1/* Texas Instruments TMP102 SMBus temperature sensor driver
2 *
3 * Copyright (C) 2010 Steven King <sfking@fdwdc.com>
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, write to the Free Software
17 * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20#include <linux/module.h>
21#include <linux/init.h>
22#include <linux/slab.h>
23#include <linux/i2c.h>
24#include <linux/hwmon.h>
25#include <linux/hwmon-sysfs.h>
26#include <linux/err.h>
27#include <linux/mutex.h>
28#include <linux/device.h>
29#include <linux/jiffies.h>
30#include <linux/thermal.h>
31#include <linux/of.h>
32
33#define	DRIVER_NAME "tmp102"
34
35#define	TMP102_TEMP_REG			0x00
36#define	TMP102_CONF_REG			0x01
37/* note: these bit definitions are byte swapped */
38#define		TMP102_CONF_SD		0x0100
39#define		TMP102_CONF_TM		0x0200
40#define		TMP102_CONF_POL		0x0400
41#define		TMP102_CONF_F0		0x0800
42#define		TMP102_CONF_F1		0x1000
43#define		TMP102_CONF_R0		0x2000
44#define		TMP102_CONF_R1		0x4000
45#define		TMP102_CONF_OS		0x8000
46#define		TMP102_CONF_EM		0x0010
47#define		TMP102_CONF_AL		0x0020
48#define		TMP102_CONF_CR0		0x0040
49#define		TMP102_CONF_CR1		0x0080
50#define	TMP102_TLOW_REG			0x02
51#define	TMP102_THIGH_REG		0x03
52
53struct tmp102 {
54	struct i2c_client *client;
55	struct device *hwmon_dev;
56	struct thermal_zone_device *tz;
57	struct mutex lock;
58	u16 config_orig;
59	unsigned long last_update;
60	int temp[3];
61};
62
63/* convert left adjusted 13-bit TMP102 register value to milliCelsius */
64static inline int tmp102_reg_to_mC(s16 val)
65{
66	return ((val & ~0x01) * 1000) / 128;
67}
68
69/* convert milliCelsius to left adjusted 13-bit TMP102 register value */
70static inline u16 tmp102_mC_to_reg(int val)
71{
72	return (val * 128) / 1000;
73}
74
75static const u8 tmp102_reg[] = {
76	TMP102_TEMP_REG,
77	TMP102_TLOW_REG,
78	TMP102_THIGH_REG,
79};
80
81static struct tmp102 *tmp102_update_device(struct device *dev)
82{
83	struct tmp102 *tmp102 = dev_get_drvdata(dev);
84	struct i2c_client *client = tmp102->client;
85
86	mutex_lock(&tmp102->lock);
87	if (time_after(jiffies, tmp102->last_update + HZ / 3)) {
88		int i;
89		for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
90			int status = i2c_smbus_read_word_swapped(client,
91								 tmp102_reg[i]);
92			if (status > -1)
93				tmp102->temp[i] = tmp102_reg_to_mC(status);
94		}
95		tmp102->last_update = jiffies;
96	}
97	mutex_unlock(&tmp102->lock);
98	return tmp102;
99}
100
101static int tmp102_read_temp(void *dev, long *temp)
102{
103	struct tmp102 *tmp102 = tmp102_update_device(dev);
104
105	*temp = tmp102->temp[0];
106
107	return 0;
108}
109
110static ssize_t tmp102_show_temp(struct device *dev,
111				struct device_attribute *attr,
112				char *buf)
113{
114	struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
115	struct tmp102 *tmp102 = tmp102_update_device(dev);
116
117	return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
118}
119
120static ssize_t tmp102_set_temp(struct device *dev,
121			       struct device_attribute *attr,
122			       const char *buf, size_t count)
123{
124	struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
125	struct tmp102 *tmp102 = dev_get_drvdata(dev);
126	struct i2c_client *client = tmp102->client;
127	long val;
128	int status;
129
130	if (kstrtol(buf, 10, &val) < 0)
131		return -EINVAL;
132	val = clamp_val(val, -256000, 255000);
133
134	mutex_lock(&tmp102->lock);
135	tmp102->temp[sda->index] = val;
136	status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
137					      tmp102_mC_to_reg(val));
138	mutex_unlock(&tmp102->lock);
139	return status ? : count;
140}
141
142static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
143
144static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
145			  tmp102_set_temp, 1);
146
147static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
148			  tmp102_set_temp, 2);
149
150static struct attribute *tmp102_attrs[] = {
151	&sensor_dev_attr_temp1_input.dev_attr.attr,
152	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
153	&sensor_dev_attr_temp1_max.dev_attr.attr,
154	NULL
155};
156ATTRIBUTE_GROUPS(tmp102);
157
158#define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
159#define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)
160
161static const struct thermal_zone_of_device_ops tmp102_of_thermal_ops = {
162	.get_temp = tmp102_read_temp,
163};
164
165static int tmp102_probe(struct i2c_client *client,
166				  const struct i2c_device_id *id)
167{
168	struct device *dev = &client->dev;
169	struct device *hwmon_dev;
170	struct tmp102 *tmp102;
171	int status;
172
173	if (!i2c_check_functionality(client->adapter,
174				     I2C_FUNC_SMBUS_WORD_DATA)) {
175		dev_err(dev,
176			"adapter doesn't support SMBus word transactions\n");
177		return -ENODEV;
178	}
179
180	tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
181	if (!tmp102)
182		return -ENOMEM;
183
184	i2c_set_clientdata(client, tmp102);
185	tmp102->client = client;
186
187	status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
188	if (status < 0) {
189		dev_err(dev, "error reading config register\n");
190		return status;
191	}
192	tmp102->config_orig = status;
193	status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
194					      TMP102_CONFIG);
195	if (status < 0) {
196		dev_err(dev, "error writing config register\n");
197		goto fail_restore_config;
198	}
199	status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
200	if (status < 0) {
201		dev_err(dev, "error reading config register\n");
202		goto fail_restore_config;
203	}
204	status &= ~TMP102_CONFIG_RD_ONLY;
205	if (status != TMP102_CONFIG) {
206		dev_err(dev, "config settings did not stick\n");
207		status = -ENODEV;
208		goto fail_restore_config;
209	}
210	tmp102->last_update = jiffies - HZ;
211	mutex_init(&tmp102->lock);
212
213	hwmon_dev = hwmon_device_register_with_groups(dev, client->name,
214						      tmp102, tmp102_groups);
215	if (IS_ERR(hwmon_dev)) {
216		dev_dbg(dev, "unable to register hwmon device\n");
217		status = PTR_ERR(hwmon_dev);
218		goto fail_restore_config;
219	}
220	tmp102->hwmon_dev = hwmon_dev;
221	tmp102->tz = thermal_zone_of_sensor_register(hwmon_dev, 0, hwmon_dev,
222						     &tmp102_of_thermal_ops);
223	if (IS_ERR(tmp102->tz))
224		tmp102->tz = NULL;
225
226	dev_info(dev, "initialized\n");
227
228	return 0;
229
230fail_restore_config:
231	i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
232				     tmp102->config_orig);
233	return status;
234}
235
236static int tmp102_remove(struct i2c_client *client)
237{
238	struct tmp102 *tmp102 = i2c_get_clientdata(client);
239
240	thermal_zone_of_sensor_unregister(tmp102->hwmon_dev, tmp102->tz);
241	hwmon_device_unregister(tmp102->hwmon_dev);
242
243	/* Stop monitoring if device was stopped originally */
244	if (tmp102->config_orig & TMP102_CONF_SD) {
245		int config;
246
247		config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
248		if (config >= 0)
249			i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
250						     config | TMP102_CONF_SD);
251	}
252
253	return 0;
254}
255
256#ifdef CONFIG_PM_SLEEP
257static int tmp102_suspend(struct device *dev)
258{
259	struct i2c_client *client = to_i2c_client(dev);
260	int config;
261
262	config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
263	if (config < 0)
264		return config;
265
266	config |= TMP102_CONF_SD;
267	return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
268}
269
270static int tmp102_resume(struct device *dev)
271{
272	struct i2c_client *client = to_i2c_client(dev);
273	int config;
274
275	config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);
276	if (config < 0)
277		return config;
278
279	config &= ~TMP102_CONF_SD;
280	return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);
281}
282#endif /* CONFIG_PM */
283
284static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
285
286static const struct i2c_device_id tmp102_id[] = {
287	{ "tmp102", 0 },
288	{ }
289};
290MODULE_DEVICE_TABLE(i2c, tmp102_id);
291
292static struct i2c_driver tmp102_driver = {
293	.driver.name	= DRIVER_NAME,
294	.driver.pm	= &tmp102_dev_pm_ops,
295	.probe		= tmp102_probe,
296	.remove		= tmp102_remove,
297	.id_table	= tmp102_id,
298};
299
300module_i2c_driver(tmp102_driver);
301
302MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
303MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
304MODULE_LICENSE("GPL");
305