drivers/i2c/busses/i2c-tegra-bpmp.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * drivers/i2c/busses/i2c-tegra-bpmp.c
  *
  * Copyright (c) 2016 NVIDIA Corporation.  All rights reserved.
  *
  * Author: Shardar Shariff Md <smohammed@nvidia.com>
  */

 #include <linux/err.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>

 #include <soc/tegra/bpmp-abi.h>
 #include <soc/tegra/bpmp.h>

 /*
  * Serialized I2C message header size is 6 bytes and includes address, flags
  * and length
  */
 #define SERIALI2C_HDR_SIZE 6

 struct tegra_bpmp_i2c {
 	struct i2c_adapter adapter;
 	struct device *dev;

 	struct tegra_bpmp *bpmp;
 	unsigned int bus;
 };

 /*
  * Linux flags are translated to BPMP defined I2C flags that are used in BPMP
  * firmware I2C driver to avoid any issues in future if Linux I2C flags are
  * changed.
  */
 static int tegra_bpmp_xlate_flags(u16 flags, u16 *out)
 {
 	if (flags & I2C_M_TEN) {
 		*out |= SERIALI2C_TEN;
 		flags &= ~I2C_M_TEN;
 	}

 	if (flags & I2C_M_RD) {
 		*out |= SERIALI2C_RD;
 		flags &= ~I2C_M_RD;
 	}

 	if (flags & I2C_M_STOP) {
 		*out |= SERIALI2C_STOP;
 		flags &= ~I2C_M_STOP;
 	}

 	if (flags & I2C_M_NOSTART) {
 		*out |= SERIALI2C_NOSTART;
 		flags &= ~I2C_M_NOSTART;
 	}

 	if (flags & I2C_M_REV_DIR_ADDR) {
 		*out |= SERIALI2C_REV_DIR_ADDR;
 		flags &= ~I2C_M_REV_DIR_ADDR;
 	}

 	if (flags & I2C_M_IGNORE_NAK) {
 		*out |= SERIALI2C_IGNORE_NAK;
 		flags &= ~I2C_M_IGNORE_NAK;
 	}

 	if (flags & I2C_M_NO_RD_ACK) {
 		*out |= SERIALI2C_NO_RD_ACK;
 		flags &= ~I2C_M_NO_RD_ACK;
 	}

 	if (flags & I2C_M_RECV_LEN) {
 		*out |= SERIALI2C_RECV_LEN;
 		flags &= ~I2C_M_RECV_LEN;
 	}

 	return 0;
 }

 /**
  * The serialized I2C format is simply the following:
  * [addr little-endian][flags little-endian][len little-endian][data if write]
  * [addr little-endian][flags little-endian][len little-endian][data if write]
  *  ...
  *
  * The flags are translated from Linux kernel representation to seriali2c
  * representation. Any undefined flag being set causes an error.
  *
  * The data is there only for writes. Reads have the data transferred in the
  * other direction, and thus data is not present.
  *
  * See deserialize_i2c documentation for the data format in the other direction.
  */
 static int tegra_bpmp_serialize_i2c_msg(struct tegra_bpmp_i2c *i2c,
 					struct mrq_i2c_request *request,
 					struct i2c_msg *msgs,
 					unsigned int num)
 {
 	char *buf = request->xfer.data_buf;
 	unsigned int i, j, pos = 0;
 	int err;

 	for (i = 0; i < num; i++) {
 		struct i2c_msg *msg = &msgs[i];
 		u16 flags = 0;

 		err = tegra_bpmp_xlate_flags(msg->flags, &flags);
 		if (err < 0)
 			return err;

 		buf[pos++] = msg->addr & 0xff;
 		buf[pos++] = (msg->addr & 0xff00) >> 8;
 		buf[pos++] = flags & 0xff;
 		buf[pos++] = (flags & 0xff00) >> 8;
 		buf[pos++] = msg->len & 0xff;
 		buf[pos++] = (msg->len & 0xff00) >> 8;

 		if ((flags & SERIALI2C_RD) == 0) {
 			for (j = 0; j < msg->len; j++)
 				buf[pos++] = msg->buf[j];
 		}
 	}

 	request->xfer.data_size = pos;

 	return 0;
 }

 /**
  * The data in the BPMP -> CPU direction is composed of sequential blocks for
  * those messages that have I2C_M_RD. So, for example, if you have:
  *
  * - !I2C_M_RD, len == 5, data == a0 01 02 03 04
  * - !I2C_M_RD, len == 1, data == a0
  * - I2C_M_RD, len == 2, data == [uninitialized buffer 1]
  * - !I2C_M_RD, len == 1, data == a2
  * - I2C_M_RD, len == 2, data == [uninitialized buffer 2]
  *
  * ...then the data in the BPMP -> CPU direction would be 4 bytes total, and
  * would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes
  * that will go to uninitialized buffer 2.
  */
 static int tegra_bpmp_i2c_deserialize(struct tegra_bpmp_i2c *i2c,
 				      struct mrq_i2c_response *response,
 				      struct i2c_msg *msgs,
 				      unsigned int num)
 {
 	size_t size = response->xfer.data_size, len = 0, pos = 0;
 	char *buf = response->xfer.data_buf;
 	unsigned int i;

 	for (i = 0; i < num; i++)
 		if (msgs[i].flags & I2C_M_RD)
 			len += msgs[i].len;

 	if (len != size)
 		return -EINVAL;

 	for (i = 0; i < num; i++) {
 		if (msgs[i].flags & I2C_M_RD) {
 			memcpy(msgs[i].buf, buf + pos, msgs[i].len);
 			pos += msgs[i].len;
 		}
 	}

 	return 0;
 }

 static int tegra_bpmp_i2c_msg_len_check(struct i2c_msg *msgs, unsigned int num)
 {
 	size_t tx_len = 0, rx_len = 0;
 	unsigned int i;

 	for (i = 0; i < num; i++)
 		if (!(msgs[i].flags & I2C_M_RD))
 			tx_len += SERIALI2C_HDR_SIZE + msgs[i].len;

 	if (tx_len > TEGRA_I2C_IPC_MAX_IN_BUF_SIZE)
 		return -EINVAL;

 	for (i = 0; i < num; i++)
 		if ((msgs[i].flags & I2C_M_RD))
 			rx_len += msgs[i].len;

 	if (rx_len > TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE)
 		return -EINVAL;

 	return 0;
 }

 static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c,
 				   struct mrq_i2c_request *request,
 				   struct mrq_i2c_response *response,
 				   bool atomic)
 {
 	struct tegra_bpmp_message msg;
 	int err;

 	request->cmd = CMD_I2C_XFER;
 	request->xfer.bus_id = i2c->bus;

 	memset(&msg, 0, sizeof(msg));
 	msg.mrq = MRQ_I2C;
 	msg.tx.data = request;
 	msg.tx.size = sizeof(*request);
 	msg.rx.data = response;
 	msg.rx.size = sizeof(*response);

 	if (atomic)
 		err = tegra_bpmp_transfer_atomic(i2c->bpmp, &msg);
 	else
 		err = tegra_bpmp_transfer(i2c->bpmp, &msg);

 	return err;
 }

 static int tegra_bpmp_i2c_xfer_common(struct i2c_adapter *adapter,
 				      struct i2c_msg *msgs, int num,
 				      bool atomic)
 {
 	struct tegra_bpmp_i2c *i2c = i2c_get_adapdata(adapter);
 	struct mrq_i2c_response response;
 	struct mrq_i2c_request request;
 	int err;

 	err = tegra_bpmp_i2c_msg_len_check(msgs, num);
 	if (err < 0) {
 		dev_err(i2c->dev, "unsupported message length\n");
 		return err;
 	}

 	memset(&request, 0, sizeof(request));
 	memset(&response, 0, sizeof(response));

 	err = tegra_bpmp_serialize_i2c_msg(i2c, &request, msgs, num);
 	if (err < 0) {
 		dev_err(i2c->dev, "failed to serialize message: %d\n", err);
 		return err;
 	}

 	err = tegra_bpmp_i2c_msg_xfer(i2c, &request, &response, atomic);
 	if (err < 0) {
 		dev_err(i2c->dev, "failed to transfer message: %d\n", err);
 		return err;
 	}

 	err = tegra_bpmp_i2c_deserialize(i2c, &response, msgs, num);
 	if (err < 0) {
 		dev_err(i2c->dev, "failed to deserialize message: %d\n", err);
 		return err;
 	}

 	return num;
 }

 static int tegra_bpmp_i2c_xfer(struct i2c_adapter *adapter,
 			       struct i2c_msg *msgs, int num)
 {
 	return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, false);
 }

 static int tegra_bpmp_i2c_xfer_atomic(struct i2c_adapter *adapter,
 				      struct i2c_msg *msgs, int num)
 {
 	return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, true);
 }

 static u32 tegra_bpmp_i2c_func(struct i2c_adapter *adapter)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
 	       I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART;
 }

 static const struct i2c_algorithm tegra_bpmp_i2c_algo = {
 	.master_xfer = tegra_bpmp_i2c_xfer,
 	.master_xfer_atomic = tegra_bpmp_i2c_xfer_atomic,
 	.functionality = tegra_bpmp_i2c_func,
 };

 static int tegra_bpmp_i2c_probe(struct platform_device *pdev)
 {
 	struct tegra_bpmp_i2c *i2c;
 	u32 value;
 	int err;

 	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
 	if (!i2c)
 		return -ENOMEM;

 	i2c->dev = &pdev->dev;

 	i2c->bpmp = dev_get_drvdata(pdev->dev.parent);
 	if (!i2c->bpmp)
 		return -ENODEV;

 	err = of_property_read_u32(pdev->dev.of_node, "nvidia,bpmp-bus-id",
 				   &value);
 	if (err < 0)
 		return err;

 	i2c->bus = value;

 	i2c_set_adapdata(&i2c->adapter, i2c);
 	i2c->adapter.owner = THIS_MODULE;
 	strlcpy(i2c->adapter.name, "Tegra BPMP I2C adapter",
 		sizeof(i2c->adapter.name));
 	i2c->adapter.algo = &tegra_bpmp_i2c_algo;
 	i2c->adapter.dev.parent = &pdev->dev;
 	i2c->adapter.dev.of_node = pdev->dev.of_node;

 	platform_set_drvdata(pdev, i2c);

 	return i2c_add_adapter(&i2c->adapter);
 }

 static int tegra_bpmp_i2c_remove(struct platform_device *pdev)
 {
 	struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev);

 	i2c_del_adapter(&i2c->adapter);

 	return 0;
 }

 static const struct of_device_id tegra_bpmp_i2c_of_match[] = {
 	{ .compatible = "nvidia,tegra186-bpmp-i2c", },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match);

 static struct platform_driver tegra_bpmp_i2c_driver = {
 	.driver = {
 		.name = "tegra-bpmp-i2c",
 		.of_match_table = tegra_bpmp_i2c_of_match,
 	},
 	.probe = tegra_bpmp_i2c_probe,
 	.remove = tegra_bpmp_i2c_remove,
 };
 module_platform_driver(tegra_bpmp_i2c_driver);

 MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver");
 MODULE_AUTHOR("Shardar Shariff Md <smohammed@nvidia.com>");
 MODULE_AUTHOR("Juha-Matti Tilli");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* drivers/i2c/busses/i2c-tegra-bpmp.c
	*
	* Copyright (c) 2016 NVIDIA Corporation. All rights reserved.
	*
	* Author: Shardar Shariff Md <smohammed@nvidia.com>
	*/

	#include <linux/err.h>
	#include <linux/i2c.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of_device.h>
	#include <linux/platform_device.h>
	#include <linux/pm_runtime.h>

	#include <soc/tegra/bpmp-abi.h>
	#include <soc/tegra/bpmp.h>

	/*
	* Serialized I2C message header size is 6 bytes and includes address, flags
	* and length
	*/
	#define SERIALI2C_HDR_SIZE 6

	struct tegra_bpmp_i2c {
	struct i2c_adapter adapter;
	struct device *dev;

	struct tegra_bpmp *bpmp;
	unsigned int bus;
	};

	/*
	* Linux flags are translated to BPMP defined I2C flags that are used in BPMP
	* firmware I2C driver to avoid any issues in future if Linux I2C flags are
	* changed.
	*/
	static int tegra_bpmp_xlate_flags(u16 flags, u16 *out)
	{
	if (flags & I2C_M_TEN) {
	*out \|= SERIALI2C_TEN;
	flags &= ~I2C_M_TEN;
	}

	if (flags & I2C_M_RD) {
	*out \|= SERIALI2C_RD;
	flags &= ~I2C_M_RD;
	}

	if (flags & I2C_M_STOP) {
	*out \|= SERIALI2C_STOP;
	flags &= ~I2C_M_STOP;
	}

	if (flags & I2C_M_NOSTART) {
	*out \|= SERIALI2C_NOSTART;
	flags &= ~I2C_M_NOSTART;
	}

	if (flags & I2C_M_REV_DIR_ADDR) {
	*out \|= SERIALI2C_REV_DIR_ADDR;
	flags &= ~I2C_M_REV_DIR_ADDR;
	}

	if (flags & I2C_M_IGNORE_NAK) {
	*out \|= SERIALI2C_IGNORE_NAK;
	flags &= ~I2C_M_IGNORE_NAK;
	}

	if (flags & I2C_M_NO_RD_ACK) {
	*out \|= SERIALI2C_NO_RD_ACK;
	flags &= ~I2C_M_NO_RD_ACK;
	}

	if (flags & I2C_M_RECV_LEN) {
	*out \|= SERIALI2C_RECV_LEN;
	flags &= ~I2C_M_RECV_LEN;
	}

	return 0;
	}

	/**
	* The serialized I2C format is simply the following:
	* [addr little-endian][flags little-endian][len little-endian][data if write]
	* [addr little-endian][flags little-endian][len little-endian][data if write]
	* ...
	*
	* The flags are translated from Linux kernel representation to seriali2c
	* representation. Any undefined flag being set causes an error.
	*
	* The data is there only for writes. Reads have the data transferred in the
	* other direction, and thus data is not present.
	*
	* See deserialize_i2c documentation for the data format in the other direction.
	*/
	static int tegra_bpmp_serialize_i2c_msg(struct tegra_bpmp_i2c *i2c,
	struct mrq_i2c_request *request,
	struct i2c_msg *msgs,
	unsigned int num)
	{
	char *buf = request->xfer.data_buf;
	unsigned int i, j, pos = 0;
	int err;

	for (i = 0; i < num; i++) {
	struct i2c_msg *msg = &msgs[i];
	u16 flags = 0;

	err = tegra_bpmp_xlate_flags(msg->flags, &flags);
	if (err < 0)
	return err;

	buf[pos++] = msg->addr & 0xff;
	buf[pos++] = (msg->addr & 0xff00) >> 8;
	buf[pos++] = flags & 0xff;
	buf[pos++] = (flags & 0xff00) >> 8;
	buf[pos++] = msg->len & 0xff;
	buf[pos++] = (msg->len & 0xff00) >> 8;

	if ((flags & SERIALI2C_RD) == 0) {
	for (j = 0; j < msg->len; j++)
	buf[pos++] = msg->buf[j];
	}
	}

	request->xfer.data_size = pos;

	return 0;
	}

	/**
	* The data in the BPMP -> CPU direction is composed of sequential blocks for
	* those messages that have I2C_M_RD. So, for example, if you have:
	*
	* - !I2C_M_RD, len == 5, data == a0 01 02 03 04
	* - !I2C_M_RD, len == 1, data == a0
	* - I2C_M_RD, len == 2, data == [uninitialized buffer 1]
	* - !I2C_M_RD, len == 1, data == a2
	* - I2C_M_RD, len == 2, data == [uninitialized buffer 2]
	*
	* ...then the data in the BPMP -> CPU direction would be 4 bytes total, and
	* would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes
	* that will go to uninitialized buffer 2.
	*/
	static int tegra_bpmp_i2c_deserialize(struct tegra_bpmp_i2c *i2c,
	struct mrq_i2c_response *response,
	struct i2c_msg *msgs,
	unsigned int num)
	{
	size_t size = response->xfer.data_size, len = 0, pos = 0;
	char *buf = response->xfer.data_buf;
	unsigned int i;

	for (i = 0; i < num; i++)
	if (msgs[i].flags & I2C_M_RD)
	len += msgs[i].len;

	if (len != size)
	return -EINVAL;

	for (i = 0; i < num; i++) {
	if (msgs[i].flags & I2C_M_RD) {
	memcpy(msgs[i].buf, buf + pos, msgs[i].len);
	pos += msgs[i].len;
	}
	}

	return 0;
	}

	static int tegra_bpmp_i2c_msg_len_check(struct i2c_msg *msgs, unsigned int num)
	{
	size_t tx_len = 0, rx_len = 0;
	unsigned int i;

	for (i = 0; i < num; i++)
	if (!(msgs[i].flags & I2C_M_RD))
	tx_len += SERIALI2C_HDR_SIZE + msgs[i].len;

	if (tx_len > TEGRA_I2C_IPC_MAX_IN_BUF_SIZE)
	return -EINVAL;

	for (i = 0; i < num; i++)
	if ((msgs[i].flags & I2C_M_RD))
	rx_len += msgs[i].len;

	if (rx_len > TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE)
	return -EINVAL;

	return 0;
	}

	static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c,
	struct mrq_i2c_request *request,
	struct mrq_i2c_response *response,
	bool atomic)
	{
	struct tegra_bpmp_message msg;
	int err;

	request->cmd = CMD_I2C_XFER;
	request->xfer.bus_id = i2c->bus;

	memset(&msg, 0, sizeof(msg));
	msg.mrq = MRQ_I2C;
	msg.tx.data = request;
	msg.tx.size = sizeof(*request);
	msg.rx.data = response;
	msg.rx.size = sizeof(*response);

	if (atomic)
	err = tegra_bpmp_transfer_atomic(i2c->bpmp, &msg);
	else
	err = tegra_bpmp_transfer(i2c->bpmp, &msg);

	return err;
	}

	static int tegra_bpmp_i2c_xfer_common(struct i2c_adapter *adapter,
	struct i2c_msg *msgs, int num,
	bool atomic)
	{
	struct tegra_bpmp_i2c *i2c = i2c_get_adapdata(adapter);
	struct mrq_i2c_response response;
	struct mrq_i2c_request request;
	int err;

	err = tegra_bpmp_i2c_msg_len_check(msgs, num);
	if (err < 0) {
	dev_err(i2c->dev, "unsupported message length\n");
	return err;
	}

	memset(&request, 0, sizeof(request));
	memset(&response, 0, sizeof(response));

	err = tegra_bpmp_serialize_i2c_msg(i2c, &request, msgs, num);
	if (err < 0) {
	dev_err(i2c->dev, "failed to serialize message: %d\n", err);
	return err;
	}

	err = tegra_bpmp_i2c_msg_xfer(i2c, &request, &response, atomic);
	if (err < 0) {
	dev_err(i2c->dev, "failed to transfer message: %d\n", err);
	return err;
	}

	err = tegra_bpmp_i2c_deserialize(i2c, &response, msgs, num);
	if (err < 0) {
	dev_err(i2c->dev, "failed to deserialize message: %d\n", err);
	return err;
	}

	return num;
	}

	static int tegra_bpmp_i2c_xfer(struct i2c_adapter *adapter,
	struct i2c_msg *msgs, int num)
	{
	return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, false);
	}

	static int tegra_bpmp_i2c_xfer_atomic(struct i2c_adapter *adapter,
	struct i2c_msg *msgs, int num)
	{
	return tegra_bpmp_i2c_xfer_common(adapter, msgs, num, true);
	}

	static u32 tegra_bpmp_i2c_func(struct i2c_adapter *adapter)
	{
	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL \| I2C_FUNC_10BIT_ADDR \|
	I2C_FUNC_PROTOCOL_MANGLING \| I2C_FUNC_NOSTART;
	}

	static const struct i2c_algorithm tegra_bpmp_i2c_algo = {
	.master_xfer = tegra_bpmp_i2c_xfer,
	.master_xfer_atomic = tegra_bpmp_i2c_xfer_atomic,
	.functionality = tegra_bpmp_i2c_func,
	};

	static int tegra_bpmp_i2c_probe(struct platform_device *pdev)
	{
	struct tegra_bpmp_i2c *i2c;
	u32 value;
	int err;

	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
	if (!i2c)
	return -ENOMEM;

	i2c->dev = &pdev->dev;

	i2c->bpmp = dev_get_drvdata(pdev->dev.parent);
	if (!i2c->bpmp)
	return -ENODEV;

	err = of_property_read_u32(pdev->dev.of_node, "nvidia,bpmp-bus-id",
	&value);
	if (err < 0)
	return err;

	i2c->bus = value;

	i2c_set_adapdata(&i2c->adapter, i2c);
	i2c->adapter.owner = THIS_MODULE;
	strlcpy(i2c->adapter.name, "Tegra BPMP I2C adapter",
	sizeof(i2c->adapter.name));
	i2c->adapter.algo = &tegra_bpmp_i2c_algo;
	i2c->adapter.dev.parent = &pdev->dev;
	i2c->adapter.dev.of_node = pdev->dev.of_node;

	platform_set_drvdata(pdev, i2c);

	return i2c_add_adapter(&i2c->adapter);
	}

	static int tegra_bpmp_i2c_remove(struct platform_device *pdev)
	{
	struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev);

	i2c_del_adapter(&i2c->adapter);

	return 0;
	}

	static const struct of_device_id tegra_bpmp_i2c_of_match[] = {
	{ .compatible = "nvidia,tegra186-bpmp-i2c", },
	{ }
	};
	MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match);

	static struct platform_driver tegra_bpmp_i2c_driver = {
	.driver = {
	.name = "tegra-bpmp-i2c",
	.of_match_table = tegra_bpmp_i2c_of_match,
	},
	.probe = tegra_bpmp_i2c_probe,
	.remove = tegra_bpmp_i2c_remove,
	};
	module_platform_driver(tegra_bpmp_i2c_driver);

	MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus controller driver");
	MODULE_AUTHOR("Shardar Shariff Md <smohammed@nvidia.com>");
	MODULE_AUTHOR("Juha-Matti Tilli");
	MODULE_LICENSE("GPL v2");