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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Texas Instruments TMP108 SMBus temperature sensor driver
3 *
4 * Copyright (C) 2016 John Muir <john@jmuir.com>
5 */
6
7#include <linux/delay.h>
8#include <linux/device.h>
9#include <linux/err.h>
10#include <linux/hwmon.h>
11#include <linux/hwmon-sysfs.h>
12#include <linux/module.h>
13#include <linux/mutex.h>
14#include <linux/of.h>
15#include <linux/i2c.h>
16#include <linux/init.h>
17#include <linux/jiffies.h>
18#include <linux/regmap.h>
19#include <linux/slab.h>
20
21#define DRIVER_NAME "tmp108"
22
23#define TMP108_REG_TEMP 0x00
24#define TMP108_REG_CONF 0x01
25#define TMP108_REG_TLOW 0x02
26#define TMP108_REG_THIGH 0x03
27
28#define TMP108_TEMP_MIN_MC -50000 /* Minimum millicelcius. */
29#define TMP108_TEMP_MAX_MC 127937 /* Maximum millicelcius. */
30
31/* Configuration register bits.
32 * Note: these bit definitions are byte swapped.
33 */
34#define TMP108_CONF_M0 0x0100 /* Sensor mode. */
35#define TMP108_CONF_M1 0x0200
36#define TMP108_CONF_TM 0x0400 /* Thermostat mode. */
37#define TMP108_CONF_FL 0x0800 /* Watchdog flag - TLOW */
38#define TMP108_CONF_FH 0x1000 /* Watchdog flag - THIGH */
39#define TMP108_CONF_CR0 0x2000 /* Conversion rate. */
40#define TMP108_CONF_CR1 0x4000
41#define TMP108_CONF_ID 0x8000
42#define TMP108_CONF_HYS0 0x0010 /* Hysteresis. */
43#define TMP108_CONF_HYS1 0x0020
44#define TMP108_CONF_POL 0x0080 /* Polarity of alert. */
45
46/* Defaults set by the hardware upon reset. */
47#define TMP108_CONF_DEFAULTS (TMP108_CONF_CR0 | TMP108_CONF_TM |\
48 TMP108_CONF_HYS0 | TMP108_CONF_M1)
49/* These bits are read-only. */
50#define TMP108_CONF_READ_ONLY (TMP108_CONF_FL | TMP108_CONF_FH |\
51 TMP108_CONF_ID)
52
53#define TMP108_CONF_MODE_MASK (TMP108_CONF_M0|TMP108_CONF_M1)
54#define TMP108_MODE_SHUTDOWN 0x0000
55#define TMP108_MODE_ONE_SHOT TMP108_CONF_M0
56#define TMP108_MODE_CONTINUOUS TMP108_CONF_M1 /* Default */
57 /* When M1 is set, M0 is ignored. */
58
59#define TMP108_CONF_CONVRATE_MASK (TMP108_CONF_CR0|TMP108_CONF_CR1)
60#define TMP108_CONVRATE_0P25HZ 0x0000
61#define TMP108_CONVRATE_1HZ TMP108_CONF_CR0 /* Default */
62#define TMP108_CONVRATE_4HZ TMP108_CONF_CR1
63#define TMP108_CONVRATE_16HZ (TMP108_CONF_CR0|TMP108_CONF_CR1)
64
65#define TMP108_CONF_HYSTERESIS_MASK (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
66#define TMP108_HYSTERESIS_0C 0x0000
67#define TMP108_HYSTERESIS_1C TMP108_CONF_HYS0 /* Default */
68#define TMP108_HYSTERESIS_2C TMP108_CONF_HYS1
69#define TMP108_HYSTERESIS_4C (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
70
71#define TMP108_CONVERSION_TIME_MS 30 /* in milli-seconds */
72
73struct tmp108 {
74 struct regmap *regmap;
75 u16 orig_config;
76 unsigned long ready_time;
77};
78
79/* convert 12-bit TMP108 register value to milliCelsius */
80static inline int tmp108_temp_reg_to_mC(s16 val)
81{
82 return (val & ~0x0f) * 1000 / 256;
83}
84
85/* convert milliCelsius to left adjusted 12-bit TMP108 register value */
86static inline u16 tmp108_mC_to_temp_reg(int val)
87{
88 return (val * 256) / 1000;
89}
90
91static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
92 u32 attr, int channel, long *temp)
93{
94 struct tmp108 *tmp108 = dev_get_drvdata(dev);
95 unsigned int regval;
96 int err, hyst;
97
98 if (type == hwmon_chip) {
99 if (attr == hwmon_chip_update_interval) {
100 err = regmap_read(tmp108->regmap, TMP108_REG_CONF,
101 ®val);
102 if (err < 0)
103 return err;
104 switch (regval & TMP108_CONF_CONVRATE_MASK) {
105 case TMP108_CONVRATE_0P25HZ:
106 default:
107 *temp = 4000;
108 break;
109 case TMP108_CONVRATE_1HZ:
110 *temp = 1000;
111 break;
112 case TMP108_CONVRATE_4HZ:
113 *temp = 250;
114 break;
115 case TMP108_CONVRATE_16HZ:
116 *temp = 63;
117 break;
118 }
119 return 0;
120 }
121 return -EOPNOTSUPP;
122 }
123
124 switch (attr) {
125 case hwmon_temp_input:
126 /* Is it too early to return a conversion ? */
127 if (time_before(jiffies, tmp108->ready_time)) {
128 dev_dbg(dev, "%s: Conversion not ready yet..\n",
129 __func__);
130 return -EAGAIN;
131 }
132 err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, ®val);
133 if (err < 0)
134 return err;
135 *temp = tmp108_temp_reg_to_mC(regval);
136 break;
137 case hwmon_temp_min:
138 case hwmon_temp_max:
139 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min ?
140 TMP108_REG_TLOW : TMP108_REG_THIGH, ®val);
141 if (err < 0)
142 return err;
143 *temp = tmp108_temp_reg_to_mC(regval);
144 break;
145 case hwmon_temp_min_alarm:
146 case hwmon_temp_max_alarm:
147 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val);
148 if (err < 0)
149 return err;
150 *temp = !!(regval & (attr == hwmon_temp_min_alarm ?
151 TMP108_CONF_FL : TMP108_CONF_FH));
152 break;
153 case hwmon_temp_min_hyst:
154 case hwmon_temp_max_hyst:
155 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val);
156 if (err < 0)
157 return err;
158 switch (regval & TMP108_CONF_HYSTERESIS_MASK) {
159 case TMP108_HYSTERESIS_0C:
160 default:
161 hyst = 0;
162 break;
163 case TMP108_HYSTERESIS_1C:
164 hyst = 1000;
165 break;
166 case TMP108_HYSTERESIS_2C:
167 hyst = 2000;
168 break;
169 case TMP108_HYSTERESIS_4C:
170 hyst = 4000;
171 break;
172 }
173 err = regmap_read(tmp108->regmap, attr == hwmon_temp_min_hyst ?
174 TMP108_REG_TLOW : TMP108_REG_THIGH, ®val);
175 if (err < 0)
176 return err;
177 *temp = tmp108_temp_reg_to_mC(regval);
178 if (attr == hwmon_temp_min_hyst)
179 *temp += hyst;
180 else
181 *temp -= hyst;
182 break;
183 default:
184 return -EOPNOTSUPP;
185 }
186
187 return 0;
188}
189
190static int tmp108_write(struct device *dev, enum hwmon_sensor_types type,
191 u32 attr, int channel, long temp)
192{
193 struct tmp108 *tmp108 = dev_get_drvdata(dev);
194 u32 regval, mask;
195 int err;
196
197 if (type == hwmon_chip) {
198 if (attr == hwmon_chip_update_interval) {
199 if (temp < 156)
200 mask = TMP108_CONVRATE_16HZ;
201 else if (temp < 625)
202 mask = TMP108_CONVRATE_4HZ;
203 else if (temp < 2500)
204 mask = TMP108_CONVRATE_1HZ;
205 else
206 mask = TMP108_CONVRATE_0P25HZ;
207 return regmap_update_bits(tmp108->regmap,
208 TMP108_REG_CONF,
209 TMP108_CONF_CONVRATE_MASK,
210 mask);
211 }
212 return -EOPNOTSUPP;
213 }
214
215 switch (attr) {
216 case hwmon_temp_min:
217 case hwmon_temp_max:
218 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
219 return regmap_write(tmp108->regmap,
220 attr == hwmon_temp_min ?
221 TMP108_REG_TLOW : TMP108_REG_THIGH,
222 tmp108_mC_to_temp_reg(temp));
223 case hwmon_temp_min_hyst:
224 case hwmon_temp_max_hyst:
225 temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
226 err = regmap_read(tmp108->regmap,
227 attr == hwmon_temp_min_hyst ?
228 TMP108_REG_TLOW : TMP108_REG_THIGH,
229 ®val);
230 if (err < 0)
231 return err;
232 if (attr == hwmon_temp_min_hyst)
233 temp -= tmp108_temp_reg_to_mC(regval);
234 else
235 temp = tmp108_temp_reg_to_mC(regval) - temp;
236 if (temp < 500)
237 mask = TMP108_HYSTERESIS_0C;
238 else if (temp < 1500)
239 mask = TMP108_HYSTERESIS_1C;
240 else if (temp < 3000)
241 mask = TMP108_HYSTERESIS_2C;
242 else
243 mask = TMP108_HYSTERESIS_4C;
244 return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
245 TMP108_CONF_HYSTERESIS_MASK, mask);
246 default:
247 return -EOPNOTSUPP;
248 }
249}
250
251static umode_t tmp108_is_visible(const void *data, enum hwmon_sensor_types type,
252 u32 attr, int channel)
253{
254 if (type == hwmon_chip && attr == hwmon_chip_update_interval)
255 return 0644;
256
257 if (type != hwmon_temp)
258 return 0;
259
260 switch (attr) {
261 case hwmon_temp_input:
262 case hwmon_temp_min_alarm:
263 case hwmon_temp_max_alarm:
264 return 0444;
265 case hwmon_temp_min:
266 case hwmon_temp_max:
267 case hwmon_temp_min_hyst:
268 case hwmon_temp_max_hyst:
269 return 0644;
270 default:
271 return 0;
272 }
273}
274
275static const struct hwmon_channel_info *tmp108_info[] = {
276 HWMON_CHANNEL_INFO(chip,
277 HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
278 HWMON_CHANNEL_INFO(temp,
279 HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
280 HWMON_T_MIN_HYST | HWMON_T_MAX_HYST |
281 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM),
282 NULL
283};
284
285static const struct hwmon_ops tmp108_hwmon_ops = {
286 .is_visible = tmp108_is_visible,
287 .read = tmp108_read,
288 .write = tmp108_write,
289};
290
291static const struct hwmon_chip_info tmp108_chip_info = {
292 .ops = &tmp108_hwmon_ops,
293 .info = tmp108_info,
294};
295
296static void tmp108_restore_config(void *data)
297{
298 struct tmp108 *tmp108 = data;
299
300 regmap_write(tmp108->regmap, TMP108_REG_CONF, tmp108->orig_config);
301}
302
303static bool tmp108_is_writeable_reg(struct device *dev, unsigned int reg)
304{
305 return reg != TMP108_REG_TEMP;
306}
307
308static bool tmp108_is_volatile_reg(struct device *dev, unsigned int reg)
309{
310 /* Configuration register must be volatile to enable FL and FH. */
311 return reg == TMP108_REG_TEMP || reg == TMP108_REG_CONF;
312}
313
314static const struct regmap_config tmp108_regmap_config = {
315 .reg_bits = 8,
316 .val_bits = 16,
317 .max_register = TMP108_REG_THIGH,
318 .writeable_reg = tmp108_is_writeable_reg,
319 .volatile_reg = tmp108_is_volatile_reg,
320 .val_format_endian = REGMAP_ENDIAN_BIG,
321 .cache_type = REGCACHE_RBTREE,
322 .use_single_read = true,
323 .use_single_write = true,
324};
325
326static int tmp108_probe(struct i2c_client *client,
327 const struct i2c_device_id *id)
328{
329 struct device *dev = &client->dev;
330 struct device *hwmon_dev;
331 struct tmp108 *tmp108;
332 int err;
333 u32 config;
334
335 if (!i2c_check_functionality(client->adapter,
336 I2C_FUNC_SMBUS_WORD_DATA)) {
337 dev_err(dev,
338 "adapter doesn't support SMBus word transactions\n");
339 return -ENODEV;
340 }
341
342 tmp108 = devm_kzalloc(dev, sizeof(*tmp108), GFP_KERNEL);
343 if (!tmp108)
344 return -ENOMEM;
345
346 dev_set_drvdata(dev, tmp108);
347
348 tmp108->regmap = devm_regmap_init_i2c(client, &tmp108_regmap_config);
349 if (IS_ERR(tmp108->regmap)) {
350 err = PTR_ERR(tmp108->regmap);
351 dev_err(dev, "regmap init failed: %d", err);
352 return err;
353 }
354
355 err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &config);
356 if (err < 0) {
357 dev_err(dev, "error reading config register: %d", err);
358 return err;
359 }
360 tmp108->orig_config = config;
361
362 /* Only continuous mode is supported. */
363 config &= ~TMP108_CONF_MODE_MASK;
364 config |= TMP108_MODE_CONTINUOUS;
365
366 /* Only comparator mode is supported. */
367 config &= ~TMP108_CONF_TM;
368
369 err = regmap_write(tmp108->regmap, TMP108_REG_CONF, config);
370 if (err < 0) {
371 dev_err(dev, "error writing config register: %d", err);
372 return err;
373 }
374
375 tmp108->ready_time = jiffies;
376 if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) ==
377 TMP108_MODE_SHUTDOWN)
378 tmp108->ready_time +=
379 msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
380
381 err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108);
382 if (err) {
383 dev_err(dev, "add action or reset failed: %d", err);
384 return err;
385 }
386
387 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
388 tmp108,
389 &tmp108_chip_info,
390 NULL);
391 return PTR_ERR_OR_ZERO(hwmon_dev);
392}
393
394static int __maybe_unused tmp108_suspend(struct device *dev)
395{
396 struct tmp108 *tmp108 = dev_get_drvdata(dev);
397
398 return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
399 TMP108_CONF_MODE_MASK, TMP108_MODE_SHUTDOWN);
400}
401
402static int __maybe_unused tmp108_resume(struct device *dev)
403{
404 struct tmp108 *tmp108 = dev_get_drvdata(dev);
405 int err;
406
407 err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
408 TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS);
409 tmp108->ready_time = jiffies +
410 msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
411 return err;
412}
413
414static SIMPLE_DEV_PM_OPS(tmp108_dev_pm_ops, tmp108_suspend, tmp108_resume);
415
416static const struct i2c_device_id tmp108_i2c_ids[] = {
417 { "tmp108", 0 },
418 { }
419};
420MODULE_DEVICE_TABLE(i2c, tmp108_i2c_ids);
421
422#ifdef CONFIG_OF
423static const struct of_device_id tmp108_of_ids[] = {
424 { .compatible = "ti,tmp108", },
425 {}
426};
427MODULE_DEVICE_TABLE(of, tmp108_of_ids);
428#endif
429
430static struct i2c_driver tmp108_driver = {
431 .driver = {
432 .name = DRIVER_NAME,
433 .pm = &tmp108_dev_pm_ops,
434 .of_match_table = of_match_ptr(tmp108_of_ids),
435 },
436 .probe = tmp108_probe,
437 .id_table = tmp108_i2c_ids,
438};
439
440module_i2c_driver(tmp108_driver);
441
442MODULE_AUTHOR("John Muir <john@jmuir.com>");
443MODULE_DESCRIPTION("Texas Instruments TMP108 temperature sensor driver");
444MODULE_LICENSE("GPL");