drivers/i2c/busses/i2c-amd-mp2-plat.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
  * AMD MP2 platform driver
  *
  * Setup the I2C adapters enumerated in the ACPI namespace.
  * MP2 controllers have 2 separate busses, up to 2 I2C adapters may be listed.
  *
  * Authors: Nehal Bakulchandra Shah <Nehal-bakulchandra.shah@amd.com>
  *          Elie Morisse <syniurge@gmail.com>
  */

 #include <linux/acpi.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/types.h>

 #include "i2c-amd-mp2.h"

 #define AMD_MP2_I2C_MAX_RW_LENGTH ((1 << 12) - 1)
 #define AMD_I2C_TIMEOUT (msecs_to_jiffies(250))

 /**
  * struct amd_i2c_dev - MP2 bus/i2c adapter context
  * @common: shared context with the MP2 PCI driver
  * @pdev: platform driver node
  * @adap: i2c adapter
  * @cmd_complete: xfer completion object
  */
 struct amd_i2c_dev {
 	struct amd_i2c_common common;
 	struct platform_device *pdev;
 	struct i2c_adapter adap;
 	struct completion cmd_complete;
 };

 #define amd_i2c_dev_common(__common) \
 	container_of(__common, struct amd_i2c_dev, common)

 static int i2c_amd_dma_map(struct amd_i2c_common *i2c_common)
 {
 	struct device *dev_pci = &i2c_common->mp2_dev->pci_dev->dev;
 	struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
 	enum dma_data_direction dma_direction =
 			i2c_common->msg->flags & I2C_M_RD ?
 			DMA_FROM_DEVICE : DMA_TO_DEVICE;

 	i2c_common->dma_buf = i2c_get_dma_safe_msg_buf(i2c_common->msg, 0);
 	i2c_common->dma_addr = dma_map_single(dev_pci, i2c_common->dma_buf,
 					      i2c_common->msg->len,
 					      dma_direction);

 	if (unlikely(dma_mapping_error(dev_pci, i2c_common->dma_addr))) {
 		dev_err(&i2c_dev->pdev->dev,
 			"Error while mapping dma buffer %p\n",
 			i2c_common->dma_buf);
 		return -EIO;
 	}

 	return 0;
 }

 static void i2c_amd_dma_unmap(struct amd_i2c_common *i2c_common)
 {
 	struct device *dev_pci = &i2c_common->mp2_dev->pci_dev->dev;
 	enum dma_data_direction dma_direction =
 			i2c_common->msg->flags & I2C_M_RD ?
 			DMA_FROM_DEVICE : DMA_TO_DEVICE;

 	dma_unmap_single(dev_pci, i2c_common->dma_addr,
 			 i2c_common->msg->len, dma_direction);

 	i2c_put_dma_safe_msg_buf(i2c_common->dma_buf, i2c_common->msg, true);
 }

 static void i2c_amd_start_cmd(struct amd_i2c_dev *i2c_dev)
 {
 	struct amd_i2c_common *i2c_common = &i2c_dev->common;

 	reinit_completion(&i2c_dev->cmd_complete);
 	i2c_common->cmd_success = false;
 }

 static void i2c_amd_cmd_completion(struct amd_i2c_common *i2c_common)
 {
 	struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
 	union i2c_event *event = &i2c_common->eventval;

 	if (event->r.status == i2c_readcomplete_event)
 		dev_dbg(&i2c_dev->pdev->dev, "readdata:%*ph\n", event->r.length,
 			i2c_common->msg->buf);

 	complete(&i2c_dev->cmd_complete);
 }

 static int i2c_amd_check_cmd_completion(struct amd_i2c_dev *i2c_dev)
 {
 	struct amd_i2c_common *i2c_common = &i2c_dev->common;
 	unsigned long timeout;

 	timeout = wait_for_completion_timeout(&i2c_dev->cmd_complete,
 					      i2c_dev->adap.timeout);

 	if ((i2c_common->reqcmd == i2c_read ||
 	     i2c_common->reqcmd == i2c_write) &&
 	    i2c_common->msg->len > 32)
 		i2c_amd_dma_unmap(i2c_common);

 	if (timeout == 0) {
 		amd_mp2_rw_timeout(i2c_common);
 		return -ETIMEDOUT;
 	}

 	amd_mp2_process_event(i2c_common);

 	if (!i2c_common->cmd_success)
 		return -EIO;

 	return 0;
 }

 static int i2c_amd_enable_set(struct amd_i2c_dev *i2c_dev, bool enable)
 {
 	struct amd_i2c_common *i2c_common = &i2c_dev->common;

 	i2c_amd_start_cmd(i2c_dev);
 	amd_mp2_bus_enable_set(i2c_common, enable);

 	return i2c_amd_check_cmd_completion(i2c_dev);
 }

 static int i2c_amd_xfer_msg(struct amd_i2c_dev *i2c_dev, struct i2c_msg *pmsg)
 {
 	struct amd_i2c_common *i2c_common = &i2c_dev->common;

 	i2c_amd_start_cmd(i2c_dev);
 	i2c_common->msg = pmsg;

 	if (pmsg->len > 32)
 		if (i2c_amd_dma_map(i2c_common))
 			return -EIO;

 	if (pmsg->flags & I2C_M_RD)
 		amd_mp2_rw(i2c_common, i2c_read);
 	else
 		amd_mp2_rw(i2c_common, i2c_write);

 	return i2c_amd_check_cmd_completion(i2c_dev);
 }

 static int i2c_amd_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 {
 	struct amd_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
 	int i;
 	struct i2c_msg *pmsg;
 	int err = 0;

 	/* the adapter might have been deleted while waiting for the bus lock */
 	if (unlikely(!i2c_dev->common.mp2_dev))
 		return -EINVAL;

 	amd_mp2_pm_runtime_get(i2c_dev->common.mp2_dev);

 	for (i = 0; i < num; i++) {
 		pmsg = &msgs[i];
 		err = i2c_amd_xfer_msg(i2c_dev, pmsg);
 		if (err)
 			break;
 	}

 	amd_mp2_pm_runtime_put(i2c_dev->common.mp2_dev);
 	return err ? err : num;
 }

 static u32 i2c_amd_func(struct i2c_adapter *a)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }

 static const struct i2c_algorithm i2c_amd_algorithm = {
 	.master_xfer = i2c_amd_xfer,
 	.functionality = i2c_amd_func,
 };

 #ifdef CONFIG_PM
 static int i2c_amd_suspend(struct amd_i2c_common *i2c_common)
 {
 	struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);

 	i2c_amd_enable_set(i2c_dev, false);
 	return 0;
 }

 static int i2c_amd_resume(struct amd_i2c_common *i2c_common)
 {
 	struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);

 	return i2c_amd_enable_set(i2c_dev, true);
 }
 #endif

 static const u32 supported_speeds[] = {
 	I2C_MAX_HIGH_SPEED_MODE_FREQ,
 	I2C_MAX_TURBO_MODE_FREQ,
 	I2C_MAX_FAST_MODE_PLUS_FREQ,
 	I2C_MAX_FAST_MODE_FREQ,
 	I2C_MAX_STANDARD_MODE_FREQ,
 };

 static enum speed_enum i2c_amd_get_bus_speed(struct platform_device *pdev)
 {
 	u32 acpi_speed;
 	int i;

 	acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
 	/* round down to the lowest standard speed */
 	for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) {
 		if (acpi_speed >= supported_speeds[i])
 			break;
 	}
 	acpi_speed = i < ARRAY_SIZE(supported_speeds) ? supported_speeds[i] : 0;

 	switch (acpi_speed) {
 	case I2C_MAX_STANDARD_MODE_FREQ:
 		return speed100k;
 	case I2C_MAX_FAST_MODE_FREQ:
 		return speed400k;
 	case I2C_MAX_FAST_MODE_PLUS_FREQ:
 		return speed1000k;
 	case I2C_MAX_TURBO_MODE_FREQ:
 		return speed1400k;
 	case I2C_MAX_HIGH_SPEED_MODE_FREQ:
 		return speed3400k;
 	default:
 		return speed400k;
 	}
 }

 static const struct i2c_adapter_quirks amd_i2c_dev_quirks = {
 	.max_read_len = AMD_MP2_I2C_MAX_RW_LENGTH,
 	.max_write_len = AMD_MP2_I2C_MAX_RW_LENGTH,
 };

 static int i2c_amd_probe(struct platform_device *pdev)
 {
 	int ret;
 	struct amd_i2c_dev *i2c_dev;
 	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
 	struct amd_mp2_dev *mp2_dev;
 	const char *uid;

 	if (!adev)
 		return -ENODEV;

 	/* The ACPI namespace doesn't contain information about which MP2 PCI
 	 * device an AMDI0011 ACPI device is related to, so assume that there's
 	 * only one MP2 PCI device per system.
 	 */
 	mp2_dev = amd_mp2_find_device();
 	if (!mp2_dev || !mp2_dev->probed)
 		/* The MP2 PCI device should get probed later */
 		return -EPROBE_DEFER;

 	i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
 	if (!i2c_dev)
 		return -ENOMEM;

 	i2c_dev->common.mp2_dev = mp2_dev;
 	i2c_dev->pdev = pdev;
 	platform_set_drvdata(pdev, i2c_dev);

 	i2c_dev->common.cmd_completion = &i2c_amd_cmd_completion;
 #ifdef CONFIG_PM
 	i2c_dev->common.suspend = &i2c_amd_suspend;
 	i2c_dev->common.resume = &i2c_amd_resume;
 #endif

 	uid = adev->pnp.unique_id;
 	if (!uid) {
 		dev_err(&pdev->dev, "missing UID/bus id!\n");
 		return -EINVAL;
 	} else if (strcmp(uid, "0") == 0) {
 		i2c_dev->common.bus_id = 0;
 	} else if (strcmp(uid, "1") == 0) {
 		i2c_dev->common.bus_id = 1;
 	} else {
 		dev_err(&pdev->dev, "incorrect UID/bus id \"%s\"!\n", uid);
 		return -EINVAL;
 	}
 	dev_dbg(&pdev->dev, "bus id is %u\n", i2c_dev->common.bus_id);

 	/* Register the adapter */
 	amd_mp2_pm_runtime_get(mp2_dev);

 	i2c_dev->common.reqcmd = i2c_none;
 	if (amd_mp2_register_cb(&i2c_dev->common))
 		return -EINVAL;
 	device_link_add(&i2c_dev->pdev->dev, &mp2_dev->pci_dev->dev,
 			DL_FLAG_AUTOREMOVE_CONSUMER);

 	i2c_dev->common.i2c_speed = i2c_amd_get_bus_speed(pdev);

 	/* Setup i2c adapter description */
 	i2c_dev->adap.owner = THIS_MODULE;
 	i2c_dev->adap.algo = &i2c_amd_algorithm;
 	i2c_dev->adap.quirks = &amd_i2c_dev_quirks;
 	i2c_dev->adap.dev.parent = &pdev->dev;
 	i2c_dev->adap.algo_data = i2c_dev;
 	i2c_dev->adap.timeout = AMD_I2C_TIMEOUT;
 	ACPI_COMPANION_SET(&i2c_dev->adap.dev, ACPI_COMPANION(&pdev->dev));
 	i2c_dev->adap.dev.of_node = pdev->dev.of_node;
 	snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
 		 "AMD MP2 i2c bus %u", i2c_dev->common.bus_id);
 	i2c_set_adapdata(&i2c_dev->adap, i2c_dev);

 	init_completion(&i2c_dev->cmd_complete);

 	/* Enable the bus */
 	if (i2c_amd_enable_set(i2c_dev, true))
 		dev_err(&pdev->dev, "initial bus enable failed\n");

 	/* Attach to the i2c layer */
 	ret = i2c_add_adapter(&i2c_dev->adap);

 	amd_mp2_pm_runtime_put(mp2_dev);

 	if (ret < 0)
 		dev_err(&pdev->dev, "i2c add adapter failed = %d\n", ret);

 	return ret;
 }

 static int i2c_amd_remove(struct platform_device *pdev)
 {
 	struct amd_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 	struct amd_i2c_common *i2c_common = &i2c_dev->common;

 	i2c_lock_bus(&i2c_dev->adap, I2C_LOCK_ROOT_ADAPTER);

 	i2c_amd_enable_set(i2c_dev, false);
 	amd_mp2_unregister_cb(i2c_common);
 	i2c_common->mp2_dev = NULL;

 	i2c_unlock_bus(&i2c_dev->adap, I2C_LOCK_ROOT_ADAPTER);

 	i2c_del_adapter(&i2c_dev->adap);
 	return 0;
 }

 static const struct acpi_device_id i2c_amd_acpi_match[] = {
 	{ "AMDI0011" },
 	{ },
 };
 MODULE_DEVICE_TABLE(acpi, i2c_amd_acpi_match);

 static struct platform_driver i2c_amd_plat_driver = {
 	.probe = i2c_amd_probe,
 	.remove = i2c_amd_remove,
 	.driver = {
 		.name = "i2c_amd_mp2",
 		.acpi_match_table = ACPI_PTR(i2c_amd_acpi_match),
 	},
 };
 module_platform_driver(i2c_amd_plat_driver);

 MODULE_DESCRIPTION("AMD(R) MP2 I2C Platform Driver");
 MODULE_AUTHOR("Nehal Shah <nehal-bakulchandra.shah@amd.com>");
 MODULE_AUTHOR("Elie Morisse <syniurge@gmail.com>");
 MODULE_LICENSE("Dual BSD/GPL");
	// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
	/*
	* AMD MP2 platform driver
	*
	* Setup the I2C adapters enumerated in the ACPI namespace.
	* MP2 controllers have 2 separate busses, up to 2 I2C adapters may be listed.
	*
	* Authors: Nehal Bakulchandra Shah <Nehal-bakulchandra.shah@amd.com>
	* Elie Morisse <syniurge@gmail.com>
	*/

	#include <linux/acpi.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <linux/types.h>

	#include "i2c-amd-mp2.h"

	#define AMD_MP2_I2C_MAX_RW_LENGTH ((1 << 12) - 1)
	#define AMD_I2C_TIMEOUT (msecs_to_jiffies(250))

	/**
	* struct amd_i2c_dev - MP2 bus/i2c adapter context
	* @common: shared context with the MP2 PCI driver
	* @pdev: platform driver node
	* @adap: i2c adapter
	* @cmd_complete: xfer completion object
	*/
	struct amd_i2c_dev {
	struct amd_i2c_common common;
	struct platform_device *pdev;
	struct i2c_adapter adap;
	struct completion cmd_complete;
	};

	#define amd_i2c_dev_common(__common) \
	container_of(__common, struct amd_i2c_dev, common)

	static int i2c_amd_dma_map(struct amd_i2c_common *i2c_common)
	{
	struct device *dev_pci = &i2c_common->mp2_dev->pci_dev->dev;
	struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
	enum dma_data_direction dma_direction =
	i2c_common->msg->flags & I2C_M_RD ?
	DMA_FROM_DEVICE : DMA_TO_DEVICE;

	i2c_common->dma_buf = i2c_get_dma_safe_msg_buf(i2c_common->msg, 0);
	i2c_common->dma_addr = dma_map_single(dev_pci, i2c_common->dma_buf,
	i2c_common->msg->len,
	dma_direction);

	if (unlikely(dma_mapping_error(dev_pci, i2c_common->dma_addr))) {
	dev_err(&i2c_dev->pdev->dev,
	"Error while mapping dma buffer %p\n",
	i2c_common->dma_buf);
	return -EIO;
	}

	return 0;
	}

	static void i2c_amd_dma_unmap(struct amd_i2c_common *i2c_common)
	{
	struct device *dev_pci = &i2c_common->mp2_dev->pci_dev->dev;
	enum dma_data_direction dma_direction =
	i2c_common->msg->flags & I2C_M_RD ?
	DMA_FROM_DEVICE : DMA_TO_DEVICE;

	dma_unmap_single(dev_pci, i2c_common->dma_addr,
	i2c_common->msg->len, dma_direction);

	i2c_put_dma_safe_msg_buf(i2c_common->dma_buf, i2c_common->msg, true);
	}

	static void i2c_amd_start_cmd(struct amd_i2c_dev *i2c_dev)
	{
	struct amd_i2c_common *i2c_common = &i2c_dev->common;

	reinit_completion(&i2c_dev->cmd_complete);
	i2c_common->cmd_success = false;
	}

	static void i2c_amd_cmd_completion(struct amd_i2c_common *i2c_common)
	{
	struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);
	union i2c_event *event = &i2c_common->eventval;

	if (event->r.status == i2c_readcomplete_event)
	dev_dbg(&i2c_dev->pdev->dev, "readdata:%*ph\n", event->r.length,
	i2c_common->msg->buf);

	complete(&i2c_dev->cmd_complete);
	}

	static int i2c_amd_check_cmd_completion(struct amd_i2c_dev *i2c_dev)
	{
	struct amd_i2c_common *i2c_common = &i2c_dev->common;
	unsigned long timeout;

	timeout = wait_for_completion_timeout(&i2c_dev->cmd_complete,
	i2c_dev->adap.timeout);

	if ((i2c_common->reqcmd == i2c_read \|\|
	i2c_common->reqcmd == i2c_write) &&
	i2c_common->msg->len > 32)
	i2c_amd_dma_unmap(i2c_common);

	if (timeout == 0) {
	amd_mp2_rw_timeout(i2c_common);
	return -ETIMEDOUT;
	}

	amd_mp2_process_event(i2c_common);

	if (!i2c_common->cmd_success)
	return -EIO;

	return 0;
	}

	static int i2c_amd_enable_set(struct amd_i2c_dev *i2c_dev, bool enable)
	{
	struct amd_i2c_common *i2c_common = &i2c_dev->common;

	i2c_amd_start_cmd(i2c_dev);
	amd_mp2_bus_enable_set(i2c_common, enable);

	return i2c_amd_check_cmd_completion(i2c_dev);
	}

	static int i2c_amd_xfer_msg(struct amd_i2c_dev i2c_dev, struct i2c_msg pmsg)
	{
	struct amd_i2c_common *i2c_common = &i2c_dev->common;

	i2c_amd_start_cmd(i2c_dev);
	i2c_common->msg = pmsg;

	if (pmsg->len > 32)
	if (i2c_amd_dma_map(i2c_common))
	return -EIO;

	if (pmsg->flags & I2C_M_RD)
	amd_mp2_rw(i2c_common, i2c_read);
	else
	amd_mp2_rw(i2c_common, i2c_write);

	return i2c_amd_check_cmd_completion(i2c_dev);
	}

	static int i2c_amd_xfer(struct i2c_adapter adap, struct i2c_msg msgs, int num)
	{
	struct amd_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
	int i;
	struct i2c_msg *pmsg;
	int err = 0;

	/* the adapter might have been deleted while waiting for the bus lock */
	if (unlikely(!i2c_dev->common.mp2_dev))
	return -EINVAL;

	amd_mp2_pm_runtime_get(i2c_dev->common.mp2_dev);

	for (i = 0; i < num; i++) {
	pmsg = &msgs[i];
	err = i2c_amd_xfer_msg(i2c_dev, pmsg);
	if (err)
	break;
	}

	amd_mp2_pm_runtime_put(i2c_dev->common.mp2_dev);
	return err ? err : num;
	}

	static u32 i2c_amd_func(struct i2c_adapter *a)
	{
	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL;
	}

	static const struct i2c_algorithm i2c_amd_algorithm = {
	.master_xfer = i2c_amd_xfer,
	.functionality = i2c_amd_func,
	};

	#ifdef CONFIG_PM
	static int i2c_amd_suspend(struct amd_i2c_common *i2c_common)
	{
	struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);

	i2c_amd_enable_set(i2c_dev, false);
	return 0;
	}

	static int i2c_amd_resume(struct amd_i2c_common *i2c_common)
	{
	struct amd_i2c_dev *i2c_dev = amd_i2c_dev_common(i2c_common);

	return i2c_amd_enable_set(i2c_dev, true);
	}
	#endif

	static const u32 supported_speeds[] = {
	I2C_MAX_HIGH_SPEED_MODE_FREQ,
	I2C_MAX_TURBO_MODE_FREQ,
	I2C_MAX_FAST_MODE_PLUS_FREQ,
	I2C_MAX_FAST_MODE_FREQ,
	I2C_MAX_STANDARD_MODE_FREQ,
	};

	static enum speed_enum i2c_amd_get_bus_speed(struct platform_device *pdev)
	{
	u32 acpi_speed;
	int i;

	acpi_speed = i2c_acpi_find_bus_speed(&pdev->dev);
	/* round down to the lowest standard speed */
	for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) {
	if (acpi_speed >= supported_speeds[i])
	break;
	}
	acpi_speed = i < ARRAY_SIZE(supported_speeds) ? supported_speeds[i] : 0;

	switch (acpi_speed) {
	case I2C_MAX_STANDARD_MODE_FREQ:
	return speed100k;
	case I2C_MAX_FAST_MODE_FREQ:
	return speed400k;
	case I2C_MAX_FAST_MODE_PLUS_FREQ:
	return speed1000k;
	case I2C_MAX_TURBO_MODE_FREQ:
	return speed1400k;
	case I2C_MAX_HIGH_SPEED_MODE_FREQ:
	return speed3400k;
	default:
	return speed400k;
	}
	}

	static const struct i2c_adapter_quirks amd_i2c_dev_quirks = {
	.max_read_len = AMD_MP2_I2C_MAX_RW_LENGTH,
	.max_write_len = AMD_MP2_I2C_MAX_RW_LENGTH,
	};

	static int i2c_amd_probe(struct platform_device *pdev)
	{
	int ret;
	struct amd_i2c_dev *i2c_dev;
	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
	struct amd_mp2_dev *mp2_dev;
	const char *uid;

	if (!adev)
	return -ENODEV;

	/* The ACPI namespace doesn't contain information about which MP2 PCI
	* device an AMDI0011 ACPI device is related to, so assume that there's
	* only one MP2 PCI device per system.
	*/
	mp2_dev = amd_mp2_find_device();
	if (!mp2_dev \|\| !mp2_dev->probed)
	/* The MP2 PCI device should get probed later */
	return -EPROBE_DEFER;

	i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
	if (!i2c_dev)
	return -ENOMEM;

	i2c_dev->common.mp2_dev = mp2_dev;
	i2c_dev->pdev = pdev;
	platform_set_drvdata(pdev, i2c_dev);

	i2c_dev->common.cmd_completion = &i2c_amd_cmd_completion;
	#ifdef CONFIG_PM
	i2c_dev->common.suspend = &i2c_amd_suspend;
	i2c_dev->common.resume = &i2c_amd_resume;
	#endif

	uid = adev->pnp.unique_id;
	if (!uid) {
	dev_err(&pdev->dev, "missing UID/bus id!\n");
	return -EINVAL;
	} else if (strcmp(uid, "0") == 0) {
	i2c_dev->common.bus_id = 0;
	} else if (strcmp(uid, "1") == 0) {
	i2c_dev->common.bus_id = 1;
	} else {
	dev_err(&pdev->dev, "incorrect UID/bus id \"%s\"!\n", uid);
	return -EINVAL;
	}
	dev_dbg(&pdev->dev, "bus id is %u\n", i2c_dev->common.bus_id);

	/* Register the adapter */
	amd_mp2_pm_runtime_get(mp2_dev);

	i2c_dev->common.reqcmd = i2c_none;
	if (amd_mp2_register_cb(&i2c_dev->common))
	return -EINVAL;
	device_link_add(&i2c_dev->pdev->dev, &mp2_dev->pci_dev->dev,
	DL_FLAG_AUTOREMOVE_CONSUMER);

	i2c_dev->common.i2c_speed = i2c_amd_get_bus_speed(pdev);

	/* Setup i2c adapter description */
	i2c_dev->adap.owner = THIS_MODULE;
	i2c_dev->adap.algo = &i2c_amd_algorithm;
	i2c_dev->adap.quirks = &amd_i2c_dev_quirks;
	i2c_dev->adap.dev.parent = &pdev->dev;
	i2c_dev->adap.algo_data = i2c_dev;
	i2c_dev->adap.timeout = AMD_I2C_TIMEOUT;
	ACPI_COMPANION_SET(&i2c_dev->adap.dev, ACPI_COMPANION(&pdev->dev));
	i2c_dev->adap.dev.of_node = pdev->dev.of_node;
	snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
	"AMD MP2 i2c bus %u", i2c_dev->common.bus_id);
	i2c_set_adapdata(&i2c_dev->adap, i2c_dev);

	init_completion(&i2c_dev->cmd_complete);

	/* Enable the bus */
	if (i2c_amd_enable_set(i2c_dev, true))
	dev_err(&pdev->dev, "initial bus enable failed\n");

	/* Attach to the i2c layer */
	ret = i2c_add_adapter(&i2c_dev->adap);

	amd_mp2_pm_runtime_put(mp2_dev);

	if (ret < 0)
	dev_err(&pdev->dev, "i2c add adapter failed = %d\n", ret);

	return ret;
	}

	static int i2c_amd_remove(struct platform_device *pdev)
	{
	struct amd_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
	struct amd_i2c_common *i2c_common = &i2c_dev->common;

	i2c_lock_bus(&i2c_dev->adap, I2C_LOCK_ROOT_ADAPTER);

	i2c_amd_enable_set(i2c_dev, false);
	amd_mp2_unregister_cb(i2c_common);
	i2c_common->mp2_dev = NULL;

	i2c_unlock_bus(&i2c_dev->adap, I2C_LOCK_ROOT_ADAPTER);

	i2c_del_adapter(&i2c_dev->adap);
	return 0;
	}

	static const struct acpi_device_id i2c_amd_acpi_match[] = {
	{ "AMDI0011" },
	{ },
	};
	MODULE_DEVICE_TABLE(acpi, i2c_amd_acpi_match);

	static struct platform_driver i2c_amd_plat_driver = {
	.probe = i2c_amd_probe,
	.remove = i2c_amd_remove,
	.driver = {
	.name = "i2c_amd_mp2",
	.acpi_match_table = ACPI_PTR(i2c_amd_acpi_match),
	},
	};
	module_platform_driver(i2c_amd_plat_driver);

	MODULE_DESCRIPTION("AMD(R) MP2 I2C Platform Driver");
	MODULE_AUTHOR("Nehal Shah <nehal-bakulchandra.shah@amd.com>");
	MODULE_AUTHOR("Elie Morisse <syniurge@gmail.com>");
	MODULE_LICENSE("Dual BSD/GPL");