xref: /openbmc/linux/drivers/hwmon/tmp102.c (revision 4f6cce39) 
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 
16 #include <linux/delay.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/i2c.h>
21 #include <linux/hwmon.h>
22 #include <linux/hwmon-sysfs.h>
23 #include <linux/err.h>
24 #include <linux/mutex.h>
25 #include <linux/device.h>
26 #include <linux/jiffies.h>
27 #include <linux/regmap.h>
28 #include <linux/of.h>
29 
30 #define	DRIVER_NAME "tmp102"
31 
32 #define	TMP102_TEMP_REG			0x00
33 #define	TMP102_CONF_REG			0x01
34 /* note: these bit definitions are byte swapped */
35 #define		TMP102_CONF_SD		0x0100
36 #define		TMP102_CONF_TM		0x0200
37 #define		TMP102_CONF_POL		0x0400
38 #define		TMP102_CONF_F0		0x0800
39 #define		TMP102_CONF_F1		0x1000
40 #define		TMP102_CONF_R0		0x2000
41 #define		TMP102_CONF_R1		0x4000
42 #define		TMP102_CONF_OS		0x8000
43 #define		TMP102_CONF_EM		0x0010
44 #define		TMP102_CONF_AL		0x0020
45 #define		TMP102_CONF_CR0		0x0040
46 #define		TMP102_CONF_CR1		0x0080
47 #define	TMP102_TLOW_REG			0x02
48 #define	TMP102_THIGH_REG		0x03
49 
50 #define TMP102_CONFREG_MASK	(TMP102_CONF_SD | TMP102_CONF_TM | \
51 				 TMP102_CONF_POL | TMP102_CONF_F0 | \
52 				 TMP102_CONF_F1 | TMP102_CONF_OS | \
53 				 TMP102_CONF_EM | TMP102_CONF_AL | \
54 				 TMP102_CONF_CR0 | TMP102_CONF_CR1)
55 
56 #define TMP102_CONFIG_CLEAR	(TMP102_CONF_SD | TMP102_CONF_OS | \
57 				 TMP102_CONF_CR0)
58 #define TMP102_CONFIG_SET	(TMP102_CONF_TM | TMP102_CONF_EM | \
59 				 TMP102_CONF_CR1)
60 
61 #define CONVERSION_TIME_MS		35	/* in milli-seconds */
62 
63 struct tmp102 {
64 	struct regmap *regmap;
65 	u16 config_orig;
66 	unsigned long ready_time;
67 };
68 
69 /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
70 static inline int tmp102_reg_to_mC(s16 val)
71 {
72 	return ((val & ~0x01) * 1000) / 128;
73 }
74 
75 /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
76 static inline u16 tmp102_mC_to_reg(int val)
77 {
78 	return (val * 128) / 1000;
79 }
80 
81 static int tmp102_read(struct device *dev, enum hwmon_sensor_types type,
82 		       u32 attr, int channel, long *temp)
83 {
84 	struct tmp102 *tmp102 = dev_get_drvdata(dev);
85 	unsigned int regval;
86 	int err, reg;
87 
88 	switch (attr) {
89 	case hwmon_temp_input:
90 		/* Is it too early to return a conversion ? */
91 		if (time_before(jiffies, tmp102->ready_time)) {
92 			dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
93 			return -EAGAIN;
94 		}
95 		reg = TMP102_TEMP_REG;
96 		break;
97 	case hwmon_temp_max_hyst:
98 		reg = TMP102_TLOW_REG;
99 		break;
100 	case hwmon_temp_max:
101 		reg = TMP102_THIGH_REG;
102 		break;
103 	default:
104 		return -EOPNOTSUPP;
105 	}
106 
107 	err = regmap_read(tmp102->regmap, reg, &regval);
108 	if (err < 0)
109 		return err;
110 	*temp = tmp102_reg_to_mC(regval);
111 
112 	return 0;
113 }
114 
115 static int tmp102_write(struct device *dev, enum hwmon_sensor_types type,
116 			u32 attr, int channel, long temp)
117 {
118 	struct tmp102 *tmp102 = dev_get_drvdata(dev);
119 	int reg;
120 
121 	switch (attr) {
122 	case hwmon_temp_max_hyst:
123 		reg = TMP102_TLOW_REG;
124 		break;
125 	case hwmon_temp_max:
126 		reg = TMP102_THIGH_REG;
127 		break;
128 	default:
129 		return -EOPNOTSUPP;
130 	}
131 
132 	temp = clamp_val(temp, -256000, 255000);
133 	return regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(temp));
134 }
135 
136 static umode_t tmp102_is_visible(const void *data, enum hwmon_sensor_types type,
137 				 u32 attr, int channel)
138 {
139 	if (type != hwmon_temp)
140 		return 0;
141 
142 	switch (attr) {
143 	case hwmon_temp_input:
144 		return S_IRUGO;
145 	case hwmon_temp_max_hyst:
146 	case hwmon_temp_max:
147 		return S_IRUGO | S_IWUSR;
148 	default:
149 		return 0;
150 	}
151 }
152 
153 static u32 tmp102_chip_config[] = {
154 	HWMON_C_REGISTER_TZ,
155 	0
156 };
157 
158 static const struct hwmon_channel_info tmp102_chip = {
159 	.type = hwmon_chip,
160 	.config = tmp102_chip_config,
161 };
162 
163 static u32 tmp102_temp_config[] = {
164 	HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST,
165 	0
166 };
167 
168 static const struct hwmon_channel_info tmp102_temp = {
169 	.type = hwmon_temp,
170 	.config = tmp102_temp_config,
171 };
172 
173 static const struct hwmon_channel_info *tmp102_info[] = {
174 	&tmp102_chip,
175 	&tmp102_temp,
176 	NULL
177 };
178 
179 static const struct hwmon_ops tmp102_hwmon_ops = {
180 	.is_visible = tmp102_is_visible,
181 	.read = tmp102_read,
182 	.write = tmp102_write,
183 };
184 
185 static const struct hwmon_chip_info tmp102_chip_info = {
186 	.ops = &tmp102_hwmon_ops,
187 	.info = tmp102_info,
188 };
189 
190 static void tmp102_restore_config(void *data)
191 {
192 	struct tmp102 *tmp102 = data;
193 
194 	regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
195 }
196 
197 static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
198 {
199 	return reg != TMP102_TEMP_REG;
200 }
201 
202 static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
203 {
204 	return reg == TMP102_TEMP_REG;
205 }
206 
207 static const struct regmap_config tmp102_regmap_config = {
208 	.reg_bits = 8,
209 	.val_bits = 16,
210 	.max_register = TMP102_THIGH_REG,
211 	.writeable_reg = tmp102_is_writeable_reg,
212 	.volatile_reg = tmp102_is_volatile_reg,
213 	.val_format_endian = REGMAP_ENDIAN_BIG,
214 	.cache_type = REGCACHE_RBTREE,
215 	.use_single_rw = true,
216 };
217 
218 static int tmp102_probe(struct i2c_client *client,
219 			const struct i2c_device_id *id)
220 {
221 	struct device *dev = &client->dev;
222 	struct device *hwmon_dev;
223 	struct tmp102 *tmp102;
224 	unsigned int regval;
225 	int err;
226 
227 	if (!i2c_check_functionality(client->adapter,
228 				     I2C_FUNC_SMBUS_WORD_DATA)) {
229 		dev_err(dev,
230 			"adapter doesn't support SMBus word transactions\n");
231 		return -ENODEV;
232 	}
233 
234 	tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
235 	if (!tmp102)
236 		return -ENOMEM;
237 
238 	i2c_set_clientdata(client, tmp102);
239 
240 	tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
241 	if (IS_ERR(tmp102->regmap))
242 		return PTR_ERR(tmp102->regmap);
243 
244 	err = regmap_read(tmp102->regmap, TMP102_CONF_REG, &regval);
245 	if (err < 0) {
246 		dev_err(dev, "error reading config register\n");
247 		return err;
248 	}
249 
250 	if ((regval & ~TMP102_CONFREG_MASK) !=
251 	    (TMP102_CONF_R0 | TMP102_CONF_R1)) {
252 		dev_err(dev, "unexpected config register value\n");
253 		return -ENODEV;
254 	}
255 
256 	tmp102->config_orig = regval;
257 
258 	err = devm_add_action_or_reset(dev, tmp102_restore_config, tmp102);
259 	if (err)
260 		return err;
261 
262 	regval &= ~TMP102_CONFIG_CLEAR;
263 	regval |= TMP102_CONFIG_SET;
264 
265 	err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
266 	if (err < 0) {
267 		dev_err(dev, "error writing config register\n");
268 		return err;
269 	}
270 
271 	tmp102->ready_time = jiffies;
272 	if (tmp102->config_orig & TMP102_CONF_SD) {
273 		/*
274 		 * Mark that we are not ready with data until the first
275 		 * conversion is complete
276 		 */
277 		tmp102->ready_time += msecs_to_jiffies(CONVERSION_TIME_MS);
278 	}
279 
280 	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
281 							 tmp102,
282 							 &tmp102_chip_info,
283 							 NULL);
284 	if (IS_ERR(hwmon_dev)) {
285 		dev_dbg(dev, "unable to register hwmon device\n");
286 		return PTR_ERR(hwmon_dev);
287 	}
288 	dev_info(dev, "initialized\n");
289 
290 	return 0;
291 }
292 
293 #ifdef CONFIG_PM_SLEEP
294 static int tmp102_suspend(struct device *dev)
295 {
296 	struct i2c_client *client = to_i2c_client(dev);
297 	struct tmp102 *tmp102 = i2c_get_clientdata(client);
298 
299 	return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
300 				  TMP102_CONF_SD, TMP102_CONF_SD);
301 }
302 
303 static int tmp102_resume(struct device *dev)
304 {
305 	struct i2c_client *client = to_i2c_client(dev);
306 	struct tmp102 *tmp102 = i2c_get_clientdata(client);
307 	int err;
308 
309 	err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
310 				 TMP102_CONF_SD, 0);
311 
312 	tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
313 
314 	return err;
315 }
316 #endif /* CONFIG_PM */
317 
318 static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
319 
320 static const struct i2c_device_id tmp102_id[] = {
321 	{ "tmp102", 0 },
322 	{ }
323 };
324 MODULE_DEVICE_TABLE(i2c, tmp102_id);
325 
326 static struct i2c_driver tmp102_driver = {
327 	.driver.name	= DRIVER_NAME,
328 	.driver.pm	= &tmp102_dev_pm_ops,
329 	.probe		= tmp102_probe,
330 	.id_table	= tmp102_id,
331 };
332 
333 module_i2c_driver(tmp102_driver);
334 
335 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
336 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
337 MODULE_LICENSE("GPL");
338