xref: /openbmc/linux/drivers/hwmon/tmp102.c (revision a2cce7a9)
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 
53 struct 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 */
64 static 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 */
70 static inline u16 tmp102_mC_to_reg(int val)
71 {
72 	return (val * 128) / 1000;
73 }
74 
75 static const u8 tmp102_reg[] = {
76 	TMP102_TEMP_REG,
77 	TMP102_TLOW_REG,
78 	TMP102_THIGH_REG,
79 };
80 
81 static 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 
101 static int tmp102_read_temp(void *dev, int *temp)
102 {
103 	struct tmp102 *tmp102 = tmp102_update_device(dev);
104 
105 	*temp = tmp102->temp[0];
106 
107 	return 0;
108 }
109 
110 static 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 
120 static 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 
142 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
143 
144 static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
145 			  tmp102_set_temp, 1);
146 
147 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
148 			  tmp102_set_temp, 2);
149 
150 static 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 };
156 ATTRIBUTE_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 
161 static const struct thermal_zone_of_device_ops tmp102_of_thermal_ops = {
162 	.get_temp = tmp102_read_temp,
163 };
164 
165 static 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 
230 fail_restore_config:
231 	i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
232 				     tmp102->config_orig);
233 	return status;
234 }
235 
236 static 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
257 static 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 
270 static 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 
284 static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
285 
286 static const struct i2c_device_id tmp102_id[] = {
287 	{ "tmp102", 0 },
288 	{ }
289 };
290 MODULE_DEVICE_TABLE(i2c, tmp102_id);
291 
292 static 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 
300 module_i2c_driver(tmp102_driver);
301 
302 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
303 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
304 MODULE_LICENSE("GPL");
305