1 /* 2 * STMicroelectronics TPM I2C Linux driver for TPM ST33ZP24 3 * Copyright (C) 2009 - 2016 STMicroelectronics 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, see <http://www.gnu.org/licenses/>. 17 */ 18 19 #include <linux/module.h> 20 #include <linux/i2c.h> 21 #include <linux/gpio.h> 22 #include <linux/gpio/consumer.h> 23 #include <linux/of_irq.h> 24 #include <linux/of_gpio.h> 25 #include <linux/acpi.h> 26 #include <linux/tpm.h> 27 #include <linux/platform_data/st33zp24.h> 28 29 #include "../tpm.h" 30 #include "st33zp24.h" 31 32 #define TPM_DUMMY_BYTE 0xAA 33 34 struct st33zp24_i2c_phy { 35 struct i2c_client *client; 36 u8 buf[TPM_BUFSIZE + 1]; 37 int io_lpcpd; 38 }; 39 40 /* 41 * write8_reg 42 * Send byte to the TIS register according to the ST33ZP24 I2C protocol. 43 * @param: tpm_register, the tpm tis register where the data should be written 44 * @param: tpm_data, the tpm_data to write inside the tpm_register 45 * @param: tpm_size, The length of the data 46 * @return: Returns negative errno, or else the number of bytes written. 47 */ 48 static int write8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size) 49 { 50 struct st33zp24_i2c_phy *phy = phy_id; 51 52 phy->buf[0] = tpm_register; 53 memcpy(phy->buf + 1, tpm_data, tpm_size); 54 return i2c_master_send(phy->client, phy->buf, tpm_size + 1); 55 } /* write8_reg() */ 56 57 /* 58 * read8_reg 59 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol. 60 * @param: tpm_register, the tpm tis register where the data should be read 61 * @param: tpm_data, the TPM response 62 * @param: tpm_size, tpm TPM response size to read. 63 * @return: number of byte read successfully: should be one if success. 64 */ 65 static int read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size) 66 { 67 struct st33zp24_i2c_phy *phy = phy_id; 68 u8 status = 0; 69 u8 data; 70 71 data = TPM_DUMMY_BYTE; 72 status = write8_reg(phy, tpm_register, &data, 1); 73 if (status == 2) 74 status = i2c_master_recv(phy->client, tpm_data, tpm_size); 75 return status; 76 } /* read8_reg() */ 77 78 /* 79 * st33zp24_i2c_send 80 * Send byte to the TIS register according to the ST33ZP24 I2C protocol. 81 * @param: phy_id, the phy description 82 * @param: tpm_register, the tpm tis register where the data should be written 83 * @param: tpm_data, the tpm_data to write inside the tpm_register 84 * @param: tpm_size, the length of the data 85 * @return: number of byte written successfully: should be one if success. 86 */ 87 static int st33zp24_i2c_send(void *phy_id, u8 tpm_register, u8 *tpm_data, 88 int tpm_size) 89 { 90 return write8_reg(phy_id, tpm_register | TPM_WRITE_DIRECTION, tpm_data, 91 tpm_size); 92 } 93 94 /* 95 * st33zp24_i2c_recv 96 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol. 97 * @param: phy_id, the phy description 98 * @param: tpm_register, the tpm tis register where the data should be read 99 * @param: tpm_data, the TPM response 100 * @param: tpm_size, tpm TPM response size to read. 101 * @return: number of byte read successfully: should be one if success. 102 */ 103 static int st33zp24_i2c_recv(void *phy_id, u8 tpm_register, u8 *tpm_data, 104 int tpm_size) 105 { 106 return read8_reg(phy_id, tpm_register, tpm_data, tpm_size); 107 } 108 109 static const struct st33zp24_phy_ops i2c_phy_ops = { 110 .send = st33zp24_i2c_send, 111 .recv = st33zp24_i2c_recv, 112 }; 113 114 static const struct acpi_gpio_params lpcpd_gpios = { 1, 0, false }; 115 116 static const struct acpi_gpio_mapping acpi_st33zp24_gpios[] = { 117 { "lpcpd-gpios", &lpcpd_gpios, 1 }, 118 {}, 119 }; 120 121 static int st33zp24_i2c_acpi_request_resources(struct i2c_client *client) 122 { 123 struct tpm_chip *chip = i2c_get_clientdata(client); 124 struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev); 125 struct st33zp24_i2c_phy *phy = tpm_dev->phy_id; 126 struct gpio_desc *gpiod_lpcpd; 127 struct device *dev = &client->dev; 128 int ret; 129 130 ret = devm_acpi_dev_add_driver_gpios(dev, acpi_st33zp24_gpios); 131 if (ret) 132 return ret; 133 134 /* Get LPCPD GPIO from ACPI */ 135 gpiod_lpcpd = devm_gpiod_get(dev, "lpcpd", GPIOD_OUT_HIGH); 136 if (IS_ERR(gpiod_lpcpd)) { 137 dev_err(&client->dev, 138 "Failed to retrieve lpcpd-gpios from acpi.\n"); 139 phy->io_lpcpd = -1; 140 /* 141 * lpcpd pin is not specified. This is not an issue as 142 * power management can be also managed by TPM specific 143 * commands. So leave with a success status code. 144 */ 145 return 0; 146 } 147 148 phy->io_lpcpd = desc_to_gpio(gpiod_lpcpd); 149 150 return 0; 151 } 152 153 static int st33zp24_i2c_of_request_resources(struct i2c_client *client) 154 { 155 struct tpm_chip *chip = i2c_get_clientdata(client); 156 struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev); 157 struct st33zp24_i2c_phy *phy = tpm_dev->phy_id; 158 struct device_node *pp; 159 int gpio; 160 int ret; 161 162 pp = client->dev.of_node; 163 if (!pp) { 164 dev_err(&client->dev, "No platform data\n"); 165 return -ENODEV; 166 } 167 168 /* Get GPIO from device tree */ 169 gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0); 170 if (gpio < 0) { 171 dev_err(&client->dev, 172 "Failed to retrieve lpcpd-gpios from dts.\n"); 173 phy->io_lpcpd = -1; 174 /* 175 * lpcpd pin is not specified. This is not an issue as 176 * power management can be also managed by TPM specific 177 * commands. So leave with a success status code. 178 */ 179 return 0; 180 } 181 /* GPIO request and configuration */ 182 ret = devm_gpio_request_one(&client->dev, gpio, 183 GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD"); 184 if (ret) { 185 dev_err(&client->dev, "Failed to request lpcpd pin\n"); 186 return -ENODEV; 187 } 188 phy->io_lpcpd = gpio; 189 190 return 0; 191 } 192 193 static int st33zp24_i2c_request_resources(struct i2c_client *client) 194 { 195 struct tpm_chip *chip = i2c_get_clientdata(client); 196 struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev); 197 struct st33zp24_i2c_phy *phy = tpm_dev->phy_id; 198 struct st33zp24_platform_data *pdata; 199 int ret; 200 201 pdata = client->dev.platform_data; 202 if (!pdata) { 203 dev_err(&client->dev, "No platform data\n"); 204 return -ENODEV; 205 } 206 207 /* store for late use */ 208 phy->io_lpcpd = pdata->io_lpcpd; 209 210 if (gpio_is_valid(pdata->io_lpcpd)) { 211 ret = devm_gpio_request_one(&client->dev, 212 pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH, 213 "TPM IO_LPCPD"); 214 if (ret) { 215 dev_err(&client->dev, "Failed to request lpcpd pin\n"); 216 return ret; 217 } 218 } 219 220 return 0; 221 } 222 223 /* 224 * st33zp24_i2c_probe initialize the TPM device 225 * @param: client, the i2c_client drescription (TPM I2C description). 226 * @param: id, the i2c_device_id struct. 227 * @return: 0 in case of success. 228 * -1 in other case. 229 */ 230 static int st33zp24_i2c_probe(struct i2c_client *client, 231 const struct i2c_device_id *id) 232 { 233 int ret; 234 struct st33zp24_platform_data *pdata; 235 struct st33zp24_i2c_phy *phy; 236 237 if (!client) { 238 pr_info("%s: i2c client is NULL. Device not accessible.\n", 239 __func__); 240 return -ENODEV; 241 } 242 243 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 244 dev_info(&client->dev, "client not i2c capable\n"); 245 return -ENODEV; 246 } 247 248 phy = devm_kzalloc(&client->dev, sizeof(struct st33zp24_i2c_phy), 249 GFP_KERNEL); 250 if (!phy) 251 return -ENOMEM; 252 253 phy->client = client; 254 255 pdata = client->dev.platform_data; 256 if (!pdata && client->dev.of_node) { 257 ret = st33zp24_i2c_of_request_resources(client); 258 if (ret) 259 return ret; 260 } else if (pdata) { 261 ret = st33zp24_i2c_request_resources(client); 262 if (ret) 263 return ret; 264 } else if (ACPI_HANDLE(&client->dev)) { 265 ret = st33zp24_i2c_acpi_request_resources(client); 266 if (ret) 267 return ret; 268 } 269 270 return st33zp24_probe(phy, &i2c_phy_ops, &client->dev, client->irq, 271 phy->io_lpcpd); 272 } 273 274 /* 275 * st33zp24_i2c_remove remove the TPM device 276 * @param: client, the i2c_client description (TPM I2C description). 277 * @return: 0 in case of success. 278 */ 279 static int st33zp24_i2c_remove(struct i2c_client *client) 280 { 281 struct tpm_chip *chip = i2c_get_clientdata(client); 282 int ret; 283 284 ret = st33zp24_remove(chip); 285 if (ret) 286 return ret; 287 288 return 0; 289 } 290 291 static const struct i2c_device_id st33zp24_i2c_id[] = { 292 {TPM_ST33_I2C, 0}, 293 {} 294 }; 295 MODULE_DEVICE_TABLE(i2c, st33zp24_i2c_id); 296 297 static const struct of_device_id of_st33zp24_i2c_match[] = { 298 { .compatible = "st,st33zp24-i2c", }, 299 {} 300 }; 301 MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match); 302 303 static const struct acpi_device_id st33zp24_i2c_acpi_match[] = { 304 {"SMO3324"}, 305 {} 306 }; 307 MODULE_DEVICE_TABLE(acpi, st33zp24_i2c_acpi_match); 308 309 static SIMPLE_DEV_PM_OPS(st33zp24_i2c_ops, st33zp24_pm_suspend, 310 st33zp24_pm_resume); 311 312 static struct i2c_driver st33zp24_i2c_driver = { 313 .driver = { 314 .name = TPM_ST33_I2C, 315 .pm = &st33zp24_i2c_ops, 316 .of_match_table = of_match_ptr(of_st33zp24_i2c_match), 317 .acpi_match_table = ACPI_PTR(st33zp24_i2c_acpi_match), 318 }, 319 .probe = st33zp24_i2c_probe, 320 .remove = st33zp24_i2c_remove, 321 .id_table = st33zp24_i2c_id 322 }; 323 324 module_i2c_driver(st33zp24_i2c_driver); 325 326 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)"); 327 MODULE_DESCRIPTION("STM TPM 1.2 I2C ST33 Driver"); 328 MODULE_VERSION("1.3.0"); 329 MODULE_LICENSE("GPL"); 330