diff options
Diffstat (limited to 'drivers/char/tpm/st33zp24/i2c.c')
| -rw-r--r-- | drivers/char/tpm/st33zp24/i2c.c | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/drivers/char/tpm/st33zp24/i2c.c b/drivers/char/tpm/st33zp24/i2c.c new file mode 100644 index 000000000000..ad1ee180e0c2 --- /dev/null +++ b/drivers/char/tpm/st33zp24/i2c.c @@ -0,0 +1,276 @@ +/* + * 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"); |
