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 int st33zp24_i2c_acpi_request_resources(struct i2c_client *client) 115 { 116 struct tpm_chip *chip = i2c_get_clientdata(client); 117 struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev); 118 struct st33zp24_i2c_phy *phy = tpm_dev->phy_id; 119 struct gpio_desc *gpiod_lpcpd; 120 struct device *dev = &client->dev; 121 122 /* Get LPCPD GPIO from ACPI */ 123 gpiod_lpcpd = devm_gpiod_get_index(dev, "TPM IO LPCPD", 1, 124 GPIOD_OUT_HIGH); 125 if (IS_ERR(gpiod_lpcpd)) { 126 dev_err(&client->dev, 127 "Failed to retrieve lpcpd-gpios from acpi.\n"); 128 phy->io_lpcpd = -1; 129 /* 130 * lpcpd pin is not specified. This is not an issue as 131 * power management can be also managed by TPM specific 132 * commands. So leave with a success status code. 133 */ 134 return 0; 135 } 136 137 phy->io_lpcpd = desc_to_gpio(gpiod_lpcpd); 138 139 return 0; 140 } 141 142 static int st33zp24_i2c_of_request_resources(struct i2c_client *client) 143 { 144 struct tpm_chip *chip = i2c_get_clientdata(client); 145 struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev); 146 struct st33zp24_i2c_phy *phy = tpm_dev->phy_id; 147 struct device_node *pp; 148 int gpio; 149 int ret; 150 151 pp = client->dev.of_node; 152 if (!pp) { 153 dev_err(&client->dev, "No platform data\n"); 154 return -ENODEV; 155 } 156 157 /* Get GPIO from device tree */ 158 gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0); 159 if (gpio < 0) { 160 dev_err(&client->dev, 161 "Failed to retrieve lpcpd-gpios from dts.\n"); 162 phy->io_lpcpd = -1; 163 /* 164 * lpcpd pin is not specified. This is not an issue as 165 * power management can be also managed by TPM specific 166 * commands. So leave with a success status code. 167 */ 168 return 0; 169 } 170 /* GPIO request and configuration */ 171 ret = devm_gpio_request_one(&client->dev, gpio, 172 GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD"); 173 if (ret) { 174 dev_err(&client->dev, "Failed to request lpcpd pin\n"); 175 return -ENODEV; 176 } 177 phy->io_lpcpd = gpio; 178 179 return 0; 180 } 181 182 static int st33zp24_i2c_request_resources(struct i2c_client *client) 183 { 184 struct tpm_chip *chip = i2c_get_clientdata(client); 185 struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev); 186 struct st33zp24_i2c_phy *phy = tpm_dev->phy_id; 187 struct st33zp24_platform_data *pdata; 188 int ret; 189 190 pdata = client->dev.platform_data; 191 if (!pdata) { 192 dev_err(&client->dev, "No platform data\n"); 193 return -ENODEV; 194 } 195 196 /* store for late use */ 197 phy->io_lpcpd = pdata->io_lpcpd; 198 199 if (gpio_is_valid(pdata->io_lpcpd)) { 200 ret = devm_gpio_request_one(&client->dev, 201 pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH, 202 "TPM IO_LPCPD"); 203 if (ret) { 204 dev_err(&client->dev, "Failed to request lpcpd pin\n"); 205 return ret; 206 } 207 } 208 209 return 0; 210 } 211 212 /* 213 * st33zp24_i2c_probe initialize the TPM device 214 * @param: client, the i2c_client drescription (TPM I2C description). 215 * @param: id, the i2c_device_id struct. 216 * @return: 0 in case of success. 217 * -1 in other case. 218 */ 219 static int st33zp24_i2c_probe(struct i2c_client *client, 220 const struct i2c_device_id *id) 221 { 222 int ret; 223 struct st33zp24_platform_data *pdata; 224 struct st33zp24_i2c_phy *phy; 225 226 if (!client) { 227 pr_info("%s: i2c client is NULL. Device not accessible.\n", 228 __func__); 229 return -ENODEV; 230 } 231 232 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { 233 dev_info(&client->dev, "client not i2c capable\n"); 234 return -ENODEV; 235 } 236 237 phy = devm_kzalloc(&client->dev, sizeof(struct st33zp24_i2c_phy), 238 GFP_KERNEL); 239 if (!phy) 240 return -ENOMEM; 241 242 phy->client = client; 243 244 pdata = client->dev.platform_data; 245 if (!pdata && client->dev.of_node) { 246 ret = st33zp24_i2c_of_request_resources(client); 247 if (ret) 248 return ret; 249 } else if (pdata) { 250 ret = st33zp24_i2c_request_resources(client); 251 if (ret) 252 return ret; 253 } else if (ACPI_HANDLE(&client->dev)) { 254 ret = st33zp24_i2c_acpi_request_resources(client); 255 if (ret) 256 return ret; 257 } 258 259 return st33zp24_probe(phy, &i2c_phy_ops, &client->dev, client->irq, 260 phy->io_lpcpd); 261 } 262 263 /* 264 * st33zp24_i2c_remove remove the TPM device 265 * @param: client, the i2c_client description (TPM I2C description). 266 * @return: 0 in case of success. 267 */ 268 static int st33zp24_i2c_remove(struct i2c_client *client) 269 { 270 struct tpm_chip *chip = i2c_get_clientdata(client); 271 272 return st33zp24_remove(chip); 273 } 274 275 static const struct i2c_device_id st33zp24_i2c_id[] = { 276 {TPM_ST33_I2C, 0}, 277 {} 278 }; 279 MODULE_DEVICE_TABLE(i2c, st33zp24_i2c_id); 280 281 static const struct of_device_id of_st33zp24_i2c_match[] = { 282 { .compatible = "st,st33zp24-i2c", }, 283 {} 284 }; 285 MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match); 286 287 static const struct acpi_device_id st33zp24_i2c_acpi_match[] = { 288 {"SMO3324"}, 289 {} 290 }; 291 MODULE_DEVICE_TABLE(acpi, st33zp24_i2c_acpi_match); 292 293 static SIMPLE_DEV_PM_OPS(st33zp24_i2c_ops, st33zp24_pm_suspend, 294 st33zp24_pm_resume); 295 296 static struct i2c_driver st33zp24_i2c_driver = { 297 .driver = { 298 .name = TPM_ST33_I2C, 299 .pm = &st33zp24_i2c_ops, 300 .of_match_table = of_match_ptr(of_st33zp24_i2c_match), 301 .acpi_match_table = ACPI_PTR(st33zp24_i2c_acpi_match), 302 }, 303 .probe = st33zp24_i2c_probe, 304 .remove = st33zp24_i2c_remove, 305 .id_table = st33zp24_i2c_id 306 }; 307 308 module_i2c_driver(st33zp24_i2c_driver); 309 310 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)"); 311 MODULE_DESCRIPTION("STM TPM 1.2 I2C ST33 Driver"); 312 MODULE_VERSION("1.3.0"); 313 MODULE_LICENSE("GPL"); 314