drivers/char/tpm/st33zp24/i2c.c - linux - Git at Google

 /*
  * STMicroelectronics TPM I2C Linux driver for TPM ST33ZP24
  * Copyright (C) 2009 - 2015 STMicroelectronics
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */

 #include <linux/module.h>
 #include <linux/i2c.h>
 #include <linux/gpio.h>
 #include <linux/of_irq.h>
 #include <linux/of_gpio.h>
 #include <linux/tpm.h>
 #include <linux/platform_data/st33zp24.h>

 #include "st33zp24.h"

 #define TPM_DUMMY_BYTE			0xAA

 struct st33zp24_i2c_phy {
 	struct i2c_client *client;
 	u8 buf[TPM_BUFSIZE + 1];
 	int io_lpcpd;
 };

 /*
  * write8_reg
  * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
  * @param: tpm_register, the tpm tis register where the data should be written
  * @param: tpm_data, the tpm_data to write inside the tpm_register
  * @param: tpm_size, The length of the data
  * @return: Returns negative errno, or else the number of bytes written.
  */
 static int write8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
 {
 	struct st33zp24_i2c_phy *phy = phy_id;

 	phy->buf[0] = tpm_register;
 	memcpy(phy->buf + 1, tpm_data, tpm_size);
 	return i2c_master_send(phy->client, phy->buf, tpm_size + 1);
 } /* write8_reg() */

 /*
  * read8_reg
  * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
  * @param: tpm_register, the tpm tis register where the data should be read
  * @param: tpm_data, the TPM response
  * @param: tpm_size, tpm TPM response size to read.
  * @return: number of byte read successfully: should be one if success.
  */
 static int read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
 {
 	struct st33zp24_i2c_phy *phy = phy_id;
 	u8 status = 0;
 	u8 data;

 	data = TPM_DUMMY_BYTE;
 	status = write8_reg(phy, tpm_register, &data, 1);
 	if (status == 2)
 		status = i2c_master_recv(phy->client, tpm_data, tpm_size);
 	return status;
 } /* read8_reg() */

 /*
  * st33zp24_i2c_send
  * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
  * @param: phy_id, the phy description
  * @param: tpm_register, the tpm tis register where the data should be written
  * @param: tpm_data, the tpm_data to write inside the tpm_register
  * @param: tpm_size, the length of the data
  * @return: number of byte written successfully: should be one if success.
  */
 static int st33zp24_i2c_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
 			     int tpm_size)
 {
 	return write8_reg(phy_id, tpm_register | TPM_WRITE_DIRECTION, tpm_data,
 			  tpm_size);
 }

 /*
  * st33zp24_i2c_recv
  * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
  * @param: phy_id, the phy description
  * @param: tpm_register, the tpm tis register where the data should be read
  * @param: tpm_data, the TPM response
  * @param: tpm_size, tpm TPM response size to read.
  * @return: number of byte read successfully: should be one if success.
  */
 static int st33zp24_i2c_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
 			     int tpm_size)
 {
 	return read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
 }

 static const struct st33zp24_phy_ops i2c_phy_ops = {
 	.send = st33zp24_i2c_send,
 	.recv = st33zp24_i2c_recv,
 };

 #ifdef CONFIG_OF
 static int st33zp24_i2c_of_request_resources(struct st33zp24_i2c_phy *phy)
 {
 	struct device_node *pp;
 	struct i2c_client *client = phy->client;
 	int gpio;
 	int ret;

 	pp = client->dev.of_node;
 	if (!pp) {
 		dev_err(&client->dev, "No platform data\n");
 		return -ENODEV;
 	}

 	/* Get GPIO from device tree */
 	gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0);
 	if (gpio < 0) {
 		dev_err(&client->dev,
 			"Failed to retrieve lpcpd-gpios from dts.\n");
 		phy->io_lpcpd = -1;
 		/*
 		 * lpcpd pin is not specified. This is not an issue as
 		 * power management can be also managed by TPM specific
 		 * commands. So leave with a success status code.
 		 */
 		return 0;
 	}
 	/* GPIO request and configuration */
 	ret = devm_gpio_request_one(&client->dev, gpio,
 			GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD");
 	if (ret) {
 		dev_err(&client->dev, "Failed to request lpcpd pin\n");
 		return -ENODEV;
 	}
 	phy->io_lpcpd = gpio;

 	return 0;
 }
 #else
 static int st33zp24_i2c_of_request_resources(struct st33zp24_i2c_phy *phy)
 {
 	return -ENODEV;
 }
 #endif

 static int st33zp24_i2c_request_resources(struct i2c_client *client,
 					  struct st33zp24_i2c_phy *phy)
 {
 	struct st33zp24_platform_data *pdata;
 	int ret;

 	pdata = client->dev.platform_data;
 	if (!pdata) {
 		dev_err(&client->dev, "No platform data\n");
 		return -ENODEV;
 	}

 	/* store for late use */
 	phy->io_lpcpd = pdata->io_lpcpd;

 	if (gpio_is_valid(pdata->io_lpcpd)) {
 		ret = devm_gpio_request_one(&client->dev,
 				pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH,
 				"TPM IO_LPCPD");
 		if (ret) {
 			dev_err(&client->dev, "Failed to request lpcpd pin\n");
 			return ret;
 		}
 	}

 	return 0;
 }

 /*
  * st33zp24_i2c_probe initialize the TPM device
  * @param: client, the i2c_client drescription (TPM I2C description).
  * @param: id, the i2c_device_id struct.
  * @return: 0 in case of success.
  *	 -1 in other case.
  */
 static int st33zp24_i2c_probe(struct i2c_client *client,
 			      const struct i2c_device_id *id)
 {
 	int ret;
 	struct st33zp24_platform_data *pdata;
 	struct st33zp24_i2c_phy *phy;

 	if (!client) {
 		pr_info("%s: i2c client is NULL. Device not accessible.\n",
 			__func__);
 		return -ENODEV;
 	}

 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 		dev_info(&client->dev, "client not i2c capable\n");
 		return -ENODEV;
 	}

 	phy = devm_kzalloc(&client->dev, sizeof(struct st33zp24_i2c_phy),
 			   GFP_KERNEL);
 	if (!phy)
 		return -ENOMEM;

 	phy->client = client;
 	pdata = client->dev.platform_data;
 	if (!pdata && client->dev.of_node) {
 		ret = st33zp24_i2c_of_request_resources(phy);
 		if (ret)
 			return ret;
 	} else if (pdata) {
 		ret = st33zp24_i2c_request_resources(client, phy);
 		if (ret)
 			return ret;
 	}

 	return st33zp24_probe(phy, &i2c_phy_ops, &client->dev, client->irq,
 			      phy->io_lpcpd);
 }

 /*
  * st33zp24_i2c_remove remove the TPM device
  * @param: client, the i2c_client description (TPM I2C description).
  * @return: 0 in case of success.
  */
 static int st33zp24_i2c_remove(struct i2c_client *client)
 {
 	struct tpm_chip *chip = i2c_get_clientdata(client);

 	return st33zp24_remove(chip);
 }

 static const struct i2c_device_id st33zp24_i2c_id[] = {
 	{TPM_ST33_I2C, 0},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, st33zp24_i2c_id);

 #ifdef CONFIG_OF
 static const struct of_device_id of_st33zp24_i2c_match[] = {
 	{ .compatible = "st,st33zp24-i2c", },
 	{}
 };
 MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match);
 #endif

 static SIMPLE_DEV_PM_OPS(st33zp24_i2c_ops, st33zp24_pm_suspend,
 			 st33zp24_pm_resume);

 static struct i2c_driver st33zp24_i2c_driver = {
 	.driver = {
 		.owner = THIS_MODULE,
 		.name = TPM_ST33_I2C,
 		.pm = &st33zp24_i2c_ops,
 		.of_match_table = of_match_ptr(of_st33zp24_i2c_match),
 	},
 	.probe = st33zp24_i2c_probe,
 	.remove = st33zp24_i2c_remove,
 	.id_table = st33zp24_i2c_id
 };

 module_i2c_driver(st33zp24_i2c_driver);

 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
 MODULE_DESCRIPTION("STM TPM 1.2 I2C ST33 Driver");
 MODULE_VERSION("1.3.0");
 MODULE_LICENSE("GPL");
	/*
	* STMicroelectronics TPM I2C Linux driver for TPM ST33ZP24
	* Copyright (C) 2009 - 2015 STMicroelectronics
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, see <http://www.gnu.org/licenses/>.
	*/

	#include <linux/module.h>
	#include <linux/i2c.h>
	#include <linux/gpio.h>
	#include <linux/of_irq.h>
	#include <linux/of_gpio.h>
	#include <linux/tpm.h>
	#include <linux/platform_data/st33zp24.h>

	#include "st33zp24.h"

	#define TPM_DUMMY_BYTE 0xAA

	struct st33zp24_i2c_phy {
	struct i2c_client *client;
	u8 buf[TPM_BUFSIZE + 1];
	int io_lpcpd;
	};

	/*
	* write8_reg
	* Send byte to the TIS register according to the ST33ZP24 I2C protocol.
	* @param: tpm_register, the tpm tis register where the data should be written
	* @param: tpm_data, the tpm_data to write inside the tpm_register
	* @param: tpm_size, The length of the data
	* @return: Returns negative errno, or else the number of bytes written.
	*/
	static int write8_reg(void phy_id, u8 tpm_register, u8 tpm_data, int tpm_size)
	{
	struct st33zp24_i2c_phy *phy = phy_id;

	phy->buf[0] = tpm_register;
	memcpy(phy->buf + 1, tpm_data, tpm_size);
	return i2c_master_send(phy->client, phy->buf, tpm_size + 1);
	} /* write8_reg() */

	/*
	* read8_reg
	* Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
	* @param: tpm_register, the tpm tis register where the data should be read
	* @param: tpm_data, the TPM response
	* @param: tpm_size, tpm TPM response size to read.
	* @return: number of byte read successfully: should be one if success.
	*/
	static int read8_reg(void phy_id, u8 tpm_register, u8 tpm_data, int tpm_size)
	{
	struct st33zp24_i2c_phy *phy = phy_id;
	u8 status = 0;
	u8 data;

	data = TPM_DUMMY_BYTE;
	status = write8_reg(phy, tpm_register, &data, 1);
	if (status == 2)
	status = i2c_master_recv(phy->client, tpm_data, tpm_size);
	return status;
	} /* read8_reg() */

	/*
	* st33zp24_i2c_send
	* Send byte to the TIS register according to the ST33ZP24 I2C protocol.
	* @param: phy_id, the phy description
	* @param: tpm_register, the tpm tis register where the data should be written
	* @param: tpm_data, the tpm_data to write inside the tpm_register
	* @param: tpm_size, the length of the data
	* @return: number of byte written successfully: should be one if success.
	*/
	static int st33zp24_i2c_send(void phy_id, u8 tpm_register, u8 tpm_data,
	int tpm_size)
	{
	return write8_reg(phy_id, tpm_register \| TPM_WRITE_DIRECTION, tpm_data,
	tpm_size);
	}

	/*
	* st33zp24_i2c_recv
	* Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
	* @param: phy_id, the phy description
	* @param: tpm_register, the tpm tis register where the data should be read
	* @param: tpm_data, the TPM response
	* @param: tpm_size, tpm TPM response size to read.
	* @return: number of byte read successfully: should be one if success.
	*/
	static int st33zp24_i2c_recv(void phy_id, u8 tpm_register, u8 tpm_data,
	int tpm_size)
	{
	return read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
	}

	static const struct st33zp24_phy_ops i2c_phy_ops = {
	.send = st33zp24_i2c_send,
	.recv = st33zp24_i2c_recv,
	};

	#ifdef CONFIG_OF
	static int st33zp24_i2c_of_request_resources(struct st33zp24_i2c_phy *phy)
	{
	struct device_node *pp;
	struct i2c_client *client = phy->client;
	int gpio;
	int ret;

	pp = client->dev.of_node;
	if (!pp) {
	dev_err(&client->dev, "No platform data\n");
	return -ENODEV;
	}

	/* Get GPIO from device tree */
	gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0);
	if (gpio < 0) {
	dev_err(&client->dev,
	"Failed to retrieve lpcpd-gpios from dts.\n");
	phy->io_lpcpd = -1;
	/*
	* lpcpd pin is not specified. This is not an issue as
	* power management can be also managed by TPM specific
	* commands. So leave with a success status code.
	*/
	return 0;
	}
	/* GPIO request and configuration */
	ret = devm_gpio_request_one(&client->dev, gpio,
	GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD");
	if (ret) {
	dev_err(&client->dev, "Failed to request lpcpd pin\n");
	return -ENODEV;
	}
	phy->io_lpcpd = gpio;

	return 0;
	}
	#else
	static int st33zp24_i2c_of_request_resources(struct st33zp24_i2c_phy *phy)
	{
	return -ENODEV;
	}
	#endif

	static int st33zp24_i2c_request_resources(struct i2c_client *client,
	struct st33zp24_i2c_phy *phy)
	{
	struct st33zp24_platform_data *pdata;
	int ret;

	pdata = client->dev.platform_data;
	if (!pdata) {
	dev_err(&client->dev, "No platform data\n");
	return -ENODEV;
	}

	/* store for late use */
	phy->io_lpcpd = pdata->io_lpcpd;

	if (gpio_is_valid(pdata->io_lpcpd)) {
	ret = devm_gpio_request_one(&client->dev,
	pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH,
	"TPM IO_LPCPD");
	if (ret) {
	dev_err(&client->dev, "Failed to request lpcpd pin\n");
	return ret;
	}
	}

	return 0;
	}

	/*
	* st33zp24_i2c_probe initialize the TPM device
	* @param: client, the i2c_client drescription (TPM I2C description).
	* @param: id, the i2c_device_id struct.
	* @return: 0 in case of success.
	* -1 in other case.
	*/
	static int st33zp24_i2c_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	int ret;
	struct st33zp24_platform_data *pdata;
	struct st33zp24_i2c_phy *phy;

	if (!client) {
	pr_info("%s: i2c client is NULL. Device not accessible.\n",
	__func__);
	return -ENODEV;
	}

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
	dev_info(&client->dev, "client not i2c capable\n");
	return -ENODEV;
	}

	phy = devm_kzalloc(&client->dev, sizeof(struct st33zp24_i2c_phy),
	GFP_KERNEL);
	if (!phy)
	return -ENOMEM;

	phy->client = client;
	pdata = client->dev.platform_data;
	if (!pdata && client->dev.of_node) {
	ret = st33zp24_i2c_of_request_resources(phy);
	if (ret)
	return ret;
	} else if (pdata) {
	ret = st33zp24_i2c_request_resources(client, phy);
	if (ret)
	return ret;
	}

	return st33zp24_probe(phy, &i2c_phy_ops, &client->dev, client->irq,
	phy->io_lpcpd);
	}

	/*
	* st33zp24_i2c_remove remove the TPM device
	* @param: client, the i2c_client description (TPM I2C description).
	* @return: 0 in case of success.
	*/
	static int st33zp24_i2c_remove(struct i2c_client *client)
	{
	struct tpm_chip *chip = i2c_get_clientdata(client);

	return st33zp24_remove(chip);
	}

	static const struct i2c_device_id st33zp24_i2c_id[] = {
	{TPM_ST33_I2C, 0},
	{}
	};
	MODULE_DEVICE_TABLE(i2c, st33zp24_i2c_id);

	#ifdef CONFIG_OF
	static const struct of_device_id of_st33zp24_i2c_match[] = {
	{ .compatible = "st,st33zp24-i2c", },
	{}
	};
	MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match);
	#endif

	static SIMPLE_DEV_PM_OPS(st33zp24_i2c_ops, st33zp24_pm_suspend,
	st33zp24_pm_resume);

	static struct i2c_driver st33zp24_i2c_driver = {
	.driver = {
	.owner = THIS_MODULE,
	.name = TPM_ST33_I2C,
	.pm = &st33zp24_i2c_ops,
	.of_match_table = of_match_ptr(of_st33zp24_i2c_match),
	},
	.probe = st33zp24_i2c_probe,
	.remove = st33zp24_i2c_remove,
	.id_table = st33zp24_i2c_id
	};

	module_i2c_driver(st33zp24_i2c_driver);

	MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
	MODULE_DESCRIPTION("STM TPM 1.2 I2C ST33 Driver");
	MODULE_VERSION("1.3.0");
	MODULE_LICENSE("GPL");