i2c.c

  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(phy->client, phy->buf, 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, tpm_register, &data, 1);
 56	if (status == 2)
 57		status = i2c_master_recv(phy->client, tpm_data, 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_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(client->adapter, I2C_FUNC_I2C)) {
109		dev_info(&client->dev, "client not i2c capable\n");
110		return -ENODEV;
111	}
112
113	phy = devm_kzalloc(&client->dev, 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, &i2c_phy_ops, &client->dev, 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 },
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");