drivers/char/tpm/st33zp24/i2c.c

   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");