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/gpio.h> 10 #include <linux/gpio/consumer.h> 11 #include <linux/of_irq.h> 12 #include <linux/of_gpio.h> 13 #include <linux/acpi.h> 14 #include <linux/tpm.h> 15 #include <linux/platform_data/st33zp24.h> 16 17 #include "../tpm.h" 18 #include "st33zp24.h" 19 20 #define TPM_DUMMY_BYTE 0xAA 21 22 struct st33zp24_i2c_phy { 23 struct i2c_client *client; 24 u8 buf[ST33ZP24_BUFSIZE + 1]; 25 int io_lpcpd; 26 }; 27 28 /* 29 * write8_reg 30 * Send byte to the TIS register according to the ST33ZP24 I2C protocol. 31 * @param: tpm_register, the tpm tis register where the data should be written 32 * @param: tpm_data, the tpm_data to write inside the tpm_register 33 * @param: tpm_size, The length of the data 34 * @return: Returns negative errno, or else the number of bytes written. 35 */ 36 static int write8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size) 37 { 38 struct st33zp24_i2c_phy *phy = phy_id; 39 40 phy->buf[0] = tpm_register; 41 memcpy(phy->buf + 1, tpm_data, tpm_size); 42 return i2c_master_send(phy->client, phy->buf, tpm_size + 1); 43 } /* write8_reg() */ 44 45 /* 46 * read8_reg 47 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol. 48 * @param: tpm_register, the tpm tis register where the data should be read 49 * @param: tpm_data, the TPM response 50 * @param: tpm_size, tpm TPM response size to read. 51 * @return: number of byte read successfully: should be one if success. 52 */ 53 static int read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size) 54 { 55 struct st33zp24_i2c_phy *phy = phy_id; 56 u8 status = 0; 57 u8 data; 58 59 data = TPM_DUMMY_BYTE; 60 status = write8_reg(phy, tpm_register, &data, 1); 61 if (status == 2) 62 status = i2c_master_recv(phy->client, tpm_data, tpm_size); 63 return status; 64 } /* read8_reg() */ 65 66 /* 67 * st33zp24_i2c_send 68 * Send byte to the TIS register according to the ST33ZP24 I2C protocol. 69 * @param: phy_id, the phy description 70 * @param: tpm_register, the tpm tis register where the data should be written 71 * @param: tpm_data, the tpm_data to write inside the tpm_register 72 * @param: tpm_size, the length of the data 73 * @return: number of byte written successfully: should be one if success. 74 */ 75 static int st33zp24_i2c_send(void *phy_id, u8 tpm_register, u8 *tpm_data, 76 int tpm_size) 77 { 78 return write8_reg(phy_id, tpm_register | TPM_WRITE_DIRECTION, tpm_data, 79 tpm_size); 80 } 81 82 /* 83 * st33zp24_i2c_recv 84 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol. 85 * @param: phy_id, the phy description 86 * @param: tpm_register, the tpm tis register where the data should be read 87 * @param: tpm_data, the TPM response 88 * @param: tpm_size, tpm TPM response size to read. 89 * @return: number of byte read successfully: should be one if success. 90 */ 91 static int st33zp24_i2c_recv(void *phy_id, u8 tpm_register, u8 *tpm_data, 92 int tpm_size) 93 { 94 return read8_reg(phy_id, tpm_register, tpm_data, tpm_size); 95 } 96 97 static const struct st33zp24_phy_ops i2c_phy_ops = { 98 .send = st33zp24_i2c_send, 99 .recv = st33zp24_i2c_recv, 100 }; 101 102 static const struct acpi_gpio_params lpcpd_gpios = { 1, 0, false }; 103 104 static const struct acpi_gpio_mapping acpi_st33zp24_gpios[] = { 105 { "lpcpd-gpios", &lpcpd_gpios, 1 }, 106 {}, 107 }; 108 109 static int st33zp24_i2c_acpi_request_resources(struct i2c_client *client) 110 { 111 struct tpm_chip *chip = i2c_get_clientdata(client); 112 struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev); 113 struct st33zp24_i2c_phy *phy = tpm_dev->phy_id; 114 struct gpio_desc *gpiod_lpcpd; 115 struct device *dev = &client->dev; 116 int ret; 117 118 ret = devm_acpi_dev_add_driver_gpios(dev, acpi_st33zp24_gpios); 119 if (ret) 120 return ret; 121 122 /* Get LPCPD GPIO from ACPI */ 123 gpiod_lpcpd = devm_gpiod_get(dev, "lpcpd", GPIOD_OUT_HIGH); 124 if (IS_ERR(gpiod_lpcpd)) { 125 dev_err(&client->dev, 126 "Failed to retrieve lpcpd-gpios from acpi.\n"); 127 phy->io_lpcpd = -1; 128 /* 129 * lpcpd pin is not specified. This is not an issue as 130 * power management can be also managed by TPM specific 131 * commands. So leave with a success status code. 132 */ 133 return 0; 134 } 135 136 phy->io_lpcpd = desc_to_gpio(gpiod_lpcpd); 137 138 return 0; 139 } 140 141 static int st33zp24_i2c_of_request_resources(struct i2c_client *client) 142 { 143 struct tpm_chip *chip = i2c_get_clientdata(client); 144 struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev); 145 struct st33zp24_i2c_phy *phy = tpm_dev->phy_id; 146 struct device_node *pp; 147 int gpio; 148 int ret; 149 150 pp = client->dev.of_node; 151 if (!pp) { 152 dev_err(&client->dev, "No platform data\n"); 153 return -ENODEV; 154 } 155 156 /* Get GPIO from device tree */ 157 gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0); 158 if (gpio < 0) { 159 dev_err(&client->dev, 160 "Failed to retrieve lpcpd-gpios from dts.\n"); 161 phy->io_lpcpd = -1; 162 /* 163 * lpcpd pin is not specified. This is not an issue as 164 * power management can be also managed by TPM specific 165 * commands. So leave with a success status code. 166 */ 167 return 0; 168 } 169 /* GPIO request and configuration */ 170 ret = devm_gpio_request_one(&client->dev, gpio, 171 GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD"); 172 if (ret) { 173 dev_err(&client->dev, "Failed to request lpcpd pin\n"); 174 return -ENODEV; 175 } 176 phy->io_lpcpd = gpio; 177 178 return 0; 179 } 180 181 static int st33zp24_i2c_request_resources(struct i2c_client *client) 182 { 183 struct tpm_chip *chip = i2c_get_clientdata(client); 184 struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev); 185 struct st33zp24_i2c_phy *phy = tpm_dev->phy_id; 186 struct st33zp24_platform_data *pdata; 187 int ret; 188 189 pdata = client->dev.platform_data; 190 if (!pdata) { 191 dev_err(&client->dev, "No platform data\n"); 192 return -ENODEV; 193 } 194 195 /* store for late use */ 196 phy->io_lpcpd = pdata->io_lpcpd; 197 198 if (gpio_is_valid(pdata->io_lpcpd)) { 199 ret = devm_gpio_request_one(&client->dev, 200 pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH, 201 "TPM IO_LPCPD"); 202 if (ret) { 203 dev_err(&client->dev, "Failed to request lpcpd pin\n"); 204 return ret; 205 } 206 } 207 208 return 0; 209 } 210 211 /* 212 * st33zp24_i2c_probe initialize the TPM device 213 * @param: client, the i2c_client drescription (TPM I2C description). 214 * @param: id, the i2c_device_id struct. 215 * @return: 0 in case of success. 216 * -1 in other case. 217 */ 218 static int st33zp24_i2c_probe(struct i2c_client *client, 219 const struct i2c_device_id *id) 220 { 221 int ret; 222 struct st33zp24_platform_data *pdata; 223 struct st33zp24_i2c_phy *phy; 224 225 if (!client) { 226 pr_info("%s: i2c client is NULL. Device not accessible.\n", 227 __func__); 228 return -ENODEV; 229 } 230 231 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 232 dev_info(&client->dev, "client not i2c capable\n"); 233 return -ENODEV; 234 } 235 236 phy = devm_kzalloc(&client->dev, sizeof(struct st33zp24_i2c_phy), 237 GFP_KERNEL); 238 if (!phy) 239 return -ENOMEM; 240 241 phy->client = client; 242 243 pdata = client->dev.platform_data; 244 if (!pdata && client->dev.of_node) { 245 ret = st33zp24_i2c_of_request_resources(client); 246 if (ret) 247 return ret; 248 } else if (pdata) { 249 ret = st33zp24_i2c_request_resources(client); 250 if (ret) 251 return ret; 252 } else if (ACPI_HANDLE(&client->dev)) { 253 ret = st33zp24_i2c_acpi_request_resources(client); 254 if (ret) 255 return ret; 256 } 257 258 return st33zp24_probe(phy, &i2c_phy_ops, &client->dev, client->irq, 259 phy->io_lpcpd); 260 } 261 262 /* 263 * st33zp24_i2c_remove remove the TPM device 264 * @param: client, the i2c_client description (TPM I2C description). 265 * @return: 0 in case of success. 266 */ 267 static int st33zp24_i2c_remove(struct i2c_client *client) 268 { 269 struct tpm_chip *chip = i2c_get_clientdata(client); 270 int ret; 271 272 ret = st33zp24_remove(chip); 273 if (ret) 274 return ret; 275 276 return 0; 277 } 278 279 static const struct i2c_device_id st33zp24_i2c_id[] = { 280 {TPM_ST33_I2C, 0}, 281 {} 282 }; 283 MODULE_DEVICE_TABLE(i2c, st33zp24_i2c_id); 284 285 static const struct of_device_id of_st33zp24_i2c_match[] = { 286 { .compatible = "st,st33zp24-i2c", }, 287 {} 288 }; 289 MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match); 290 291 static const struct acpi_device_id st33zp24_i2c_acpi_match[] = { 292 {"SMO3324"}, 293 {} 294 }; 295 MODULE_DEVICE_TABLE(acpi, st33zp24_i2c_acpi_match); 296 297 static SIMPLE_DEV_PM_OPS(st33zp24_i2c_ops, st33zp24_pm_suspend, 298 st33zp24_pm_resume); 299 300 static struct i2c_driver st33zp24_i2c_driver = { 301 .driver = { 302 .name = TPM_ST33_I2C, 303 .pm = &st33zp24_i2c_ops, 304 .of_match_table = of_match_ptr(of_st33zp24_i2c_match), 305 .acpi_match_table = ACPI_PTR(st33zp24_i2c_acpi_match), 306 }, 307 .probe = st33zp24_i2c_probe, 308 .remove = st33zp24_i2c_remove, 309 .id_table = st33zp24_i2c_id 310 }; 311 312 module_i2c_driver(st33zp24_i2c_driver); 313 314 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)"); 315 MODULE_DESCRIPTION("STM TPM 1.2 I2C ST33 Driver"); 316 MODULE_VERSION("1.3.0"); 317 MODULE_LICENSE("GPL"); 318