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1/* Texas Instruments TMP108 SMBus temperature sensor driver
2 *
3 * Copyright (C) 2016 John Muir <john@jmuir.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/device.h>
18#include <linux/err.h>
19#include <linux/hwmon.h>
20#include <linux/hwmon-sysfs.h>
21#include <linux/module.h>
22#include <linux/mutex.h>
23#include <linux/of.h>
24#include <linux/i2c.h>
25#include <linux/init.h>
26#include <linux/jiffies.h>
27#include <linux/regmap.h>
28#include <linux/slab.h>
29
30#define DRIVER_NAME "tmp108"
31
32#define TMP108_REG_TEMP 0x00
33#define TMP108_REG_CONF 0x01
34#define TMP108_REG_TLOW 0x02
35#define TMP108_REG_THIGH 0x03
36
37#define TMP108_TEMP_MIN_MC -50000 /* Minimum millicelcius. */
38#define TMP108_TEMP_MAX_MC 127937 /* Maximum millicelcius. */
39
40/* Configuration register bits.
41 * Note: these bit definitions are byte swapped.
42 */
43#define TMP108_CONF_M0 0x0100 /* Sensor mode. */
44#define TMP108_CONF_M1 0x0200
45#define TMP108_CONF_TM 0x0400 /* Thermostat mode. */
46#define TMP108_CONF_FL 0x0800 /* Watchdog flag - TLOW */
47#define TMP108_CONF_FH 0x1000 /* Watchdog flag - THIGH */
48#define TMP108_CONF_CR0 0x2000 /* Conversion rate. */
49#define TMP108_CONF_CR1 0x4000
50#define TMP108_CONF_ID 0x8000
51#define TMP108_CONF_HYS0 0x0010 /* Hysteresis. */
52#define TMP108_CONF_HYS1 0x0020
53#define TMP108_CONF_POL 0x0080 /* Polarity of alert. */
54
55/* Defaults set by the hardware upon reset. */
56#define TMP108_CONF_DEFAULTS (TMP108_CONF_CR0 | TMP108_CONF_TM |\
57 TMP108_CONF_HYS0 | TMP108_CONF_M1)
58/* These bits are read-only. */
59#define TMP108_CONF_READ_ONLY (TMP108_CONF_FL | TMP108_CONF_FH |\
60 TMP108_CONF_ID)
61
62#define TMP108_CONF_MODE_MASK (TMP108_CONF_M0|TMP108_CONF_M1)
63#define TMP108_MODE_SHUTDOWN 0x0000
64#define TMP108_MODE_ONE_SHOT TMP108_CONF_M0
65#define TMP108_MODE_CONTINUOUS TMP108_CONF_M1 /* Default */
66 /* When M1 is set, M0 is ignored. */
67
68#define TMP108_CONF_CONVRATE_MASK (TMP108_CONF_CR0|TMP108_CONF_CR1)
69#define TMP108_CONVRATE_0P25HZ 0x0000
70#define TMP108_CONVRATE_1HZ TMP108_CONF_CR0 /* Default */
71#define TMP108_CONVRATE_4HZ TMP108_CONF_CR1
72#define TMP108_CONVRATE_16HZ (TMP108_CONF_CR0|TMP108_CONF_CR1)
73
74#define TMP108_CONF_HYSTERESIS_MASK (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
75#define TMP108_HYSTERESIS_0C 0x0000
76#define TMP108_HYSTERESIS_1C TMP108_CONF_HYS0 /* Default */
77#define TMP108_HYSTERESIS_2C TMP108_CONF_HYS1
78#define TMP108_HYSTERESIS_4C (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
79
80#define TMP108_CONVERSION_TIME_MS 30 /* in milli-seconds */
81
82struct tmp108 {
83 struct regmap *regmap;
84 u16 orig_config;
85 unsigned long ready_time;
86};
87
88/* convert 12-bit TMP108 register value to milliCelsius */
89static inline int tmp108_temp_reg_to_mC(s16 val)
90{
91 return (val & ~0x0f) * 1000 / 256;
92}
93
94/* convert milliCelsius to left adjusted 12-bit TMP108 register value */
95static inline u16 tmp108_mC_to_temp_reg(int val)
96{
97 return (val * 256) / 1000;
98}
99
100static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
101 u32 attr, int channel, long *temp)
102{
103 struct tmp108 *tmp108 = dev_get_drvdata(dev);
104 unsigned int regval;
105 int err, hyst;
106
107 if (type == hwmon_chip) {
108 if (attr == hwmon_chip_update_interval) {
109 err = regmap_read(tmp108->regmap, TMP108_REG_CONF,
110 ®val);
111 if (err < 0)
112 return err;
113 switch (regval & TMP108_CONF_CONVRATE_MASK) {
114 case TMP108_CONVRATE_0P25HZ:
115 default:
116 *temp = 4000;
117 break;
118 case TMP108_CONVRATE_1HZ:
119 *temp = 1000;
120 break;
121 case TMP108_CONVRATE_4HZ:
122 *temp = 250;
123 break;
124 case TMP108_CONVRATE_16HZ:
125 *temp = 63;
126 break;
127 }
128 return 0;
129 }
130 return -EOPNOTSUPP;
131 }
132
133 switch (attr) {
134 case hwmon_temp_input:
135 /* Is it too early to return a conversion ? */
136 if (time_before(jiffies, tmp108->ready_time)) {
137 dev_dbg(dev, "%s: Conversion not ready yet..\n",
138 __func__);
139 return -EAGAIN;
140 }
141 err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, ®val);
142 if (err < 0)
143 return err;
144 *temp = tmp108_temp_reg_to_mC(regval);
145 break;
146 case hwmon_temp_min:
147 case hwmon_temp_max:
148 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min ?
149 TMP108_REG_TLOW : TMP108_REG_THIGH, ®val);
150 if (err < 0)
151 return err;
152 *temp = tmp108_temp_reg_to_mC(regval);
153 break;
154 case hwmon_temp_min_alarm:
155 case hwmon_temp_max_alarm:
156 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val);
157 if (err < 0)
158 return err;
159 *temp = !!(regval & (attr == hwmon_temp_min_alarm ?
160 TMP108_CONF_FL : TMP108_CONF_FH));
161 break;
162 case hwmon_temp_min_hyst:
163 case hwmon_temp_max_hyst:
164 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val);
165 if (err < 0)
166 return err;
167 switch (regval & TMP108_CONF_HYSTERESIS_MASK) {
168 case TMP108_HYSTERESIS_0C:
169 default:
170 hyst = 0;
171 break;
172 case TMP108_HYSTERESIS_1C:
173 hyst = 1000;
174 break;
175 case TMP108_HYSTERESIS_2C:
176 hyst = 2000;
177 break;
178 case TMP108_HYSTERESIS_4C:
179 hyst = 4000;
180 break;
181 }
182 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min_hyst ?
183 TMP108_REG_TLOW : TMP108_REG_THIGH, ®val);
184 if (err < 0)
185 return err;
186 *temp = tmp108_temp_reg_to_mC(regval);
187 if (attr == hwmon_temp_min_hyst)
188 *temp += hyst;
189 else
190 *temp -= hyst;
191 break;
192 default:
193 return -EOPNOTSUPP;
194 }
195
196 return 0;
197}
198
199static int tmp108_write(struct device *dev, enum hwmon_sensor_types type,
200 u32 attr, int channel, long temp)
201{
202 struct tmp108 *tmp108 = dev_get_drvdata(dev);
203 u32 regval, mask;
204 int err;
205
206 if (type == hwmon_chip) {
207 if (attr == hwmon_chip_update_interval) {
208 if (temp < 156)
209 mask = TMP108_CONVRATE_16HZ;
210 else if (temp < 625)
211 mask = TMP108_CONVRATE_4HZ;
212 else if (temp < 2500)
213 mask = TMP108_CONVRATE_1HZ;
214 else
215 mask = TMP108_CONVRATE_0P25HZ;
216 return regmap_update_bits(tmp108->regmap,
217 TMP108_REG_CONF,
218 TMP108_CONF_CONVRATE_MASK,
219 mask);
220 }
221 return -EOPNOTSUPP;
222 }
223
224 switch (attr) {
225 case hwmon_temp_min:
226 case hwmon_temp_max:
227 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
228 return regmap_write(tmp108->regmap,
229 attr == hwmon_temp_min ?
230 TMP108_REG_TLOW : TMP108_REG_THIGH,
231 tmp108_mC_to_temp_reg(temp));
232 case hwmon_temp_min_hyst:
233 case hwmon_temp_max_hyst:
234 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
235 err = regmap_read(tmp108->regmap,
236 attr == hwmon_temp_min_hyst ?
237 TMP108_REG_TLOW : TMP108_REG_THIGH,
238 ®val);
239 if (err < 0)
240 return err;
241 if (attr == hwmon_temp_min_hyst)
242 temp -= tmp108_temp_reg_to_mC(regval);
243 else
244 temp = tmp108_temp_reg_to_mC(regval) - temp;
245 if (temp < 500)
246 mask = TMP108_HYSTERESIS_0C;
247 else if (temp < 1500)
248 mask = TMP108_HYSTERESIS_1C;
249 else if (temp < 3000)
250 mask = TMP108_HYSTERESIS_2C;
251 else
252 mask = TMP108_HYSTERESIS_4C;
253 return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
254 TMP108_CONF_HYSTERESIS_MASK, mask);
255 default:
256 return -EOPNOTSUPP;
257 }
258}
259
260static umode_t tmp108_is_visible(const void *data, enum hwmon_sensor_types type,
261 u32 attr, int channel)
262{
263 if (type == hwmon_chip && attr == hwmon_chip_update_interval)
264 return 0644;
265
266 if (type != hwmon_temp)
267 return 0;
268
269 switch (attr) {
270 case hwmon_temp_input:
271 case hwmon_temp_min_alarm:
272 case hwmon_temp_max_alarm:
273 return 0444;
274 case hwmon_temp_min:
275 case hwmon_temp_max:
276 case hwmon_temp_min_hyst:
277 case hwmon_temp_max_hyst:
278 return 0644;
279 default:
280 return 0;
281 }
282}
283
284static const struct hwmon_channel_info *tmp108_info[] = {
285 HWMON_CHANNEL_INFO(chip,
286 HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
287 HWMON_CHANNEL_INFO(temp,
288 HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
289 HWMON_T_MIN_HYST | HWMON_T_MAX_HYST |
290 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM),
291 NULL
292};
293
294static const struct hwmon_ops tmp108_hwmon_ops = {
295 .is_visible = tmp108_is_visible,
296 .read = tmp108_read,
297 .write = tmp108_write,
298};
299
300static const struct hwmon_chip_info tmp108_chip_info = {
301 .ops = &tmp108_hwmon_ops,
302 .info = tmp108_info,
303};
304
305static void tmp108_restore_config(void *data)
306{
307 struct tmp108 *tmp108 = data;
308
309 regmap_write(tmp108->regmap, TMP108_REG_CONF, tmp108->orig_config);
310}
311
312static bool tmp108_is_writeable_reg(struct device *dev, unsigned int reg)
313{
314 return reg != TMP108_REG_TEMP;
315}
316
317static bool tmp108_is_volatile_reg(struct device *dev, unsigned int reg)
318{
319 /* Configuration register must be volatile to enable FL and FH. */
320 return reg == TMP108_REG_TEMP || reg == TMP108_REG_CONF;
321}
322
323static const struct regmap_config tmp108_regmap_config = {
324 .reg_bits = 8,
325 .val_bits = 16,
326 .max_register = TMP108_REG_THIGH,
327 .writeable_reg = tmp108_is_writeable_reg,
328 .volatile_reg = tmp108_is_volatile_reg,
329 .val_format_endian = REGMAP_ENDIAN_BIG,
330 .cache_type = REGCACHE_RBTREE,
331 .use_single_read = true,
332 .use_single_write = true,
333};
334
335static int tmp108_probe(struct i2c_client *client,
336 const struct i2c_device_id *id)
337{
338 struct device *dev = &client->dev;
339 struct device *hwmon_dev;
340 struct tmp108 *tmp108;
341 int err;
342 u32 config;
343
344 if (!i2c_check_functionality(client->adapter,
345 I2C_FUNC_SMBUS_WORD_DATA)) {
346 dev_err(dev,
347 "adapter doesn't support SMBus word transactions\n");
348 return -ENODEV;
349 }
350
351 tmp108 = devm_kzalloc(dev, sizeof(*tmp108), GFP_KERNEL);
352 if (!tmp108)
353 return -ENOMEM;
354
355 dev_set_drvdata(dev, tmp108);
356
357 tmp108->regmap = devm_regmap_init_i2c(client, &tmp108_regmap_config);
358 if (IS_ERR(tmp108->regmap)) {
359 err = PTR_ERR(tmp108->regmap);
360 dev_err(dev, "regmap init failed: %d", err);
361 return err;
362 }
363
364 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &config);
365 if (err < 0) {
366 dev_err(dev, "error reading config register: %d", err);
367 return err;
368 }
369 tmp108->orig_config = config;
370
371 /* Only continuous mode is supported. */
372 config &= ~TMP108_CONF_MODE_MASK;
373 config |= TMP108_MODE_CONTINUOUS;
374
375 /* Only comparator mode is supported. */
376 config &= ~TMP108_CONF_TM;
377
378 err = regmap_write(tmp108->regmap, TMP108_REG_CONF, config);
379 if (err < 0) {
380 dev_err(dev, "error writing config register: %d", err);
381 return err;
382 }
383
384 tmp108->ready_time = jiffies;
385 if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) ==
386 TMP108_MODE_SHUTDOWN)
387 tmp108->ready_time +=
388 msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
389
390 err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108);
391 if (err) {
392 dev_err(dev, "add action or reset failed: %d", err);
393 return err;
394 }
395
396 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
397 tmp108,
398 &tmp108_chip_info,
399 NULL);
400 return PTR_ERR_OR_ZERO(hwmon_dev);
401}
402
403static int __maybe_unused tmp108_suspend(struct device *dev)
404{
405 struct tmp108 *tmp108 = dev_get_drvdata(dev);
406
407 return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
408 TMP108_CONF_MODE_MASK, TMP108_MODE_SHUTDOWN);
409}
410
411static int __maybe_unused tmp108_resume(struct device *dev)
412{
413 struct tmp108 *tmp108 = dev_get_drvdata(dev);
414 int err;
415
416 err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
417 TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS);
418 tmp108->ready_time = jiffies +
419 msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
420 return err;
421}
422
423static SIMPLE_DEV_PM_OPS(tmp108_dev_pm_ops, tmp108_suspend, tmp108_resume);
424
425static const struct i2c_device_id tmp108_i2c_ids[] = {
426 { "tmp108", 0 },
427 { }
428};
429MODULE_DEVICE_TABLE(i2c, tmp108_i2c_ids);
430
431#ifdef CONFIG_OF
432static const struct of_device_id tmp108_of_ids[] = {
433 { .compatible = "ti,tmp108", },
434 {}
435};
436MODULE_DEVICE_TABLE(of, tmp108_of_ids);
437#endif
438
439static struct i2c_driver tmp108_driver = {
440 .driver = {
441 .name = DRIVER_NAME,
442 .pm = &tmp108_dev_pm_ops,
443 .of_match_table = of_match_ptr(tmp108_of_ids),
444 },
445 .probe = tmp108_probe,
446 .id_table = tmp108_i2c_ids,
447};
448
449module_i2c_driver(tmp108_driver);
450
451MODULE_AUTHOR("John Muir <john@jmuir.com>");
452MODULE_DESCRIPTION("Texas Instruments TMP108 temperature sensor driver");
453MODULE_LICENSE("GPL");