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 */
write8_reg(void * phy_id,u8 tpm_register,u8 * tpm_data,int tpm_size)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 */
read8_reg(void * phy_id,u8 tpm_register,u8 * tpm_data,int tpm_size)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 */
st33zp24_i2c_send(void * phy_id,u8 tpm_register,u8 * tpm_data,int tpm_size)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 */
st33zp24_i2c_recv(void * phy_id,u8 tpm_register,u8 * tpm_data,int tpm_size)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
st33zp24_i2c_acpi_request_resources(struct i2c_client * client)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
st33zp24_i2c_of_request_resources(struct i2c_client * client)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
st33zp24_i2c_request_resources(struct i2c_client * client)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 */
st33zp24_i2c_probe(struct i2c_client * client,const struct i2c_device_id * id)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 */
st33zp24_i2c_remove(struct i2c_client * client)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
