1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * STMicroelectronics TPM I2C Linux driver for TPM ST33ZP24
4 * Copyright (C) 2009 - 2016 STMicroelectronics
7 #include <linux/module.h>
10 #include <linux/acpi.h>
11 #include <linux/tpm.h>
16 #define TPM_DUMMY_BYTE 0xAA
18 struct st33zp24_i2c_phy {
19 struct i2c_client *client;
20 u8 buf[ST33ZP24_BUFSIZE + 1];
25 * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
26 * @param: tpm_register, the tpm tis register where the data should be written
27 * @param: tpm_data, the tpm_data to write inside the tpm_register
28 * @param: tpm_size, The length of the data
29 * @return: Returns negative errno, or else the number of bytes written.
31 static int write8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
33 struct st33zp24_i2c_phy *phy = phy_id;
35 phy->buf[0] = tpm_register;
36 memcpy(phy->buf + 1, tpm_data, tpm_size);
37 return i2c_master_send(phy->client, phy->buf, tpm_size + 1);
42 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
43 * @param: tpm_register, the tpm tis register where the data should be read
44 * @param: tpm_data, the TPM response
45 * @param: tpm_size, tpm TPM response size to read.
46 * @return: number of byte read successfully: should be one if success.
48 static int read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
50 struct st33zp24_i2c_phy *phy = phy_id;
54 data = TPM_DUMMY_BYTE;
55 status = write8_reg(phy, tpm_register, &data, 1);
57 status = i2c_master_recv(phy->client, tpm_data, tpm_size);
63 * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
64 * @param: phy_id, the phy description
65 * @param: tpm_register, the tpm tis register where the data should be written
66 * @param: tpm_data, the tpm_data to write inside the tpm_register
67 * @param: tpm_size, the length of the data
68 * @return: number of byte written successfully: should be one if success.
70 static int st33zp24_i2c_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
73 return write8_reg(phy_id, tpm_register | TPM_WRITE_DIRECTION, tpm_data,
79 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
80 * @param: phy_id, the phy description
81 * @param: tpm_register, the tpm tis register where the data should be read
82 * @param: tpm_data, the TPM response
83 * @param: tpm_size, tpm TPM response size to read.
84 * @return: number of byte read successfully: should be one if success.
86 static int st33zp24_i2c_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
89 return read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
92 static const struct st33zp24_phy_ops i2c_phy_ops = {
93 .send = st33zp24_i2c_send,
94 .recv = st33zp24_i2c_recv,
98 * st33zp24_i2c_probe initialize the TPM device
99 * @param: client, the i2c_client description (TPM I2C description).
100 * @param: id, the i2c_device_id struct.
101 * @return: 0 in case of success.
104 static int st33zp24_i2c_probe(struct i2c_client *client)
106 struct st33zp24_i2c_phy *phy;
108 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
109 dev_info(&client->dev, "client not i2c capable\n");
113 phy = devm_kzalloc(&client->dev, sizeof(struct st33zp24_i2c_phy),
118 phy->client = client;
120 return st33zp24_probe(phy, &i2c_phy_ops, &client->dev, client->irq);
124 * st33zp24_i2c_remove remove the TPM device
125 * @param: client, the i2c_client description (TPM I2C description).
126 * @return: 0 in case of success.
128 static void st33zp24_i2c_remove(struct i2c_client *client)
130 struct tpm_chip *chip = i2c_get_clientdata(client);
132 st33zp24_remove(chip);
135 static const struct i2c_device_id st33zp24_i2c_id[] = {
139 MODULE_DEVICE_TABLE(i2c, st33zp24_i2c_id);
141 static const struct of_device_id of_st33zp24_i2c_match[] = {
142 { .compatible = "st,st33zp24-i2c", },
145 MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match);
147 static const struct acpi_device_id st33zp24_i2c_acpi_match[] = {
151 MODULE_DEVICE_TABLE(acpi, st33zp24_i2c_acpi_match);
153 static SIMPLE_DEV_PM_OPS(st33zp24_i2c_ops, st33zp24_pm_suspend,
156 static struct i2c_driver st33zp24_i2c_driver = {
158 .name = TPM_ST33_I2C,
159 .pm = &st33zp24_i2c_ops,
160 .of_match_table = of_match_ptr(of_st33zp24_i2c_match),
161 .acpi_match_table = ACPI_PTR(st33zp24_i2c_acpi_match),
163 .probe_new = st33zp24_i2c_probe,
164 .remove = st33zp24_i2c_remove,
165 .id_table = st33zp24_i2c_id
168 module_i2c_driver(st33zp24_i2c_driver);
170 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
171 MODULE_DESCRIPTION("STM TPM 1.2 I2C ST33 Driver");
172 MODULE_VERSION("1.3.0");
173 MODULE_LICENSE("GPL");