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