULE_DESCRIPTION("Driver for One-Wire on MXC");

linux-7.2.3/drivers/w1/masters/omap_hdq.c

@@ -0,0 +1,681 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2007,2012 Texas Instruments, Inc.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/sched.h>
+#include <linux/pm_runtime.h>
+#include <linux/of.h>
+
+#include <linux/w1.h>
+
+#define	MOD_NAME	"OMAP_HDQ:"
+
+#define OMAP_HDQ_REVISION			0x00
+#define OMAP_HDQ_TX_DATA			0x04
+#define OMAP_HDQ_RX_DATA			0x08
+#define OMAP_HDQ_CTRL_STATUS			0x0c
+#define OMAP_HDQ_CTRL_STATUS_SINGLE		BIT(7)
+#define OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK	BIT(6)
+#define OMAP_HDQ_CTRL_STATUS_CLOCKENABLE	BIT(5)
+#define OMAP_HDQ_CTRL_STATUS_GO                 BIT(4)
+#define OMAP_HDQ_CTRL_STATUS_PRESENCE		BIT(3)
+#define OMAP_HDQ_CTRL_STATUS_INITIALIZATION	BIT(2)
+#define OMAP_HDQ_CTRL_STATUS_DIR		BIT(1)
+#define OMAP_HDQ_INT_STATUS			0x10
+#define OMAP_HDQ_INT_STATUS_TXCOMPLETE		BIT(2)
+#define OMAP_HDQ_INT_STATUS_RXCOMPLETE		BIT(1)
+#define OMAP_HDQ_INT_STATUS_TIMEOUT		BIT(0)
+
+#define OMAP_HDQ_FLAG_CLEAR			0
+#define OMAP_HDQ_FLAG_SET			1
+#define OMAP_HDQ_TIMEOUT			(HZ/5)
+
+#define OMAP_HDQ_MAX_USER			4
+
+static DECLARE_WAIT_QUEUE_HEAD(hdq_wait_queue);
+
+static int w1_id;
+module_param(w1_id, int, 0400);
+MODULE_PARM_DESC(w1_id, "1-wire id for the slave detection in HDQ mode");
+
+struct hdq_data {
+	struct device		*dev;
+	void __iomem		*hdq_base;
+	/* lock read/write/break operations */
+	struct  mutex		hdq_mutex;
+	/* interrupt status and a lock for it */
+	u8			hdq_irqstatus;
+	spinlock_t		hdq_spinlock;
+	/* mode: 0-HDQ 1-W1 */
+	int                     mode;
+
+};
+
+/* HDQ register I/O routines */
+static inline u8 hdq_reg_in(struct hdq_data *hdq_data, u32 offset)
+{
+	return __raw_readl(hdq_data->hdq_base + offset);
+}
+
+static inline void hdq_reg_out(struct hdq_data *hdq_data, u32 offset, u8 val)
+{
+	__raw_writel(val, hdq_data->hdq_base + offset);
+}
+
+static inline u8 hdq_reg_merge(struct hdq_data *hdq_data, u32 offset,
+			u8 val, u8 mask)
+{
+	u8 new_val = (__raw_readl(hdq_data->hdq_base + offset) & ~mask)
+			| (val & mask);
+	__raw_writel(new_val, hdq_data->hdq_base + offset);
+
+	return new_val;
+}
+
+/*
+ * Wait for one or more bits in flag change.
+ * HDQ_FLAG_SET: wait until any bit in the flag is set.
+ * HDQ_FLAG_CLEAR: wait until all bits in the flag are cleared.
+ * return 0 on success and -ETIMEDOUT in the case of timeout.
+ */
+static int hdq_wait_for_flag(struct hdq_data *hdq_data, u32 offset,
+		u8 flag, u8 flag_set, u8 *status)
+{
+	int ret = 0;
+	unsigned long timeout = jiffies + OMAP_HDQ_TIMEOUT;
+
+	if (flag_set == OMAP_HDQ_FLAG_CLEAR) {
+		/* wait for the flag clear */
+		while (((*status = hdq_reg_in(hdq_data, offset)) & flag)
+			&& time_before(jiffies, timeout)) {
+			schedule_timeout_uninterruptible(1);
+		}
+		if (*status & flag)
+			ret = -ETIMEDOUT;
+	} else if (flag_set == OMAP_HDQ_FLAG_SET) {
+		/* wait for the flag set */
+		while (!((*status = hdq_reg_in(hdq_data, offset)) & flag)
+			&& time_before(jiffies, timeout)) {
+			schedule_timeout_uninterruptible(1);
+		}
+		if (!(*status & flag))
+			ret = -ETIMEDOUT;
+	} else
+		return -EINVAL;
+
+	return ret;
+}
+
+/* Clear saved irqstatus after using an interrupt */
+static u8 hdq_reset_irqstatus(struct hdq_data *hdq_data, u8 bits)
+{
+	unsigned long irqflags;
+	u8 status;
+
+	spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
+	status = hdq_data->hdq_irqstatus;
+	/* this is a read-modify-write */
+	hdq_data->hdq_irqstatus &= ~bits;
+	spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
+
+	return status;
+}
+
+/* write out a byte and fill *status with HDQ_INT_STATUS */
+static int hdq_write_byte(struct hdq_data *hdq_data, u8 val, u8 *status)
+{
+	int ret;
+	u8 tmp_status;
+
+	ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
+	if (ret < 0) {
+		ret = -EINTR;
+		goto rtn;
+	}
+
+	if (hdq_data->hdq_irqstatus)
+		dev_err(hdq_data->dev, "TX irqstatus not cleared (%02x)\n",
+			hdq_data->hdq_irqstatus);
+
+	*status = 0;
+
+	hdq_reg_out(hdq_data, OMAP_HDQ_TX_DATA, val);
+
+	/* set the GO bit */
+	hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS, OMAP_HDQ_CTRL_STATUS_GO,
+		OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO);
+	/* wait for the TXCOMPLETE bit */
+	ret = wait_event_timeout(hdq_wait_queue,
+		(hdq_data->hdq_irqstatus & OMAP_HDQ_INT_STATUS_TXCOMPLETE),
+		OMAP_HDQ_TIMEOUT);
+	*status = hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_TXCOMPLETE);
+	if (ret == 0) {
+		dev_dbg(hdq_data->dev, "TX wait elapsed\n");
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	/* check irqstatus */
+	if (!(*status & OMAP_HDQ_INT_STATUS_TXCOMPLETE)) {
+		dev_dbg(hdq_data->dev, "timeout waiting for"
+			" TXCOMPLETE/RXCOMPLETE, %x\n", *status);
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	/* wait for the GO bit return to zero */
+	ret = hdq_wait_for_flag(hdq_data, OMAP_HDQ_CTRL_STATUS,
+			OMAP_HDQ_CTRL_STATUS_GO,
+			OMAP_HDQ_FLAG_CLEAR, &tmp_status);
+	if (ret) {
+		dev_dbg(hdq_data->dev, "timeout waiting GO bit"
+			" return to zero, %x\n", tmp_status);
+	}
+
+out:
+	mutex_unlock(&hdq_data->hdq_mutex);
+rtn:
+	return ret;
+}
+
+/* HDQ Interrupt service routine */
+static irqreturn_t hdq_isr(int irq, void *_hdq)
+{
+	struct hdq_data *hdq_data = _hdq;
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&hdq_data->hdq_spinlock, irqflags);
+	hdq_data->hdq_irqstatus |= hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
+	spin_unlock_irqrestore(&hdq_data->hdq_spinlock, irqflags);
+	dev_dbg(hdq_data->dev, "hdq_isr: %x\n", hdq_data->hdq_irqstatus);
+
+	if (hdq_data->hdq_irqstatus &
+		(OMAP_HDQ_INT_STATUS_TXCOMPLETE | OMAP_HDQ_INT_STATUS_RXCOMPLETE
+		| OMAP_HDQ_INT_STATUS_TIMEOUT)) {
+		/* wake up sleeping process */
+		wake_up(&hdq_wait_queue);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/* W1 search callback function  in HDQ mode */
+static void omap_w1_search_bus(void *_hdq, struct w1_master *master_dev,
+		u8 search_type, w1_slave_found_callback slave_found)
+{
+	u64 module_id, rn_le, cs, id;
+
+	if (w1_id)
+		module_id = w1_id;
+	else
+		module_id = 0x1;
+
+	rn_le = cpu_to_le64(module_id);
+	/*
+	 * HDQ might not obey truly the 1-wire spec.
+	 * So calculate CRC based on module parameter.
+	 */
+	cs = w1_calc_crc8((u8 *)&rn_le, 7);
+	id = (cs << 56) | module_id;
+
+	slave_found(master_dev, id);
+}
+
+/* Issue break pulse to the device */
+static int omap_hdq_break(struct hdq_data *hdq_data)
+{
+	int ret = 0;
+	u8 tmp_status;
+
+	ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
+	if (ret < 0) {
+		dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
+		ret = -EINTR;
+		goto rtn;
+	}
+
+	if (hdq_data->hdq_irqstatus)
+		dev_err(hdq_data->dev, "break irqstatus not cleared (%02x)\n",
+			hdq_data->hdq_irqstatus);
+
+	/* set the INIT and GO bit */
+	hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS,
+		OMAP_HDQ_CTRL_STATUS_INITIALIZATION | OMAP_HDQ_CTRL_STATUS_GO,
+		OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_INITIALIZATION |
+		OMAP_HDQ_CTRL_STATUS_GO);
+
+	/* wait for the TIMEOUT bit */
+	ret = wait_event_timeout(hdq_wait_queue,
+		(hdq_data->hdq_irqstatus & OMAP_HDQ_INT_STATUS_TIMEOUT),
+		OMAP_HDQ_TIMEOUT);
+	tmp_status = hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_TIMEOUT);
+	if (ret == 0) {
+		dev_dbg(hdq_data->dev, "break wait elapsed\n");
+		ret = -EINTR;
+		goto out;
+	}
+
+	/* check irqstatus */
+	if (!(tmp_status & OMAP_HDQ_INT_STATUS_TIMEOUT)) {
+		dev_dbg(hdq_data->dev, "timeout waiting for TIMEOUT, %x\n",
+			tmp_status);
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	/*
+	 * check for the presence detect bit to get
+	 * set to show that the slave is responding
+	 */
+	if (!(hdq_reg_in(hdq_data, OMAP_HDQ_CTRL_STATUS) &
+			OMAP_HDQ_CTRL_STATUS_PRESENCE)) {
+		dev_dbg(hdq_data->dev, "Presence bit not set\n");
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	/*
+	 * wait for both INIT and GO bits rerurn to zero.
+	 * zero wait time expected for interrupt mode.
+	 */
+	ret = hdq_wait_for_flag(hdq_data, OMAP_HDQ_CTRL_STATUS,
+			OMAP_HDQ_CTRL_STATUS_INITIALIZATION |
+			OMAP_HDQ_CTRL_STATUS_GO, OMAP_HDQ_FLAG_CLEAR,
+			&tmp_status);
+	if (ret)
+		dev_dbg(hdq_data->dev, "timeout waiting INIT&GO bits"
+			" return to zero, %x\n", tmp_status);
+
+out:
+	mutex_unlock(&hdq_data->hdq_mutex);
+rtn:
+	return ret;
+}
+
+static int hdq_read_byte(struct hdq_data *hdq_data, u8 *val)
+{
+	int ret = 0;
+	u8 status;
+
+	ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
+	if (ret < 0) {
+		ret = -EINTR;
+		goto rtn;
+	}
+
+	if (pm_runtime_suspended(hdq_data->dev)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (!(hdq_data->hdq_irqstatus & OMAP_HDQ_INT_STATUS_RXCOMPLETE)) {
+		hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS,
+			OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO,
+			OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO);
+		/*
+		 * The RX comes immediately after TX.
+		 */
+		wait_event_timeout(hdq_wait_queue,
+				   (hdq_data->hdq_irqstatus
+				    & (OMAP_HDQ_INT_STATUS_RXCOMPLETE |
+				       OMAP_HDQ_INT_STATUS_TIMEOUT)),
+				   OMAP_HDQ_TIMEOUT);
+		status = hdq_reset_irqstatus(hdq_data,
+					     OMAP_HDQ_INT_STATUS_RXCOMPLETE |
+					     OMAP_HDQ_INT_STATUS_TIMEOUT);
+		hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS, 0,
+			OMAP_HDQ_CTRL_STATUS_DIR);
+
+		/* check irqstatus */
+		if (!(status & OMAP_HDQ_INT_STATUS_RXCOMPLETE)) {
+			dev_dbg(hdq_data->dev, "timeout waiting for"
+				" RXCOMPLETE, %x", status);
+			ret = -ETIMEDOUT;
+			goto out;
+		}
+	} else { /* interrupt had occurred before hdq_read_byte was called */
+		hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_RXCOMPLETE);
+	}
+	/* the data is ready. Read it in! */
+	*val = hdq_reg_in(hdq_data, OMAP_HDQ_RX_DATA);
+out:
+	mutex_unlock(&hdq_data->hdq_mutex);
+rtn:
+	return ret;
+
+}
+
+/*
+ * W1 triplet callback function - used for searching ROM addresses.
+ * Registered only when controller is in 1-wire mode.
+ */
+static u8 omap_w1_triplet(void *_hdq, u8 bdir)
+{
+	u8 id_bit, comp_bit;
+	int err;
+	u8 ret = 0x3; /* no slaves responded */
+	struct hdq_data *hdq_data = _hdq;
+	u8 ctrl = OMAP_HDQ_CTRL_STATUS_SINGLE | OMAP_HDQ_CTRL_STATUS_GO |
+		  OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK;
+	u8 mask = ctrl | OMAP_HDQ_CTRL_STATUS_DIR;
+
+	err = pm_runtime_get_sync(hdq_data->dev);
+	if (err < 0) {
+		pm_runtime_put_noidle(hdq_data->dev);
+
+		return err;
+	}
+
+	err = mutex_lock_interruptible(&hdq_data->hdq_mutex);
+	if (err < 0) {
+		dev_dbg(hdq_data->dev, "Could not acquire mutex\n");
+		goto rtn;
+	}
+
+	/* read id_bit */
+	hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS,
+		      ctrl | OMAP_HDQ_CTRL_STATUS_DIR, mask);
+	err = wait_event_timeout(hdq_wait_queue,
+				 (hdq_data->hdq_irqstatus
+				  & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
+				 OMAP_HDQ_TIMEOUT);
+	/* Must clear irqstatus for another RXCOMPLETE interrupt */
+	hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_RXCOMPLETE);
+
+	if (err == 0) {
+		dev_dbg(hdq_data->dev, "RX wait elapsed\n");
+		goto out;
+	}
+	id_bit = (hdq_reg_in(_hdq, OMAP_HDQ_RX_DATA) & 0x01);
+
+	/* read comp_bit */
+	hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS,
+		      ctrl | OMAP_HDQ_CTRL_STATUS_DIR, mask);
+	err = wait_event_timeout(hdq_wait_queue,
+				 (hdq_data->hdq_irqstatus
+				  & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
+				 OMAP_HDQ_TIMEOUT);
+	/* Must clear irqstatus for another RXCOMPLETE interrupt */
+	hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_RXCOMPLETE);
+
+	if (err == 0) {
+		dev_dbg(hdq_data->dev, "RX wait elapsed\n");
+		goto out;
+	}
+	comp_bit = (hdq_reg_in(_hdq, OMAP_HDQ_RX_DATA) & 0x01);
+
+	if (id_bit && comp_bit) {
+		ret = 0x03;  /* no slaves responded */
+		goto out;
+	}
+	if (!id_bit && !comp_bit) {
+		/* Both bits are valid, take the direction given */
+		ret = bdir ? 0x04 : 0;
+	} else {
+		/* Only one bit is valid, take that direction */
+		bdir = id_bit;
+		ret = id_bit ? 0x05 : 0x02;
+	}
+
+	/* write bdir bit */
+	hdq_reg_out(_hdq, OMAP_HDQ_TX_DATA, bdir);
+	hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS, ctrl, mask);
+	err = wait_event_timeout(hdq_wait_queue,
+				 (hdq_data->hdq_irqstatus
+				  & OMAP_HDQ_INT_STATUS_TXCOMPLETE),
+				 OMAP_HDQ_TIMEOUT);
+	/* Must clear irqstatus for another TXCOMPLETE interrupt */
+	hdq_reset_irqstatus(hdq_data, OMAP_HDQ_INT_STATUS_TXCOMPLETE);
+
+	if (err == 0) {
+		dev_dbg(hdq_data->dev, "TX wait elapsed\n");
+		goto out;
+	}
+
+	hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS, 0,
+		      OMAP_HDQ_CTRL_STATUS_SINGLE);
+
+out:
+	mutex_unlock(&hdq_data->hdq_mutex);
+rtn:
+	pm_runtime_put_autosuspend(hdq_data->dev);
+
+	return ret;
+}
+
+/* reset callback */
+static u8 omap_w1_reset_bus(void *_hdq)
+{
+	struct hdq_data *hdq_data = _hdq;
+	int err;
+
+	err = pm_runtime_get_sync(hdq_data->dev);
+	if (err < 0) {
+		pm_runtime_put_noidle(hdq_data->dev);
+
+		return err;
+	}
+
+	omap_hdq_break(hdq_data);
+
+	pm_runtime_put_autosuspend(hdq_data->dev);
+
+	return 0;
+}
+
+/* Read a byte of data from the device */
+static u8 omap_w1_read_byte(void *_hdq)
+{
+	struct hdq_data *hdq_data = _hdq;
+	u8 val = 0;
+	int ret;
+
+	ret = pm_runtime_get_sync(hdq_data->dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(hdq_data->dev);
+
+		return -1;
+	}
+
+	ret = hdq_read_byte(hdq_data, &val);
+	if (ret)
+		val = -1;
+
+	pm_runtime_put_autosuspend(hdq_data->dev);
+
+	return val;
+}
+
+/* Write a byte of data to the device */
+static void omap_w1_write_byte(void *_hdq, u8 byte)
+{
+	struct hdq_data *hdq_data = _hdq;
+	int ret;
+	u8 status;
+
+	ret = pm_runtime_get_sync(hdq_data->dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(hdq_data->dev);
+
+		return;
+	}
+
+	/*
+	 * We need to reset the slave before
+	 * issuing the SKIP ROM command, else
+	 * the slave will not work.
+	 */
+	if (byte == W1_SKIP_ROM)
+		omap_hdq_break(hdq_data);
+
+	ret = hdq_write_byte(hdq_data, byte, &status);
+	if (ret < 0) {
+		dev_dbg(hdq_data->dev, "TX failure:Ctrl status %x\n", status);
+		goto out_err;
+	}
+
+out_err:
+	pm_runtime_put_autosuspend(hdq_data->dev);
+}
+
+static struct w1_bus_master omap_w1_master = {
+	.read_byte	= omap_w1_read_byte,
+	.write_byte	= omap_w1_write_byte,
+	.reset_bus	= omap_w1_reset_bus,
+};
+
+static int __maybe_unused omap_hdq_runtime_suspend(struct device *dev)
+{
+	struct hdq_data *hdq_data = dev_get_drvdata(dev);
+
+	hdq_reg_out(hdq_data, 0, hdq_data->mode);
+	hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
+
+	return 0;
+}
+
+static int __maybe_unused omap_hdq_runtime_resume(struct device *dev)
+{
+	struct hdq_data *hdq_data = dev_get_drvdata(dev);
+
+	/* select HDQ/1W mode & enable clocks */
+	hdq_reg_out(hdq_data, OMAP_HDQ_CTRL_STATUS,
+		    OMAP_HDQ_CTRL_STATUS_CLOCKENABLE |
+		    OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK |
+		    hdq_data->mode);
+	hdq_reg_in(hdq_data, OMAP_HDQ_INT_STATUS);
+
+	return 0;
+}
+
+static const struct dev_pm_ops omap_hdq_pm_ops = {
+	SET_RUNTIME_PM_OPS(omap_hdq_runtime_suspend,
+			   omap_hdq_runtime_resume, NULL)
+};
+
+static int omap_hdq_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct hdq_data *hdq_data;
+	int ret, irq;
+	u8 rev;
+	const char *mode;
+
+	hdq_data = devm_kzalloc(dev, sizeof(*hdq_data), GFP_KERNEL);
+	if (!hdq_data)
+		return -ENOMEM;
+
+	hdq_data->dev = dev;
+	platform_set_drvdata(pdev, hdq_data);
+
+	hdq_data->hdq_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(hdq_data->hdq_base))
+		return PTR_ERR(hdq_data->hdq_base);
+
+	mutex_init(&hdq_data->hdq_mutex);
+
+	ret = of_property_read_string(pdev->dev.of_node, "ti,mode", &mode);
+	if (ret < 0 || !strcmp(mode, "hdq")) {
+		hdq_data->mode = 0;
+		omap_w1_master.search = omap_w1_search_bus;
+	} else {
+		hdq_data->mode = 1;
+		omap_w1_master.triplet = omap_w1_triplet;
+	}
+
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 300);
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(&pdev->dev);
+		dev_dbg(&pdev->dev, "pm_runtime_get_sync failed\n");
+		goto err_w1;
+	}
+
+	rev = hdq_reg_in(hdq_data, OMAP_HDQ_REVISION);
+	dev_info(&pdev->dev, "OMAP HDQ Hardware Rev %c.%c. Driver in %s mode\n",
+		(rev >> 4) + '0', (rev & 0x0f) + '0', "Interrupt");
+
+	spin_lock_init(&hdq_data->hdq_spinlock);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq	< 0) {
+		dev_dbg(&pdev->dev, "Failed to get IRQ: %d\n", irq);
+		ret = irq;
+		goto err_irq;
+	}
+
+	ret = devm_request_irq(dev, irq, hdq_isr, 0, "omap_hdq", hdq_data);
+	if (ret < 0) {
+		dev_dbg(&pdev->dev, "could not request irq\n");
+		goto err_irq;
+	}
+
+	omap_hdq_break(hdq_data);
+
+	pm_runtime_put_autosuspend(&pdev->dev);
+
+	omap_w1_master.data = hdq_data;
+
+	ret = w1_add_master_device(&omap_w1_master);
+	if (ret) {
+		dev_dbg(&pdev->dev, "Failure in registering w1 master\n");
+		goto err_w1;
+	}
+
+	return 0;
+
+err_irq:
+	pm_runtime_put_sync(&pdev->dev);
+err_w1:
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return ret;
+}
+
+static void omap_hdq_remove(struct platform_device *pdev)
+{
+	int active;
+
+	active = pm_runtime_get_sync(&pdev->dev);
+	if (active < 0)
+		pm_runtime_put_noidle(&pdev->dev);
+
+	w1_remove_master_device(&omap_w1_master);
+
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+	if (active >= 0)
+		pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+}
+
+static const struct of_device_id omap_hdq_dt_ids[] = {
+	{ .compatible = "ti,omap3-1w" },
+	{ .compatible = "ti,am4372-hdq" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, omap_hdq_dt_ids);
+
+static struct platform_driver omap_hdq_driver = {
+	.probe = omap_hdq_probe,
+	.remove = omap_hdq_remove,
+	.driver = {
+		.name =	"omap_hdq",
+		.of_match_table = omap_hdq_dt_ids,
+		.pm = &omap_hdq_pm_ops,
+	},
+};
+module_platform_driver(omap_hdq_driver);
+
+MODULE_AUTHOR("Texas Instruments");
+MODULE_DESCRIPTION("HDQ-1W driver Library");
+MODULE_LICENSE("GPL");

linux-7.2.3/drivers/w1/masters/sgi_w1.c

@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * sgi_w1.c - w1 master driver for one wire support in SGI ASICs
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/sgi-w1.h>
+
+#include <linux/w1.h>
+
+#define MCR_RD_DATA	BIT(0)
+#define MCR_DONE	BIT(1)
+
+#define MCR_PACK(pulse, sample) (((pulse) << 10) | ((sample) << 2))
+
+struct sgi_w1_device {
+	u32 __iomem *mcr;
+	struct w1_bus_master bus_master;
+	char dev_id[64];
+};
+
+static u8 sgi_w1_wait(u32 __iomem *mcr)
+{
+	u32 mcr_val;
+
+	do {
+		mcr_val = readl(mcr);
+	} while (!(mcr_val & MCR_DONE));
+
+	return (mcr_val & MCR_RD_DATA) ? 1 : 0;
+}
+
+/*
+ * this is the low level routine to
+ * reset the device on the One Wire interface
+ * on the hardware
+ */
+static u8 sgi_w1_reset_bus(void *data)
+{
+	struct sgi_w1_device *dev = data;
+	u8 ret;
+
+	writel(MCR_PACK(520, 65), dev->mcr);
+	ret = sgi_w1_wait(dev->mcr);
+	udelay(500); /* recovery time */
+	return ret;
+}
+
+/*
+ * this is the low level routine to read/write a bit on the One Wire
+ * interface on the hardware. It does write 0 if parameter bit is set
+ * to 0, otherwise a write 1/read.
+ */
+static u8 sgi_w1_touch_bit(void *data, u8 bit)
+{
+	struct sgi_w1_device *dev = data;
+	u8 ret;
+
+	if (bit)
+		writel(MCR_PACK(6, 13), dev->mcr);
+	else
+		writel(MCR_PACK(80, 30), dev->mcr);
+
+	ret = sgi_w1_wait(dev->mcr);
+	if (bit)
+		udelay(100); /* recovery */
+	return ret;
+}
+
+static int sgi_w1_probe(struct platform_device *pdev)
+{
+	struct sgi_w1_device *sdev;
+	struct sgi_w1_platform_data *pdata;
+
+	sdev = devm_kzalloc(&pdev->dev, sizeof(struct sgi_w1_device),
+			    GFP_KERNEL);
+	if (!sdev)
+		return -ENOMEM;
+
+	sdev->mcr = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(sdev->mcr))
+		return PTR_ERR(sdev->mcr);
+
+	sdev->bus_master.data = sdev;
+	sdev->bus_master.reset_bus = sgi_w1_reset_bus;
+	sdev->bus_master.touch_bit = sgi_w1_touch_bit;
+
+	pdata = dev_get_platdata(&pdev->dev);
+	if (pdata) {
+		strscpy(sdev->dev_id, pdata->dev_id, sizeof(sdev->dev_id));
+		sdev->bus_master.dev_id = sdev->dev_id;
+	}
+
+	platform_set_drvdata(pdev, sdev);
+
+	return w1_add_master_device(&sdev->bus_master);
+}
+
+/*
+ * disassociate the w1 device from the driver
+ */
+static void sgi_w1_remove(struct platform_device *pdev)
+{
+	struct sgi_w1_device *sdev = platform_get_drvdata(pdev);
+
+	w1_remove_master_device(&sdev->bus_master);
+}
+
+static struct platform_driver sgi_w1_driver = {
+	.driver = {
+		.name = "sgi_w1",
+	},
+	.probe = sgi_w1_probe,
+	.remove = sgi_w1_remove,
+};
+module_platform_driver(sgi_w1_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Thomas Bogendoerfer");
+MODULE_DESCRIPTION("Driver for One-Wire IP in SGI ASICs");

linux-7.2.3/drivers/w1/masters/w1-gpio.c

@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * w1-gpio - GPIO w1 bus master driver
+ *
+ * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/types.h>
+
+#include <linux/w1.h>
+
+struct w1_gpio_ddata {
+	struct gpio_desc *gpiod;
+	struct gpio_desc *pullup_gpiod;
+	unsigned int pullup_duration;
+};
+
+static u8 w1_gpio_set_pullup(void *data, int delay)
+{
+	struct w1_gpio_ddata *ddata = data;
+
+	if (delay) {
+		ddata->pullup_duration = delay;
+	} else {
+		if (ddata->pullup_duration) {
+			/*
+			 * This will OVERRIDE open drain emulation and force-pull
+			 * the line high for some time.
+			 */
+			gpiod_set_raw_value(ddata->gpiod, 1);
+			msleep(ddata->pullup_duration);
+			/*
+			 * This will simply set the line as input since we are doing
+			 * open drain emulation in the GPIO library.
+			 */
+			gpiod_set_value(ddata->gpiod, 1);
+		}
+		ddata->pullup_duration = 0;
+	}
+
+	return 0;
+}
+
+static void w1_gpio_write_bit(void *data, u8 bit)
+{
+	struct w1_gpio_ddata *ddata = data;
+
+	gpiod_set_value(ddata->gpiod, bit);
+}
+
+static u8 w1_gpio_read_bit(void *data)
+{
+	struct w1_gpio_ddata *ddata = data;
+
+	return gpiod_get_value(ddata->gpiod) ? 1 : 0;
+}
+
+static int w1_gpio_probe(struct platform_device *pdev)
+{
+	struct w1_bus_master *master;
+	struct w1_gpio_ddata *ddata;
+	struct device *dev = &pdev->dev;
+	/* Enforce open drain mode by default */
+	enum gpiod_flags gflags = GPIOD_OUT_LOW_OPEN_DRAIN;
+	int err;
+
+	ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	/*
+	 * This parameter means that something else than the gpiolib has
+	 * already set the line into open drain mode, so we should just
+	 * driver it high/low like we are in full control of the line and
+	 * open drain will happen transparently.
+	 */
+	if (device_property_present(dev, "linux,open-drain"))
+		gflags = GPIOD_OUT_LOW;
+
+	master = devm_kzalloc(dev, sizeof(*master), GFP_KERNEL);
+	if (!master)
+		return -ENOMEM;
+
+	ddata->gpiod = devm_gpiod_get_index(dev, NULL, 0, gflags);
+	if (IS_ERR(ddata->gpiod))
+		return dev_err_probe(dev, PTR_ERR(ddata->gpiod), "gpio_request (pin) failed\n");
+
+	ddata->pullup_gpiod =
+		devm_gpiod_get_index_optional(dev, NULL, 1, GPIOD_OUT_LOW);
+	if (IS_ERR(ddata->pullup_gpiod))
+		return dev_err_probe(dev, PTR_ERR(ddata->pullup_gpiod),
+				     "gpio_request (ext_pullup_enable_pin) failed\n");
+
+	master->data = ddata;
+	master->read_bit = w1_gpio_read_bit;
+	gpiod_direction_output(ddata->gpiod, 1);
+	master->write_bit = w1_gpio_write_bit;
+
+	/*
+	 * If we are using open drain emulation from the GPIO library,
+	 * we need to use this pullup function that hammers the line
+	 * high using a raw accessor to provide pull-up for the w1
+	 * line.
+	 */
+	if (gflags == GPIOD_OUT_LOW_OPEN_DRAIN)
+		master->set_pullup = w1_gpio_set_pullup;
+
+	err = w1_add_master_device(master);
+	if (err)
+		return dev_err_probe(dev, err, "w1_add_master device failed\n");
+
+	gpiod_set_value(ddata->pullup_gpiod, 1);
+
+	platform_set_drvdata(pdev, master);
+
+	return 0;
+}
+
+static void w1_gpio_remove(struct platform_device *pdev)
+{
+	struct w1_bus_master *master = platform_get_drvdata(pdev);
+	struct w1_gpio_ddata *ddata = master->data;
+
+	gpiod_set_value(ddata->pullup_gpiod, 0);
+
+	w1_remove_master_device(master);
+}
+
+static const struct of_device_id w1_gpio_dt_ids[] = {
+	{ .compatible = "w1-gpio" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
+
+static struct platform_driver w1_gpio_driver = {
+	.driver = {
+		.name	= "w1-gpio",
+		.of_match_table = w1_gpio_dt_ids,
+	},
+	.probe = w1_gpio_probe,
+	.remove = w1_gpio_remove,
+};
+
+module_platform_driver(w1_gpio_driver);
+
+MODULE_DESCRIPTION("GPIO w1 bus master driver");
+MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
+MODULE_LICENSE("GPL");

linux-7.2.3/drivers/w1/masters/w1-uart.c

@@ -0,0 +1,415 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * w1-uart - UART 1-Wire bus driver
+ *
+ * Uses the UART interface (via Serial Device Bus) to create the 1-Wire
+ * timing patterns. Implements the following 1-Wire master interface:
+ *
+ * - reset_bus: requests baud-rate 9600
+ *
+ * - touch_bit: requests baud-rate 115200
+ *
+ * Author: Christoph Winklhofer <cj.winklhofer@gmail.com>
+ */
+
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/serdev.h>
+#include <linux/w1.h>
+
+/* UART packet contains start and stop bit */
+#define W1_UART_BITS_PER_PACKET (BITS_PER_BYTE + 2)
+
+/* Timeout to wait for completion of serdev-receive */
+#define W1_UART_TIMEOUT msecs_to_jiffies(500)
+
+/**
+ * struct w1_uart_config - configuration for 1-Wire operation
+ * @baudrate: baud-rate returned from serdev
+ * @delay_us: delay to complete a 1-Wire cycle (in us)
+ * @tx_byte: byte to generate 1-Wire timing pattern
+ */
+struct w1_uart_config {
+	unsigned int baudrate;
+	unsigned int delay_us;
+	u8 tx_byte;
+};
+
+/**
+ * struct w1_uart_device - 1-Wire UART device structure
+ * @serdev: serial device
+ * @bus: w1-bus master
+ * @cfg_reset: config for 1-Wire reset
+ * @cfg_touch_0: config for 1-Wire write-0 cycle
+ * @cfg_touch_1: config for 1-Wire write-1 and read cycle
+ * @rx_byte_received: completion for serdev receive
+ * @rx_mutex: mutex to protect rx_err and rx_byte
+ * @rx_err: indicates an error in serdev-receive
+ * @rx_byte: result byte from serdev-receive
+ */
+struct w1_uart_device {
+	struct serdev_device *serdev;
+	struct w1_bus_master bus;
+
+	struct w1_uart_config cfg_reset;
+	struct w1_uart_config cfg_touch_0;
+	struct w1_uart_config cfg_touch_1;
+
+	struct completion rx_byte_received;
+	/*
+	 * protect rx_err and rx_byte from concurrent access in
+	 * w1-callbacks and serdev-receive.
+	 */
+	struct mutex rx_mutex;
+	int rx_err;
+	u8 rx_byte;
+};
+
+/**
+ * struct w1_uart_limits - limits for 1-Wire operations
+ * @baudrate: Requested baud-rate to create 1-Wire timing pattern
+ * @bit_min_us: minimum time for a bit (in us)
+ * @bit_max_us: maximum time for a bit (in us)
+ * @sample_us: timespan to sample 1-Wire response
+ * @cycle_us: duration of the 1-Wire cycle
+ */
+struct w1_uart_limits {
+	unsigned int baudrate;
+	unsigned int bit_min_us;
+	unsigned int bit_max_us;
+	unsigned int sample_us;
+	unsigned int cycle_us;
+};
+
+static inline unsigned int baud_to_bit_ns(unsigned int baud)
+{
+	return NSEC_PER_SEC / baud;
+}
+
+static inline unsigned int to_ns(unsigned int us)
+{
+	return us * NSEC_PER_USEC;
+}
+
+/*
+ * Set baud-rate, delay and tx-byte to create a 1-Wire pulse and adapt
+ * the tx-byte according to the actual baud-rate.
+ *
+ * Reject when:
+ * - time for a bit outside min/max range
+ * - a 1-Wire response is not detectable for sent byte
+ */
+static int w1_uart_set_config(struct serdev_device *serdev,
+			      const struct w1_uart_limits *limits,
+			      struct w1_uart_config *w1cfg)
+{
+	unsigned int packet_ns;
+	unsigned int bits_low;
+	unsigned int bit_ns;
+	unsigned int low_ns;
+
+	w1cfg->baudrate = serdev_device_set_baudrate(serdev, limits->baudrate);
+	if (w1cfg->baudrate == 0)
+		return -EINVAL;
+
+	/* Compute in nanoseconds for accuracy */
+	bit_ns = baud_to_bit_ns(w1cfg->baudrate);
+	bits_low = to_ns(limits->bit_min_us) / bit_ns;
+	/* start bit is always low */
+	low_ns = bit_ns * (bits_low + 1);
+
+	if (low_ns < to_ns(limits->bit_min_us))
+		return -EINVAL;
+
+	if (low_ns > to_ns(limits->bit_max_us))
+		return -EINVAL;
+
+	/* 1-Wire response detectable for sent byte */
+	if (limits->sample_us > 0 &&
+	    bit_ns * BITS_PER_BYTE < low_ns + to_ns(limits->sample_us))
+		return -EINVAL;
+
+	/* delay: 1-Wire cycle takes longer than the UART packet */
+	packet_ns = bit_ns * W1_UART_BITS_PER_PACKET;
+	w1cfg->delay_us = 0;
+	if (to_ns(limits->cycle_us) > packet_ns)
+		w1cfg->delay_us =
+			(to_ns(limits->cycle_us) - packet_ns) / NSEC_PER_USEC;
+
+	/* byte to create 1-Wire pulse */
+	w1cfg->tx_byte = 0xff << bits_low;
+
+	return 0;
+}
+
+/*
+ * Configuration for reset and presence detect
+ * - bit_min_us is 480us, add margin and use 485us
+ * - limits for sample time 60us-75us, use 65us
+ */
+static int w1_uart_set_config_reset(struct w1_uart_device *w1dev)
+{
+	struct serdev_device *serdev = w1dev->serdev;
+	struct device_node *np = serdev->dev.of_node;
+
+	struct w1_uart_limits limits = { .baudrate = 9600,
+					 .bit_min_us = 485,
+					 .bit_max_us = 640,
+					 .sample_us = 65,
+					 .cycle_us = 960 };
+
+	of_property_read_u32(np, "reset-bps", &limits.baudrate);
+
+	return w1_uart_set_config(serdev, &limits, &w1dev->cfg_reset);
+}
+
+/*
+ * Configuration for write-0 cycle (touch bit 0)
+ * - bit_min_us is 60us, add margin and use 65us
+ * - no sampling required, sample_us = 0
+ */
+static int w1_uart_set_config_touch_0(struct w1_uart_device *w1dev)
+{
+	struct serdev_device *serdev = w1dev->serdev;
+	struct device_node *np = serdev->dev.of_node;
+
+	struct w1_uart_limits limits = { .baudrate = 115200,
+					 .bit_min_us = 65,
+					 .bit_max_us = 120,
+					 .sample_us = 0,
+					 .cycle_us = 70 };
+
+	of_property_read_u32(np, "write-0-bps", &limits.baudrate);
+
+	return w1_uart_set_config(serdev, &limits, &w1dev->cfg_touch_0);
+}
+
+/*
+ * Configuration for write-1 and read cycle (touch bit 1)
+ * - bit_min_us is 5us, add margin and use 6us
+ * - limits for sample time 5us-15us, use 15us
+ */
+static int w1_uart_set_config_touch_1(struct w1_uart_device *w1dev)
+{
+	struct serdev_device *serdev = w1dev->serdev;
+	struct device_node *np = serdev->dev.of_node;
+
+	struct w1_uart_limits limits = { .baudrate = 115200,
+					 .bit_min_us = 6,
+					 .bit_max_us = 15,
+					 .sample_us = 15,
+					 .cycle_us = 70 };
+
+	of_property_read_u32(np, "write-1-bps", &limits.baudrate);
+
+	return w1_uart_set_config(serdev, &limits, &w1dev->cfg_touch_1);
+}
+
+/*
+ * Configure and open the serial device
+ */
+static int w1_uart_serdev_open(struct w1_uart_device *w1dev)
+{
+	struct serdev_device *serdev = w1dev->serdev;
+	struct device *dev = &serdev->dev;
+	int ret;
+
+	ret = devm_serdev_device_open(dev, serdev);
+	if (ret < 0)
+		return ret;
+
+	ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
+	if (ret < 0) {
+		dev_err(dev, "set parity failed\n");
+		return ret;
+	}
+
+	ret = w1_uart_set_config_reset(w1dev);
+	if (ret < 0) {
+		dev_err(dev, "config for reset failed\n");
+		return ret;
+	}
+
+	ret = w1_uart_set_config_touch_0(w1dev);
+	if (ret < 0) {
+		dev_err(dev, "config for touch-0 failed\n");
+		return ret;
+	}
+
+	ret = w1_uart_set_config_touch_1(w1dev);
+	if (ret < 0) {
+		dev_err(dev, "config for touch-1 failed\n");
+		return ret;
+	}
+
+	serdev_device_set_flow_control(serdev, false);
+
+	return 0;
+}
+
+/*
+ * Send one byte (tx_byte) and read one byte (rx_byte) via serdev.
+ */
+static int w1_uart_serdev_tx_rx(struct w1_uart_device *w1dev,
+				const struct w1_uart_config *w1cfg, u8 *rx_byte)
+{
+	struct serdev_device *serdev = w1dev->serdev;
+	int ret;
+
+	serdev_device_write_flush(serdev);
+	serdev_device_set_baudrate(serdev, w1cfg->baudrate);
+
+	/* write and immediately read one byte */
+	reinit_completion(&w1dev->rx_byte_received);
+	ret = serdev_device_write_buf(serdev, &w1cfg->tx_byte, 1);
+	if (ret != 1)
+		return -EIO;
+	ret = wait_for_completion_interruptible_timeout(
+		&w1dev->rx_byte_received, W1_UART_TIMEOUT);
+	if (ret <= 0)
+		return -EIO;
+
+	/* locking could fail when serdev is unexpectedly receiving. */
+	if (!mutex_trylock(&w1dev->rx_mutex))
+		return -EIO;
+
+	ret = w1dev->rx_err;
+	if (ret == 0)
+		*rx_byte = w1dev->rx_byte;
+
+	mutex_unlock(&w1dev->rx_mutex);
+
+	if (w1cfg->delay_us > 0)
+		fsleep(w1cfg->delay_us);
+
+	return ret;
+}
+
+static size_t w1_uart_serdev_receive_buf(struct serdev_device *serdev,
+					  const u8 *buf, size_t count)
+{
+	struct w1_uart_device *w1dev = serdev_device_get_drvdata(serdev);
+
+	mutex_lock(&w1dev->rx_mutex);
+
+	/* sent a single byte and receive one single byte */
+	if (count == 1) {
+		w1dev->rx_byte = buf[0];
+		w1dev->rx_err = 0;
+	} else {
+		w1dev->rx_err = -EIO;
+	}
+
+	mutex_unlock(&w1dev->rx_mutex);
+	complete(&w1dev->rx_byte_received);
+
+	return count;
+}
+
+static const struct serdev_device_ops w1_uart_serdev_ops = {
+	.receive_buf = w1_uart_serdev_receive_buf,
+	.write_wakeup = serdev_device_write_wakeup,
+};
+
+/*
+ * 1-wire reset and presence detect: A present slave will manipulate
+ * the received byte by pulling the 1-Wire low.
+ */
+static u8 w1_uart_reset_bus(void *data)
+{
+	struct w1_uart_device *w1dev = data;
+	const struct w1_uart_config *w1cfg = &w1dev->cfg_reset;
+	int ret;
+	u8 val;
+
+	ret = w1_uart_serdev_tx_rx(w1dev, w1cfg, &val);
+	if (ret < 0)
+		return -1;
+
+	/* Device present (0) or no device (1) */
+	return val != w1cfg->tx_byte ? 0 : 1;
+}
+
+/*
+ * 1-Wire read and write cycle: Only the read-0 manipulates the
+ * received byte, all others left the line untouched.
+ */
+static u8 w1_uart_touch_bit(void *data, u8 bit)
+{
+	struct w1_uart_device *w1dev = data;
+	const struct w1_uart_config *w1cfg = bit ? &w1dev->cfg_touch_1 :
+						   &w1dev->cfg_touch_0;
+	int ret;
+	u8 val;
+
+	ret = w1_uart_serdev_tx_rx(w1dev, w1cfg, &val);
+
+	/* return inactive bus state on error */
+	if (ret < 0)
+		return 1;
+
+	return val == w1cfg->tx_byte ? 1 : 0;
+}
+
+static int w1_uart_probe(struct serdev_device *serdev)
+{
+	struct device *dev = &serdev->dev;
+	struct w1_uart_device *w1dev;
+	int ret;
+
+	w1dev = devm_kzalloc(dev, sizeof(*w1dev), GFP_KERNEL);
+	if (!w1dev)
+		return -ENOMEM;
+	w1dev->bus.data = w1dev;
+	w1dev->bus.reset_bus = w1_uart_reset_bus;
+	w1dev->bus.touch_bit = w1_uart_touch_bit;
+	w1dev->serdev = serdev;
+
+	init_completion(&w1dev->rx_byte_received);
+	mutex_init(&w1dev->rx_mutex);
+
+	serdev_device_set_drvdata(serdev, w1dev);
+	serdev_device_set_client_ops(serdev, &w1_uart_serdev_ops);
+	ret = w1_uart_serdev_open(w1dev);
+	if (ret < 0)
+		return ret;
+
+	return w1_add_master_device(&w1dev->bus);
+}
+
+static void w1_uart_remove(struct serdev_device *serdev)
+{
+	struct w1_uart_device *w1dev = serdev_device_get_drvdata(serdev);
+
+	/*
+	 * Waits until w1-uart callbacks are finished, serdev is closed
+	 * and its device data released automatically by devres (waits
+	 * until serdev-receive is finished).
+	 */
+	w1_remove_master_device(&w1dev->bus);
+}
+
+static const struct of_device_id w1_uart_of_match[] = {
+	{ .compatible = "w1-uart" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, w1_uart_of_match);
+
+static struct serdev_device_driver w1_uart_driver = {
+	.driver	= {
+		.name		= "w1-uart",
+		.of_match_table = w1_uart_of_match,
+	},
+	.probe	= w1_uart_probe,
+	.remove	= w1_uart_remove,
+};
+
+module_serdev_device_driver(w1_uart_driver);
+
+MODULE_DESCRIPTION("UART w1 bus driver");
+MODULE_AUTHOR("Christoph Winklhofer <cj.winklhofer@gmail.com>");
+MODULE_LICENSE("GPL");