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 18 struct 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 */ 31 static 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 */ 48 static 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 */ 70 static 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 */ 86 static 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 92 static 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 */ 104 static 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 */ 128 static void st33zp24_i2c_remove(struct i2c_client *client) 129 { 130 struct tpm_chip *chip = i2c_get_clientdata(client); 131 132 st33zp24_remove(chip); 133 } 134 135 static const struct i2c_device_id st33zp24_i2c_id[] = { 136 {TPM_ST33_I2C, 0}, 137 {} 138 }; 139 MODULE_DEVICE_TABLE(i2c, st33zp24_i2c_id); 140 141 static const struct of_device_id of_st33zp24_i2c_match[] __maybe_unused = { 142 { .compatible = "st,st33zp24-i2c", }, 143 {} 144 }; 145 MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match); 146 147 static const struct acpi_device_id st33zp24_i2c_acpi_match[] __maybe_unused = { 148 {"SMO3324"}, 149 {} 150 }; 151 MODULE_DEVICE_TABLE(acpi, st33zp24_i2c_acpi_match); 152 153 static SIMPLE_DEV_PM_OPS(st33zp24_i2c_ops, st33zp24_pm_suspend, 154 st33zp24_pm_resume); 155 156 static 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 }; 167 168 module_i2c_driver(st33zp24_i2c_driver); 169 170 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"); 174