drivers/i2c/busses/i2c-nvidia-gpu.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Nvidia GPU I2C controller Driver
  *
  * Copyright (C) 2018 NVIDIA Corporation. All rights reserved.
  * Author: Ajay Gupta <ajayg@nvidia.com>
  */
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>

 #include <asm/unaligned.h>

 /* I2C definitions */
 #define I2C_MST_CNTL				0x00
 #define I2C_MST_CNTL_GEN_START			BIT(0)
 #define I2C_MST_CNTL_GEN_STOP			BIT(1)
 #define I2C_MST_CNTL_CMD_READ			(1 << 2)
 #define I2C_MST_CNTL_CMD_WRITE			(2 << 2)
 #define I2C_MST_CNTL_BURST_SIZE_SHIFT		6
 #define I2C_MST_CNTL_GEN_NACK			BIT(28)
 #define I2C_MST_CNTL_STATUS			GENMASK(30, 29)
 #define I2C_MST_CNTL_STATUS_OKAY		(0 << 29)
 #define I2C_MST_CNTL_STATUS_NO_ACK		(1 << 29)
 #define I2C_MST_CNTL_STATUS_TIMEOUT		(2 << 29)
 #define I2C_MST_CNTL_STATUS_BUS_BUSY		(3 << 29)
 #define I2C_MST_CNTL_CYCLE_TRIGGER		BIT(31)

 #define I2C_MST_ADDR				0x04

 #define I2C_MST_I2C0_TIMING				0x08
 #define I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ		0x10e
 #define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT		16
 #define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX		255
 #define I2C_MST_I2C0_TIMING_TIMEOUT_CHECK		BIT(24)

 #define I2C_MST_DATA					0x0c

 #define I2C_MST_HYBRID_PADCTL				0x20
 #define I2C_MST_HYBRID_PADCTL_MODE_I2C			BIT(0)
 #define I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV		BIT(14)
 #define I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV		BIT(15)

 struct gpu_i2c_dev {
 	struct device *dev;
 	void __iomem *regs;
 	struct i2c_adapter adapter;
 	struct i2c_board_info *gpu_ccgx_ucsi;
 	struct i2c_client *ccgx_client;
 };

 static void gpu_enable_i2c_bus(struct gpu_i2c_dev *i2cd)
 {
 	u32 val;

 	/* enable I2C */
 	val = readl(i2cd->regs + I2C_MST_HYBRID_PADCTL);
 	val |= I2C_MST_HYBRID_PADCTL_MODE_I2C |
 		I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV |
 		I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV;
 	writel(val, i2cd->regs + I2C_MST_HYBRID_PADCTL);

 	/* enable 100KHZ mode */
 	val = I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ;
 	val |= (I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX
 	    << I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT);
 	val |= I2C_MST_I2C0_TIMING_TIMEOUT_CHECK;
 	writel(val, i2cd->regs + I2C_MST_I2C0_TIMING);
 }

 static int gpu_i2c_check_status(struct gpu_i2c_dev *i2cd)
 {
 	u32 val;
 	int ret;

 	ret = readl_poll_timeout(i2cd->regs + I2C_MST_CNTL, val,
 				 !(val & I2C_MST_CNTL_CYCLE_TRIGGER) ||
 				 (val & I2C_MST_CNTL_STATUS) != I2C_MST_CNTL_STATUS_BUS_BUSY,
 				 500, 1000 * USEC_PER_MSEC);

 	if (ret) {
 		dev_err(i2cd->dev, "i2c timeout error %x\n", val);
 		return -ETIMEDOUT;
 	}

 	val = readl(i2cd->regs + I2C_MST_CNTL);
 	switch (val & I2C_MST_CNTL_STATUS) {
 	case I2C_MST_CNTL_STATUS_OKAY:
 		return 0;
 	case I2C_MST_CNTL_STATUS_NO_ACK:
 		return -ENXIO;
 	case I2C_MST_CNTL_STATUS_TIMEOUT:
 		return -ETIMEDOUT;
 	default:
 		return 0;
 	}
 }

 static int gpu_i2c_read(struct gpu_i2c_dev *i2cd, u8 *data, u16 len)
 {
 	int status;
 	u32 val;

 	val = I2C_MST_CNTL_GEN_START | I2C_MST_CNTL_CMD_READ |
 		(len << I2C_MST_CNTL_BURST_SIZE_SHIFT) |
 		I2C_MST_CNTL_CYCLE_TRIGGER | I2C_MST_CNTL_GEN_NACK;
 	writel(val, i2cd->regs + I2C_MST_CNTL);

 	status = gpu_i2c_check_status(i2cd);
 	if (status < 0)
 		return status;

 	val = readl(i2cd->regs + I2C_MST_DATA);
 	switch (len) {
 	case 1:
 		data[0] = val;
 		break;
 	case 2:
 		put_unaligned_be16(val, data);
 		break;
 	case 3:
 		put_unaligned_be24(val, data);
 		break;
 	case 4:
 		put_unaligned_be32(val, data);
 		break;
 	default:
 		break;
 	}
 	return status;
 }

 static int gpu_i2c_start(struct gpu_i2c_dev *i2cd)
 {
 	writel(I2C_MST_CNTL_GEN_START, i2cd->regs + I2C_MST_CNTL);
 	return gpu_i2c_check_status(i2cd);
 }

 static int gpu_i2c_stop(struct gpu_i2c_dev *i2cd)
 {
 	writel(I2C_MST_CNTL_GEN_STOP, i2cd->regs + I2C_MST_CNTL);
 	return gpu_i2c_check_status(i2cd);
 }

 static int gpu_i2c_write(struct gpu_i2c_dev *i2cd, u8 data)
 {
 	u32 val;

 	writel(data, i2cd->regs + I2C_MST_DATA);

 	val = I2C_MST_CNTL_CMD_WRITE | (1 << I2C_MST_CNTL_BURST_SIZE_SHIFT);
 	writel(val, i2cd->regs + I2C_MST_CNTL);

 	return gpu_i2c_check_status(i2cd);
 }

 static int gpu_i2c_master_xfer(struct i2c_adapter *adap,
 			       struct i2c_msg *msgs, int num)
 {
 	struct gpu_i2c_dev *i2cd = i2c_get_adapdata(adap);
 	int status, status2;
 	bool send_stop = true;
 	int i, j;

 	/*
 	 * The controller supports maximum 4 byte read due to known
 	 * limitation of sending STOP after every read.
 	 */
 	pm_runtime_get_sync(i2cd->dev);
 	for (i = 0; i < num; i++) {
 		if (msgs[i].flags & I2C_M_RD) {
 			/* program client address before starting read */
 			writel(msgs[i].addr, i2cd->regs + I2C_MST_ADDR);
 			/* gpu_i2c_read has implicit start */
 			status = gpu_i2c_read(i2cd, msgs[i].buf, msgs[i].len);
 			if (status < 0)
 				goto exit;
 		} else {
 			u8 addr = i2c_8bit_addr_from_msg(msgs + i);

 			status = gpu_i2c_start(i2cd);
 			if (status < 0) {
 				if (i == 0)
 					send_stop = false;
 				goto exit;
 			}

 			status = gpu_i2c_write(i2cd, addr);
 			if (status < 0)
 				goto exit;

 			for (j = 0; j < msgs[i].len; j++) {
 				status = gpu_i2c_write(i2cd, msgs[i].buf[j]);
 				if (status < 0)
 					goto exit;
 			}
 		}
 	}
 	send_stop = false;
 	status = gpu_i2c_stop(i2cd);
 	if (status < 0)
 		goto exit;

 	status = i;
 exit:
 	if (send_stop) {
 		status2 = gpu_i2c_stop(i2cd);
 		if (status2 < 0)
 			dev_err(i2cd->dev, "i2c stop failed %d\n", status2);
 	}
 	pm_runtime_mark_last_busy(i2cd->dev);
 	pm_runtime_put_autosuspend(i2cd->dev);
 	return status;
 }

 static const struct i2c_adapter_quirks gpu_i2c_quirks = {
 	.max_read_len = 4,
 	.max_comb_2nd_msg_len = 4,
 	.flags = I2C_AQ_COMB_WRITE_THEN_READ,
 };

 static u32 gpu_i2c_functionality(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }

 static const struct i2c_algorithm gpu_i2c_algorithm = {
 	.master_xfer	= gpu_i2c_master_xfer,
 	.functionality	= gpu_i2c_functionality,
 };

 /*
  * This driver is for Nvidia GPU cards with USB Type-C interface.
  * We want to identify the cards using vendor ID and class code only
  * to avoid dependency of adding product id for any new card which
  * requires this driver.
  * Currently there is no class code defined for UCSI device over PCI
  * so using UNKNOWN class for now and it will be updated when UCSI
  * over PCI gets a class code.
  * There is no other NVIDIA cards with UNKNOWN class code. Even if the
  * driver gets loaded for an undesired card then eventually i2c_read()
  * (initiated from UCSI i2c_client) will timeout or UCSI commands will
  * timeout.
  */
 #define PCI_CLASS_SERIAL_UNKNOWN	0x0c80
 static const struct pci_device_id gpu_i2c_ids[] = {
 	{ PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
 		PCI_CLASS_SERIAL_UNKNOWN << 8, 0xffffff00},
 	{ }
 };
 MODULE_DEVICE_TABLE(pci, gpu_i2c_ids);

 static const struct property_entry ccgx_props[] = {
 	/* Use FW built for NVIDIA (nv) only */
 	PROPERTY_ENTRY_U16("ccgx,firmware-build", ('n' << 8) | 'v'),
 	{ }
 };

 static int gpu_populate_client(struct gpu_i2c_dev *i2cd, int irq)
 {
 	i2cd->gpu_ccgx_ucsi = devm_kzalloc(i2cd->dev,
 					   sizeof(*i2cd->gpu_ccgx_ucsi),
 					   GFP_KERNEL);
 	if (!i2cd->gpu_ccgx_ucsi)
 		return -ENOMEM;

 	strlcpy(i2cd->gpu_ccgx_ucsi->type, "ccgx-ucsi",
 		sizeof(i2cd->gpu_ccgx_ucsi->type));
 	i2cd->gpu_ccgx_ucsi->addr = 0x8;
 	i2cd->gpu_ccgx_ucsi->irq = irq;
 	i2cd->gpu_ccgx_ucsi->properties = ccgx_props;
 	i2cd->ccgx_client = i2c_new_client_device(&i2cd->adapter, i2cd->gpu_ccgx_ucsi);
 	return PTR_ERR_OR_ZERO(i2cd->ccgx_client);
 }

 static int gpu_i2c_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	struct gpu_i2c_dev *i2cd;
 	int status;

 	i2cd = devm_kzalloc(&pdev->dev, sizeof(*i2cd), GFP_KERNEL);
 	if (!i2cd)
 		return -ENOMEM;

 	i2cd->dev = &pdev->dev;
 	dev_set_drvdata(&pdev->dev, i2cd);

 	status = pcim_enable_device(pdev);
 	if (status < 0) {
 		dev_err(&pdev->dev, "pcim_enable_device failed %d\n", status);
 		return status;
 	}

 	pci_set_master(pdev);

 	i2cd->regs = pcim_iomap(pdev, 0, 0);
 	if (!i2cd->regs) {
 		dev_err(&pdev->dev, "pcim_iomap failed\n");
 		return -ENOMEM;
 	}

 	status = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
 	if (status < 0) {
 		dev_err(&pdev->dev, "pci_alloc_irq_vectors err %d\n", status);
 		return status;
 	}

 	gpu_enable_i2c_bus(i2cd);

 	i2c_set_adapdata(&i2cd->adapter, i2cd);
 	i2cd->adapter.owner = THIS_MODULE;
 	strlcpy(i2cd->adapter.name, "NVIDIA GPU I2C adapter",
 		sizeof(i2cd->adapter.name));
 	i2cd->adapter.algo = &gpu_i2c_algorithm;
 	i2cd->adapter.quirks = &gpu_i2c_quirks;
 	i2cd->adapter.dev.parent = &pdev->dev;
 	status = i2c_add_adapter(&i2cd->adapter);
 	if (status < 0)
 		goto free_irq_vectors;

 	status = gpu_populate_client(i2cd, pdev->irq);
 	if (status < 0) {
 		dev_err(&pdev->dev, "gpu_populate_client failed %d\n", status);
 		goto del_adapter;
 	}

 	pm_runtime_set_autosuspend_delay(&pdev->dev, 3000);
 	pm_runtime_use_autosuspend(&pdev->dev);
 	pm_runtime_put_autosuspend(&pdev->dev);
 	pm_runtime_allow(&pdev->dev);

 	return 0;

 del_adapter:
 	i2c_del_adapter(&i2cd->adapter);
 free_irq_vectors:
 	pci_free_irq_vectors(pdev);
 	return status;
 }

 static void gpu_i2c_remove(struct pci_dev *pdev)
 {
 	struct gpu_i2c_dev *i2cd = dev_get_drvdata(&pdev->dev);

 	pm_runtime_get_noresume(i2cd->dev);
 	i2c_del_adapter(&i2cd->adapter);
 	pci_free_irq_vectors(pdev);
 }

 /*
  * We need gpu_i2c_suspend() even if it is stub, for runtime pm to work
  * correctly. Without it, lspci shows runtime pm status as "D0" for the card.
  * Documentation/power/pci.rst also insists for driver to provide this.
  */
 static __maybe_unused int gpu_i2c_suspend(struct device *dev)
 {
 	return 0;
 }

 static __maybe_unused int gpu_i2c_resume(struct device *dev)
 {
 	struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev);

 	gpu_enable_i2c_bus(i2cd);
 	/*
 	 * Runtime resume ccgx client so that it can see for any
 	 * connector change event. Old ccg firmware has known
 	 * issue of not triggering interrupt when a device is
 	 * connected to runtime resume the controller.
 	 */
 	pm_request_resume(&i2cd->ccgx_client->dev);
 	return 0;
 }

 static UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, gpu_i2c_suspend, gpu_i2c_resume,
 			    NULL);

 static struct pci_driver gpu_i2c_driver = {
 	.name		= "nvidia-gpu",
 	.id_table	= gpu_i2c_ids,
 	.probe		= gpu_i2c_probe,
 	.remove		= gpu_i2c_remove,
 	.driver		= {
 		.pm	= &gpu_i2c_driver_pm,
 	},
 };

 module_pci_driver(gpu_i2c_driver);

 MODULE_AUTHOR("Ajay Gupta <ajayg@nvidia.com>");
 MODULE_DESCRIPTION("Nvidia GPU I2C controller Driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Nvidia GPU I2C controller Driver
	*
	* Copyright (C) 2018 NVIDIA Corporation. All rights reserved.
	* Author: Ajay Gupta <ajayg@nvidia.com>
	*/
	#include <linux/delay.h>
	#include <linux/i2c.h>
	#include <linux/interrupt.h>
	#include <linux/iopoll.h>
	#include <linux/module.h>
	#include <linux/pci.h>
	#include <linux/platform_device.h>
	#include <linux/pm.h>
	#include <linux/pm_runtime.h>

	#include <asm/unaligned.h>

	/* I2C definitions */
	#define I2C_MST_CNTL 0x00
	#define I2C_MST_CNTL_GEN_START BIT(0)
	#define I2C_MST_CNTL_GEN_STOP BIT(1)
	#define I2C_MST_CNTL_CMD_READ (1 << 2)
	#define I2C_MST_CNTL_CMD_WRITE (2 << 2)
	#define I2C_MST_CNTL_BURST_SIZE_SHIFT 6
	#define I2C_MST_CNTL_GEN_NACK BIT(28)
	#define I2C_MST_CNTL_STATUS GENMASK(30, 29)
	#define I2C_MST_CNTL_STATUS_OKAY (0 << 29)
	#define I2C_MST_CNTL_STATUS_NO_ACK (1 << 29)
	#define I2C_MST_CNTL_STATUS_TIMEOUT (2 << 29)
	#define I2C_MST_CNTL_STATUS_BUS_BUSY (3 << 29)
	#define I2C_MST_CNTL_CYCLE_TRIGGER BIT(31)

	#define I2C_MST_ADDR 0x04

	#define I2C_MST_I2C0_TIMING 0x08
	#define I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ 0x10e
	#define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT 16
	#define I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX 255
	#define I2C_MST_I2C0_TIMING_TIMEOUT_CHECK BIT(24)

	#define I2C_MST_DATA 0x0c

	#define I2C_MST_HYBRID_PADCTL 0x20
	#define I2C_MST_HYBRID_PADCTL_MODE_I2C BIT(0)
	#define I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV BIT(14)
	#define I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV BIT(15)

	struct gpu_i2c_dev {
	struct device *dev;
	void __iomem *regs;
	struct i2c_adapter adapter;
	struct i2c_board_info *gpu_ccgx_ucsi;
	struct i2c_client *ccgx_client;
	};

	static void gpu_enable_i2c_bus(struct gpu_i2c_dev *i2cd)
	{
	u32 val;

	/* enable I2C */
	val = readl(i2cd->regs + I2C_MST_HYBRID_PADCTL);
	val \|= I2C_MST_HYBRID_PADCTL_MODE_I2C \|
	I2C_MST_HYBRID_PADCTL_I2C_SCL_INPUT_RCV \|
	I2C_MST_HYBRID_PADCTL_I2C_SDA_INPUT_RCV;
	writel(val, i2cd->regs + I2C_MST_HYBRID_PADCTL);

	/* enable 100KHZ mode */
	val = I2C_MST_I2C0_TIMING_SCL_PERIOD_100KHZ;
	val \|= (I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT_MAX
	<< I2C_MST_I2C0_TIMING_TIMEOUT_CLK_CNT);
	val \|= I2C_MST_I2C0_TIMING_TIMEOUT_CHECK;
	writel(val, i2cd->regs + I2C_MST_I2C0_TIMING);
	}

	static int gpu_i2c_check_status(struct gpu_i2c_dev *i2cd)
	{
	u32 val;
	int ret;

	ret = readl_poll_timeout(i2cd->regs + I2C_MST_CNTL, val,
	!(val & I2C_MST_CNTL_CYCLE_TRIGGER) \|\|
	(val & I2C_MST_CNTL_STATUS) != I2C_MST_CNTL_STATUS_BUS_BUSY,
	500, 1000 * USEC_PER_MSEC);

	if (ret) {
	dev_err(i2cd->dev, "i2c timeout error %x\n", val);
	return -ETIMEDOUT;
	}

	val = readl(i2cd->regs + I2C_MST_CNTL);
	switch (val & I2C_MST_CNTL_STATUS) {
	case I2C_MST_CNTL_STATUS_OKAY:
	return 0;
	case I2C_MST_CNTL_STATUS_NO_ACK:
	return -ENXIO;
	case I2C_MST_CNTL_STATUS_TIMEOUT:
	return -ETIMEDOUT;
	default:
	return 0;
	}
	}

	static int gpu_i2c_read(struct gpu_i2c_dev i2cd, u8 data, u16 len)
	{
	int status;
	u32 val;

	val = I2C_MST_CNTL_GEN_START \| I2C_MST_CNTL_CMD_READ \|
	(len << I2C_MST_CNTL_BURST_SIZE_SHIFT) \|
	I2C_MST_CNTL_CYCLE_TRIGGER \| I2C_MST_CNTL_GEN_NACK;
	writel(val, i2cd->regs + I2C_MST_CNTL);

	status = gpu_i2c_check_status(i2cd);
	if (status < 0)
	return status;

	val = readl(i2cd->regs + I2C_MST_DATA);
	switch (len) {
	case 1:
	data[0] = val;
	break;
	case 2:
	put_unaligned_be16(val, data);
	break;
	case 3:
	put_unaligned_be24(val, data);
	break;
	case 4:
	put_unaligned_be32(val, data);
	break;
	default:
	break;
	}
	return status;
	}

	static int gpu_i2c_start(struct gpu_i2c_dev *i2cd)
	{
	writel(I2C_MST_CNTL_GEN_START, i2cd->regs + I2C_MST_CNTL);
	return gpu_i2c_check_status(i2cd);
	}

	static int gpu_i2c_stop(struct gpu_i2c_dev *i2cd)
	{
	writel(I2C_MST_CNTL_GEN_STOP, i2cd->regs + I2C_MST_CNTL);
	return gpu_i2c_check_status(i2cd);
	}

	static int gpu_i2c_write(struct gpu_i2c_dev *i2cd, u8 data)
	{
	u32 val;

	writel(data, i2cd->regs + I2C_MST_DATA);

	val = I2C_MST_CNTL_CMD_WRITE \| (1 << I2C_MST_CNTL_BURST_SIZE_SHIFT);
	writel(val, i2cd->regs + I2C_MST_CNTL);

	return gpu_i2c_check_status(i2cd);
	}

	static int gpu_i2c_master_xfer(struct i2c_adapter *adap,
	struct i2c_msg *msgs, int num)
	{
	struct gpu_i2c_dev *i2cd = i2c_get_adapdata(adap);
	int status, status2;
	bool send_stop = true;
	int i, j;

	/*
	* The controller supports maximum 4 byte read due to known
	* limitation of sending STOP after every read.
	*/
	pm_runtime_get_sync(i2cd->dev);
	for (i = 0; i < num; i++) {
	if (msgs[i].flags & I2C_M_RD) {
	/* program client address before starting read */
	writel(msgs[i].addr, i2cd->regs + I2C_MST_ADDR);
	/* gpu_i2c_read has implicit start */
	status = gpu_i2c_read(i2cd, msgs[i].buf, msgs[i].len);
	if (status < 0)
	goto exit;
	} else {
	u8 addr = i2c_8bit_addr_from_msg(msgs + i);

	status = gpu_i2c_start(i2cd);
	if (status < 0) {
	if (i == 0)
	send_stop = false;
	goto exit;
	}

	status = gpu_i2c_write(i2cd, addr);
	if (status < 0)
	goto exit;

	for (j = 0; j < msgs[i].len; j++) {
	status = gpu_i2c_write(i2cd, msgs[i].buf[j]);
	if (status < 0)
	goto exit;
	}
	}
	}
	send_stop = false;
	status = gpu_i2c_stop(i2cd);
	if (status < 0)
	goto exit;

	status = i;
	exit:
	if (send_stop) {
	status2 = gpu_i2c_stop(i2cd);
	if (status2 < 0)
	dev_err(i2cd->dev, "i2c stop failed %d\n", status2);
	}
	pm_runtime_mark_last_busy(i2cd->dev);
	pm_runtime_put_autosuspend(i2cd->dev);
	return status;
	}

	static const struct i2c_adapter_quirks gpu_i2c_quirks = {
	.max_read_len = 4,
	.max_comb_2nd_msg_len = 4,
	.flags = I2C_AQ_COMB_WRITE_THEN_READ,
	};

	static u32 gpu_i2c_functionality(struct i2c_adapter *adap)
	{
	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL;
	}

	static const struct i2c_algorithm gpu_i2c_algorithm = {
	.master_xfer = gpu_i2c_master_xfer,
	.functionality = gpu_i2c_functionality,
	};

	/*
	* This driver is for Nvidia GPU cards with USB Type-C interface.
	* We want to identify the cards using vendor ID and class code only
	* to avoid dependency of adding product id for any new card which
	* requires this driver.
	* Currently there is no class code defined for UCSI device over PCI
	* so using UNKNOWN class for now and it will be updated when UCSI
	* over PCI gets a class code.
	* There is no other NVIDIA cards with UNKNOWN class code. Even if the
	* driver gets loaded for an undesired card then eventually i2c_read()
	* (initiated from UCSI i2c_client) will timeout or UCSI commands will
	* timeout.
	*/
	#define PCI_CLASS_SERIAL_UNKNOWN 0x0c80
	static const struct pci_device_id gpu_i2c_ids[] = {
	{ PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
	PCI_CLASS_SERIAL_UNKNOWN << 8, 0xffffff00},
	{ }
	};
	MODULE_DEVICE_TABLE(pci, gpu_i2c_ids);

	static const struct property_entry ccgx_props[] = {
	/* Use FW built for NVIDIA (nv) only */
	PROPERTY_ENTRY_U16("ccgx,firmware-build", ('n' << 8) \| 'v'),
	{ }
	};

	static int gpu_populate_client(struct gpu_i2c_dev *i2cd, int irq)
	{
	i2cd->gpu_ccgx_ucsi = devm_kzalloc(i2cd->dev,
	sizeof(*i2cd->gpu_ccgx_ucsi),
	GFP_KERNEL);
	if (!i2cd->gpu_ccgx_ucsi)
	return -ENOMEM;

	strlcpy(i2cd->gpu_ccgx_ucsi->type, "ccgx-ucsi",
	sizeof(i2cd->gpu_ccgx_ucsi->type));
	i2cd->gpu_ccgx_ucsi->addr = 0x8;
	i2cd->gpu_ccgx_ucsi->irq = irq;
	i2cd->gpu_ccgx_ucsi->properties = ccgx_props;
	i2cd->ccgx_client = i2c_new_client_device(&i2cd->adapter, i2cd->gpu_ccgx_ucsi);
	return PTR_ERR_OR_ZERO(i2cd->ccgx_client);
	}

	static int gpu_i2c_probe(struct pci_dev pdev, const struct pci_device_id id)
	{
	struct gpu_i2c_dev *i2cd;
	int status;

	i2cd = devm_kzalloc(&pdev->dev, sizeof(*i2cd), GFP_KERNEL);
	if (!i2cd)
	return -ENOMEM;

	i2cd->dev = &pdev->dev;
	dev_set_drvdata(&pdev->dev, i2cd);

	status = pcim_enable_device(pdev);
	if (status < 0) {
	dev_err(&pdev->dev, "pcim_enable_device failed %d\n", status);
	return status;
	}

	pci_set_master(pdev);

	i2cd->regs = pcim_iomap(pdev, 0, 0);
	if (!i2cd->regs) {
	dev_err(&pdev->dev, "pcim_iomap failed\n");
	return -ENOMEM;
	}

	status = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
	if (status < 0) {
	dev_err(&pdev->dev, "pci_alloc_irq_vectors err %d\n", status);
	return status;
	}

	gpu_enable_i2c_bus(i2cd);

	i2c_set_adapdata(&i2cd->adapter, i2cd);
	i2cd->adapter.owner = THIS_MODULE;
	strlcpy(i2cd->adapter.name, "NVIDIA GPU I2C adapter",
	sizeof(i2cd->adapter.name));
	i2cd->adapter.algo = &gpu_i2c_algorithm;
	i2cd->adapter.quirks = &gpu_i2c_quirks;
	i2cd->adapter.dev.parent = &pdev->dev;
	status = i2c_add_adapter(&i2cd->adapter);
	if (status < 0)
	goto free_irq_vectors;

	status = gpu_populate_client(i2cd, pdev->irq);
	if (status < 0) {
	dev_err(&pdev->dev, "gpu_populate_client failed %d\n", status);
	goto del_adapter;
	}

	pm_runtime_set_autosuspend_delay(&pdev->dev, 3000);
	pm_runtime_use_autosuspend(&pdev->dev);
	pm_runtime_put_autosuspend(&pdev->dev);
	pm_runtime_allow(&pdev->dev);

	return 0;

	del_adapter:
	i2c_del_adapter(&i2cd->adapter);
	free_irq_vectors:
	pci_free_irq_vectors(pdev);
	return status;
	}

	static void gpu_i2c_remove(struct pci_dev *pdev)
	{
	struct gpu_i2c_dev *i2cd = dev_get_drvdata(&pdev->dev);

	pm_runtime_get_noresume(i2cd->dev);
	i2c_del_adapter(&i2cd->adapter);
	pci_free_irq_vectors(pdev);
	}

	/*
	* We need gpu_i2c_suspend() even if it is stub, for runtime pm to work
	* correctly. Without it, lspci shows runtime pm status as "D0" for the card.
	* Documentation/power/pci.rst also insists for driver to provide this.
	*/
	static __maybe_unused int gpu_i2c_suspend(struct device *dev)
	{
	return 0;
	}

	static __maybe_unused int gpu_i2c_resume(struct device *dev)
	{
	struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev);

	gpu_enable_i2c_bus(i2cd);
	/*
	* Runtime resume ccgx client so that it can see for any
	* connector change event. Old ccg firmware has known
	* issue of not triggering interrupt when a device is
	* connected to runtime resume the controller.
	*/
	pm_request_resume(&i2cd->ccgx_client->dev);
	return 0;
	}

	static UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, gpu_i2c_suspend, gpu_i2c_resume,
	NULL);

	static struct pci_driver gpu_i2c_driver = {
	.name = "nvidia-gpu",
	.id_table = gpu_i2c_ids,
	.probe = gpu_i2c_probe,
	.remove = gpu_i2c_remove,
	.driver = {
	.pm = &gpu_i2c_driver_pm,
	},
	};

	module_pci_driver(gpu_i2c_driver);

	MODULE_AUTHOR("Ajay Gupta <ajayg@nvidia.com>");
	MODULE_DESCRIPTION("Nvidia GPU I2C controller Driver");
	MODULE_LICENSE("GPL v2");