diff options
Diffstat (limited to 'drivers/char/tpm/st33zp24/i2c.c')
| -rw-r--r-- | drivers/char/tpm/st33zp24/i2c.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/drivers/char/tpm/st33zp24/i2c.c b/drivers/char/tpm/st33zp24/i2c.c new file mode 100644 index 0000000000..661574bb0a --- /dev/null +++ b/drivers/char/tpm/st33zp24/i2c.c @@ -0,0 +1,173 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * STMicroelectronics TPM I2C Linux driver for TPM ST33ZP24 + * Copyright (C) 2009 - 2016 STMicroelectronics + */ + +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/of.h> +#include <linux/acpi.h> +#include <linux/tpm.h> + +#include "../tpm.h" +#include "st33zp24.h" + +#define TPM_DUMMY_BYTE 0xAA + +struct st33zp24_i2c_phy { + struct i2c_client *client; + u8 buf[ST33ZP24_BUFSIZE + 1]; +}; + +/* + * 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, +}; + +/* + * st33zp24_i2c_probe initialize the TPM device + * @param: client, the i2c_client description (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) +{ + struct st33zp24_i2c_phy *phy; + + 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; + + return st33zp24_probe(phy, &i2c_phy_ops, &client->dev, client->irq); +} + +/* + * st33zp24_i2c_remove remove the TPM device + * @param: client, the i2c_client description (TPM I2C description). + * @return: 0 in case of success. + */ +static void st33zp24_i2c_remove(struct i2c_client *client) +{ + struct tpm_chip *chip = i2c_get_clientdata(client); + + st33zp24_remove(chip); +} + +static const struct i2c_device_id st33zp24_i2c_id[] = { + {TPM_ST33_I2C, 0}, + {} +}; +MODULE_DEVICE_TABLE(i2c, st33zp24_i2c_id); + +static const struct of_device_id of_st33zp24_i2c_match[] __maybe_unused = { + { .compatible = "st,st33zp24-i2c", }, + {} +}; +MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match); + +static const struct acpi_device_id st33zp24_i2c_acpi_match[] __maybe_unused = { + {"SMO3324"}, + {} +}; +MODULE_DEVICE_TABLE(acpi, st33zp24_i2c_acpi_match); + +static SIMPLE_DEV_PM_OPS(st33zp24_i2c_ops, st33zp24_pm_suspend, + st33zp24_pm_resume); + +static struct i2c_driver st33zp24_i2c_driver = { + .driver = { + .name = TPM_ST33_I2C, + .pm = &st33zp24_i2c_ops, + .of_match_table = of_match_ptr(of_st33zp24_i2c_match), + .acpi_match_table = ACPI_PTR(st33zp24_i2c_acpi_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"); |