1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * STMicroelectronics TPM I2C Linux driver for TPM ST33ZP24
4 * Copyright (C) 2009 - 2016 STMicroelectronics
5 */
6
7#include <linux/module.h>
8#include <linux/i2c.h>
9#include <linux/of.h>
10#include <linux/acpi.h>
11#include <linux/tpm.h>
12
13#include "../tpm.h"
14#include "st33zp24.h"
15
16#define TPM_DUMMY_BYTE 0xAA
17
18struct st33zp24_i2c_phy {
19 struct i2c_client *client;
20 u8 buf[ST33ZP24_BUFSIZE + 1];
21};
22
23/*
24 * write8_reg
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.
30 */
31static int write8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
32{
33 struct st33zp24_i2c_phy *phy = phy_id;
34
35 phy->buf[0] = tpm_register;
36 memcpy(phy->buf + 1, tpm_data, tpm_size);
37 return i2c_master_send(client: phy->client, buf: phy->buf, count: tpm_size + 1);
38} /* write8_reg() */
39
40/*
41 * read8_reg
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.
47 */
48static int read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
49{
50 struct st33zp24_i2c_phy *phy = phy_id;
51 u8 status = 0;
52 u8 data;
53
54 data = TPM_DUMMY_BYTE;
55 status = write8_reg(phy_id: phy, tpm_register, tpm_data: &data, tpm_size: 1);
56 if (status == 2)
57 status = i2c_master_recv(client: phy->client, buf: tpm_data, count: tpm_size);
58 return status;
59} /* read8_reg() */
60
61/*
62 * st33zp24_i2c_send
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.
69 */
70static int st33zp24_i2c_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
71 int tpm_size)
72{
73 return write8_reg(phy_id, tpm_register: tpm_register | TPM_WRITE_DIRECTION, tpm_data,
74 tpm_size);
75}
76
77/*
78 * st33zp24_i2c_recv
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.
85 */
86static int st33zp24_i2c_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
87 int tpm_size)
88{
89 return read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
90}
91
92static const struct st33zp24_phy_ops i2c_phy_ops = {
93 .send = st33zp24_i2c_send,
94 .recv = st33zp24_i2c_recv,
95};
96
97/*
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.
102 * -1 in other case.
103 */
104static int st33zp24_i2c_probe(struct i2c_client *client)
105{
106 struct st33zp24_i2c_phy *phy;
107
108 if (!i2c_check_functionality(adap: client->adapter, I2C_FUNC_I2C)) {
109 dev_info(&client->dev, "client not i2c capable\n");
110 return -ENODEV;
111 }
112
113 phy = devm_kzalloc(dev: &client->dev, size: sizeof(struct st33zp24_i2c_phy),
114 GFP_KERNEL);
115 if (!phy)
116 return -ENOMEM;
117
118 phy->client = client;
119
120 return st33zp24_probe(phy_id: phy, ops: &i2c_phy_ops, dev: &client->dev, irq: client->irq);
121}
122
123/*
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.
127 */
128static void st33zp24_i2c_remove(struct i2c_client *client)
129{
130 struct tpm_chip *chip = i2c_get_clientdata(client);
131
132 st33zp24_remove(chip);
133}
134
135static const struct i2c_device_id st33zp24_i2c_id[] = {
136 {TPM_ST33_I2C, 0},
137 {}
138};
139MODULE_DEVICE_TABLE(i2c, st33zp24_i2c_id);
140
141static const struct of_device_id of_st33zp24_i2c_match[] __maybe_unused = {
142 { .compatible = "st,st33zp24-i2c", },
143 {}
144};
145MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match);
146
147static const struct acpi_device_id st33zp24_i2c_acpi_match[] __maybe_unused = {
148 {"SMO3324"},
149 {}
150};
151MODULE_DEVICE_TABLE(acpi, st33zp24_i2c_acpi_match);
152
153static SIMPLE_DEV_PM_OPS(st33zp24_i2c_ops, st33zp24_pm_suspend,
154 st33zp24_pm_resume);
155
156static struct i2c_driver st33zp24_i2c_driver = {
157 .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),
162 },
163 .probe = st33zp24_i2c_probe,
164 .remove = st33zp24_i2c_remove,
165 .id_table = st33zp24_i2c_id
166};
167
168module_i2c_driver(st33zp24_i2c_driver);
169
170MODULE_AUTHOR("TPM support <TPMsupport@list.st.com>");
171MODULE_DESCRIPTION("STM TPM 1.2 I2C ST33 Driver");
172MODULE_VERSION("1.3.0");
173MODULE_LICENSE("GPL");
174

source code of linux/drivers/char/tpm/st33zp24/i2c.c