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| 1 | +/* |
| 2 | + * STMicroelectronics TPM I2C Linux driver for TPM ST33ZP24 |
| 3 | + * Copyright (C) 2009 - 2015 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/of_irq.h> |
| 23 | +#include <linux/of_gpio.h> |
| 24 | +#include <linux/tpm.h> |
| 25 | +#include <linux/platform_data/st33zp24.h> |
| 26 | + |
| 27 | +#include "st33zp24.h" |
| 28 | + |
| 29 | +#define TPM_DUMMY_BYTE 0xAA |
| 30 | +#define TPM_WRITE_DIRECTION 0x80 |
| 31 | +#define TPM_BUFSIZE 2048 |
| 32 | + |
| 33 | +struct st33zp24_i2c_phy { |
| 34 | + struct i2c_client *client; |
| 35 | + u8 buf[TPM_BUFSIZE + 1]; |
| 36 | + int io_lpcpd; |
| 37 | +}; |
| 38 | + |
| 39 | +/* |
| 40 | + * write8_reg |
| 41 | + * Send byte to the TIS register according to the ST33ZP24 I2C protocol. |
| 42 | + * @param: tpm_register, the tpm tis register where the data should be written |
| 43 | + * @param: tpm_data, the tpm_data to write inside the tpm_register |
| 44 | + * @param: tpm_size, The length of the data |
| 45 | + * @return: Returns negative errno, or else the number of bytes written. |
| 46 | + */ |
| 47 | +static int write8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size) |
| 48 | +{ |
| 49 | + struct st33zp24_i2c_phy *phy = phy_id; |
| 50 | + |
| 51 | + phy->buf[0] = tpm_register; |
| 52 | + memcpy(phy->buf + 1, tpm_data, tpm_size); |
| 53 | + return i2c_master_send(phy->client, phy->buf, tpm_size + 1); |
| 54 | +} /* write8_reg() */ |
| 55 | + |
| 56 | +/* |
| 57 | + * read8_reg |
| 58 | + * Recv byte from the TIS register according to the ST33ZP24 I2C protocol. |
| 59 | + * @param: tpm_register, the tpm tis register where the data should be read |
| 60 | + * @param: tpm_data, the TPM response |
| 61 | + * @param: tpm_size, tpm TPM response size to read. |
| 62 | + * @return: number of byte read successfully: should be one if success. |
| 63 | + */ |
| 64 | +static int read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size) |
| 65 | +{ |
| 66 | + struct st33zp24_i2c_phy *phy = phy_id; |
| 67 | + u8 status = 0; |
| 68 | + u8 data; |
| 69 | + |
| 70 | + data = TPM_DUMMY_BYTE; |
| 71 | + status = write8_reg(phy, tpm_register, &data, 1); |
| 72 | + if (status == 2) |
| 73 | + status = i2c_master_recv(phy->client, tpm_data, tpm_size); |
| 74 | + return status; |
| 75 | +} /* read8_reg() */ |
| 76 | + |
| 77 | +/* |
| 78 | + * st33zp24_i2c_send |
| 79 | + * Send byte to 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 written |
| 82 | + * @param: tpm_data, the tpm_data to write inside the tpm_register |
| 83 | + * @param: tpm_size, the length of the data |
| 84 | + * @return: number of byte written successfully: should be one if success. |
| 85 | + */ |
| 86 | +static int st33zp24_i2c_send(void *phy_id, u8 tpm_register, u8 *tpm_data, |
| 87 | + int tpm_size) |
| 88 | +{ |
| 89 | + return write8_reg(phy_id, tpm_register | TPM_WRITE_DIRECTION, tpm_data, |
| 90 | + tpm_size); |
| 91 | +} |
| 92 | + |
| 93 | +/* |
| 94 | + * st33zp24_i2c_recv |
| 95 | + * Recv byte from the TIS register according to the ST33ZP24 I2C protocol. |
| 96 | + * @param: phy_id, the phy description |
| 97 | + * @param: tpm_register, the tpm tis register where the data should be read |
| 98 | + * @param: tpm_data, the TPM response |
| 99 | + * @param: tpm_size, tpm TPM response size to read. |
| 100 | + * @return: number of byte read successfully: should be one if success. |
| 101 | + */ |
| 102 | +static int st33zp24_i2c_recv(void *phy_id, u8 tpm_register, u8 *tpm_data, |
| 103 | + int tpm_size) |
| 104 | +{ |
| 105 | + return read8_reg(phy_id, tpm_register, tpm_data, tpm_size); |
| 106 | +} |
| 107 | + |
| 108 | +static const struct st33zp24_phy_ops i2c_phy_ops = { |
| 109 | + .send = st33zp24_i2c_send, |
| 110 | + .recv = st33zp24_i2c_recv, |
| 111 | +}; |
| 112 | + |
| 113 | +#ifdef CONFIG_OF |
| 114 | +static int st33zp24_i2c_of_request_resources(struct st33zp24_i2c_phy *phy) |
| 115 | +{ |
| 116 | + struct device_node *pp; |
| 117 | + struct i2c_client *client = phy->client; |
| 118 | + int gpio; |
| 119 | + int ret; |
| 120 | + |
| 121 | + pp = client->dev.of_node; |
| 122 | + if (!pp) { |
| 123 | + dev_err(&client->dev, "No platform data\n"); |
| 124 | + return -ENODEV; |
| 125 | + } |
| 126 | + |
| 127 | + /* Get GPIO from device tree */ |
| 128 | + gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0); |
| 129 | + if (gpio < 0) { |
| 130 | + dev_err(&client->dev, |
| 131 | + "Failed to retrieve lpcpd-gpios from dts.\n"); |
| 132 | + phy->io_lpcpd = -1; |
| 133 | + /* |
| 134 | + * lpcpd pin is not specified. This is not an issue as |
| 135 | + * power management can be also managed by TPM specific |
| 136 | + * commands. So leave with a success status code. |
| 137 | + */ |
| 138 | + return 0; |
| 139 | + } |
| 140 | + /* GPIO request and configuration */ |
| 141 | + ret = devm_gpio_request_one(&client->dev, gpio, |
| 142 | + GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD"); |
| 143 | + if (ret) { |
| 144 | + dev_err(&client->dev, "Failed to request lpcpd pin\n"); |
| 145 | + return -ENODEV; |
| 146 | + } |
| 147 | + phy->io_lpcpd = gpio; |
| 148 | + |
| 149 | + return 0; |
| 150 | +} |
| 151 | +#else |
| 152 | +static int st33zp24_i2c_of_request_resources(struct st33zp24_i2c_phy *phy) |
| 153 | +{ |
| 154 | + return -ENODEV; |
| 155 | +} |
| 156 | +#endif |
| 157 | + |
| 158 | +static int st33zp24_i2c_request_resources(struct i2c_client *client, |
| 159 | + struct st33zp24_i2c_phy *phy) |
| 160 | +{ |
| 161 | + struct st33zp24_platform_data *pdata; |
| 162 | + int ret; |
| 163 | + |
| 164 | + pdata = client->dev.platform_data; |
| 165 | + if (!pdata) { |
| 166 | + dev_err(&client->dev, "No platform data\n"); |
| 167 | + return -ENODEV; |
| 168 | + } |
| 169 | + |
| 170 | + /* store for late use */ |
| 171 | + phy->io_lpcpd = pdata->io_lpcpd; |
| 172 | + |
| 173 | + if (gpio_is_valid(pdata->io_lpcpd)) { |
| 174 | + ret = devm_gpio_request_one(&client->dev, |
| 175 | + pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH, |
| 176 | + "TPM IO_LPCPD"); |
| 177 | + if (ret) { |
| 178 | + dev_err(&client->dev, "Failed to request lpcpd pin\n"); |
| 179 | + return ret; |
| 180 | + } |
| 181 | + } |
| 182 | + |
| 183 | + return 0; |
| 184 | +} |
| 185 | + |
| 186 | +/* |
| 187 | + * st33zp24_i2c_probe initialize the TPM device |
| 188 | + * @param: client, the i2c_client drescription (TPM I2C description). |
| 189 | + * @param: id, the i2c_device_id struct. |
| 190 | + * @return: 0 in case of success. |
| 191 | + * -1 in other case. |
| 192 | + */ |
| 193 | +static int st33zp24_i2c_probe(struct i2c_client *client, |
| 194 | + const struct i2c_device_id *id) |
| 195 | +{ |
| 196 | + int ret; |
| 197 | + struct st33zp24_platform_data *pdata; |
| 198 | + struct st33zp24_i2c_phy *phy; |
| 199 | + |
| 200 | + if (!client) { |
| 201 | + pr_info("%s: i2c client is NULL. Device not accessible.\n", |
| 202 | + __func__); |
| 203 | + return -ENODEV; |
| 204 | + } |
| 205 | + |
| 206 | + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { |
| 207 | + dev_info(&client->dev, "client not i2c capable\n"); |
| 208 | + return -ENODEV; |
| 209 | + } |
| 210 | + |
| 211 | + phy = devm_kzalloc(&client->dev, sizeof(struct st33zp24_i2c_phy), |
| 212 | + GFP_KERNEL); |
| 213 | + if (!phy) |
| 214 | + return -ENOMEM; |
| 215 | + |
| 216 | + phy->client = client; |
| 217 | + pdata = client->dev.platform_data; |
| 218 | + if (!pdata && client->dev.of_node) { |
| 219 | + ret = st33zp24_i2c_of_request_resources(phy); |
| 220 | + if (ret) |
| 221 | + return ret; |
| 222 | + } else if (pdata) { |
| 223 | + ret = st33zp24_i2c_request_resources(client, phy); |
| 224 | + if (ret) |
| 225 | + return ret; |
| 226 | + } |
| 227 | + |
| 228 | + return st33zp24_probe(phy, &i2c_phy_ops, &client->dev, client->irq, |
| 229 | + phy->io_lpcpd); |
| 230 | +} |
| 231 | + |
| 232 | +/* |
| 233 | + * st33zp24_i2c_remove remove the TPM device |
| 234 | + * @param: client, the i2c_client description (TPM I2C description). |
| 235 | + * @return: 0 in case of success. |
| 236 | + */ |
| 237 | +static int st33zp24_i2c_remove(struct i2c_client *client) |
| 238 | +{ |
| 239 | + struct tpm_chip *chip = i2c_get_clientdata(client); |
| 240 | + |
| 241 | + return st33zp24_remove(chip); |
| 242 | +} |
| 243 | + |
| 244 | +static const struct i2c_device_id st33zp24_i2c_id[] = { |
| 245 | + {TPM_ST33_I2C, 0}, |
| 246 | + {} |
| 247 | +}; |
| 248 | +MODULE_DEVICE_TABLE(i2c, st33zp24_i2c_id); |
| 249 | + |
| 250 | +#ifdef CONFIG_OF |
| 251 | +static const struct of_device_id of_st33zp24_i2c_match[] = { |
| 252 | + { .compatible = "st,st33zp24-i2c", }, |
| 253 | + {} |
| 254 | +}; |
| 255 | +MODULE_DEVICE_TABLE(of, of_st33zp24_i2c_match); |
| 256 | +#endif |
| 257 | + |
| 258 | +static SIMPLE_DEV_PM_OPS(st33zp24_i2c_ops, st33zp24_pm_suspend, |
| 259 | + st33zp24_pm_resume); |
| 260 | + |
| 261 | +static struct i2c_driver st33zp24_i2c_driver = { |
| 262 | + .driver = { |
| 263 | + .owner = THIS_MODULE, |
| 264 | + .name = TPM_ST33_I2C, |
| 265 | + .pm = &st33zp24_i2c_ops, |
| 266 | + .of_match_table = of_match_ptr(of_st33zp24_i2c_match), |
| 267 | + }, |
| 268 | + .probe = st33zp24_i2c_probe, |
| 269 | + .remove = st33zp24_i2c_remove, |
| 270 | + .id_table = st33zp24_i2c_id |
| 271 | +}; |
| 272 | + |
| 273 | +module_i2c_driver(st33zp24_i2c_driver); |
| 274 | + |
| 275 | +MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)"); |
| 276 | +MODULE_DESCRIPTION("STM TPM 1.2 I2C ST33 Driver"); |
| 277 | +MODULE_VERSION("1.3.0"); |
| 278 | +MODULE_LICENSE("GPL"); |
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