1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * lm92 - Hardware monitoring driver
4 * Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de>
5 *
6 * Based on the lm90 driver, with some ideas taken from the lm_sensors
7 * lm92 driver as well.
8 *
9 * The LM92 is a sensor chip made by National Semiconductor. It reports
10 * its own temperature with a 0.0625 deg resolution and a 0.33 deg
11 * accuracy. Complete datasheet can be obtained from National's website
12 * at:
13 * http://www.national.com/pf/LM/LM92.html
14 *
15 * This driver also supports the MAX6635 sensor chip made by Maxim.
16 * This chip is compatible with the LM92, but has a lesser accuracy
17 * (1.0 deg). Complete datasheet can be obtained from Maxim's website
18 * at:
19 * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
20 *
21 * Since the LM92 was the first chipset supported by this driver, most
22 * comments will refer to this chipset, but are actually general and
23 * concern all supported chipsets, unless mentioned otherwise.
24 *
25 * Support could easily be added for the National Semiconductor LM76
26 * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
27 * with the LM92.
28 */
29
30 #include <linux/err.h>
31 #include <linux/hwmon.h>
32 #include <linux/i2c.h>
33 #include <linux/init.h>
34 #include <linux/module.h>
35 #include <linux/mutex.h>
36 #include <linux/regmap.h>
37 #include <linux/slab.h>
38
39 /*
40 * The LM92 and MAX6635 have 2 two-state pins for address selection,
41 * resulting in 4 possible addresses.
42 */
43 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
44 I2C_CLIENT_END };
45 /* The LM92 registers */
46 #define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
47 #define LM92_REG_TEMP 0x00 /* 16-bit, RO */
48 #define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
49 #define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
50 #define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
51 #define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
52 #define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
53
54 /*
55 * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
56 * left-justified in 16-bit registers. No rounding is done, with such
57 * a resolution it's just not worth it. Note that the MAX6635 doesn't
58 * make use of the 4 lower bits for limits (i.e. effective resolution
59 * for limits is 1 degree Celsius).
60 */
TEMP_FROM_REG(s16 reg)61 static inline int TEMP_FROM_REG(s16 reg)
62 {
63 return reg / 8 * 625 / 10;
64 }
65
TEMP_TO_REG(long val,int resolution)66 static inline s16 TEMP_TO_REG(long val, int resolution)
67 {
68 val = clamp_val(val, -60000, 160000);
69 return DIV_ROUND_CLOSEST(val << (resolution - 9), 1000) << (16 - resolution);
70 }
71
72 /* Alarm flags are stored in the 3 LSB of the temperature register */
ALARMS_FROM_REG(s16 reg)73 static inline u8 ALARMS_FROM_REG(s16 reg)
74 {
75 return reg & 0x0007;
76 }
77
78 /* Client data (each client gets its own) */
79 struct lm92_data {
80 struct regmap *regmap;
81 struct mutex update_lock;
82 int resolution;
83 };
84
lm92_temp_read(struct lm92_data * data,u32 attr,int channel,long * val)85 static int lm92_temp_read(struct lm92_data *data, u32 attr, int channel, long *val)
86 {
87 int reg = -1, hyst_reg = -1, alarm_bit = 0;
88 struct regmap *regmap = data->regmap;
89 u32 temp;
90 int ret;
91
92 switch (attr) {
93 case hwmon_temp_input:
94 reg = LM92_REG_TEMP;
95 break;
96 case hwmon_temp_min:
97 reg = LM92_REG_TEMP_LOW;
98 break;
99 case hwmon_temp_max:
100 reg = LM92_REG_TEMP_HIGH;
101 break;
102 case hwmon_temp_crit:
103 reg = LM92_REG_TEMP_CRIT;
104 break;
105 case hwmon_temp_min_hyst:
106 hyst_reg = LM92_REG_TEMP_LOW;
107 break;
108 case hwmon_temp_max_hyst:
109 hyst_reg = LM92_REG_TEMP_HIGH;
110 break;
111 case hwmon_temp_crit_hyst:
112 hyst_reg = LM92_REG_TEMP_CRIT;
113 break;
114 case hwmon_temp_min_alarm:
115 alarm_bit = 0;
116 break;
117 case hwmon_temp_max_alarm:
118 alarm_bit = 1;
119 break;
120 case hwmon_temp_crit_alarm:
121 alarm_bit = 2;
122 break;
123 default:
124 return -EOPNOTSUPP;
125 }
126 if (reg >= 0) {
127 ret = regmap_read(regmap, reg, &temp);
128 if (ret < 0)
129 return ret;
130 *val = TEMP_FROM_REG(temp);
131 } else if (hyst_reg >= 0) {
132 u32 regs[2] = { hyst_reg, LM92_REG_TEMP_HYST };
133 u16 regvals[2];
134
135 ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
136 if (ret)
137 return ret;
138 if (attr == hwmon_temp_min_hyst)
139 *val = TEMP_FROM_REG(regvals[0]) + TEMP_FROM_REG(regvals[1]);
140 else
141 *val = TEMP_FROM_REG(regvals[0]) - TEMP_FROM_REG(regvals[1]);
142 } else {
143 ret = regmap_read(regmap, LM92_REG_TEMP, &temp);
144 if (ret)
145 return ret;
146 *val = !!(temp & BIT(alarm_bit));
147 }
148 return 0;
149 }
150
lm92_chip_read(struct lm92_data * data,u32 attr,long * val)151 static int lm92_chip_read(struct lm92_data *data, u32 attr, long *val)
152 {
153 u32 temp;
154 int ret;
155
156 switch (attr) {
157 case hwmon_chip_alarms:
158 ret = regmap_read(data->regmap, LM92_REG_TEMP, &temp);
159 if (ret)
160 return ret;
161 *val = ALARMS_FROM_REG(temp);
162 break;
163 default:
164 return -EOPNOTSUPP;
165 }
166 return 0;
167 }
168
lm92_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)169 static int lm92_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
170 int channel, long *val)
171 {
172 struct lm92_data *data = dev_get_drvdata(dev);
173
174 switch (type) {
175 case hwmon_chip:
176 return lm92_chip_read(data, attr, val);
177 case hwmon_temp:
178 return lm92_temp_read(data, attr, channel, val);
179 default:
180 return -EOPNOTSUPP;
181 }
182 }
183
lm92_temp_write(struct lm92_data * data,u32 attr,long val)184 static int lm92_temp_write(struct lm92_data *data, u32 attr, long val)
185 {
186 struct regmap *regmap = data->regmap;
187 int reg, err;
188 u32 temp;
189
190 switch (attr) {
191 case hwmon_temp_min:
192 reg = LM92_REG_TEMP_LOW;
193 break;
194 case hwmon_temp_max:
195 reg = LM92_REG_TEMP_HIGH;
196 break;
197 case hwmon_temp_crit:
198 reg = LM92_REG_TEMP_CRIT;
199 break;
200 case hwmon_temp_crit_hyst:
201 val = clamp_val(val, -120000, 220000);
202 mutex_lock(&data->update_lock);
203 err = regmap_read(regmap, LM92_REG_TEMP_CRIT, &temp);
204 if (err)
205 goto unlock;
206 val = TEMP_TO_REG(TEMP_FROM_REG(temp) - val, data->resolution);
207 err = regmap_write(regmap, LM92_REG_TEMP_HYST, val);
208 unlock:
209 mutex_unlock(&data->update_lock);
210 return err;
211 default:
212 return -EOPNOTSUPP;
213 }
214 return regmap_write(regmap, reg, TEMP_TO_REG(val, data->resolution));
215 }
216
lm92_write(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long val)217 static int lm92_write(struct device *dev, enum hwmon_sensor_types type,
218 u32 attr, int channel, long val)
219 {
220 struct lm92_data *data = dev_get_drvdata(dev);
221
222 switch (type) {
223 case hwmon_temp:
224 return lm92_temp_write(data, attr, val);
225 default:
226 return -EOPNOTSUPP;
227 }
228 }
229
lm92_is_visible(const void * _data,enum hwmon_sensor_types type,u32 attr,int channel)230 static umode_t lm92_is_visible(const void *_data, enum hwmon_sensor_types type,
231 u32 attr, int channel)
232 {
233 switch (type) {
234 case hwmon_chip:
235 switch (attr) {
236 case hwmon_chip_alarms:
237 return 0444;
238 default:
239 break;
240 }
241 break;
242 case hwmon_temp:
243 switch (attr) {
244 case hwmon_temp_min:
245 case hwmon_temp_max:
246 case hwmon_temp_crit:
247 case hwmon_temp_crit_hyst:
248 return 0644;
249 case hwmon_temp_input:
250 case hwmon_temp_min_hyst:
251 case hwmon_temp_max_hyst:
252 case hwmon_temp_min_alarm:
253 case hwmon_temp_max_alarm:
254 case hwmon_temp_crit_alarm:
255 return 0444;
256 default:
257 break;
258 }
259 break;
260 default:
261 break;
262 }
263 return 0;
264 }
265
266 static const struct hwmon_channel_info * const lm92_info[] = {
267 HWMON_CHANNEL_INFO(chip, HWMON_C_ALARMS),
268 HWMON_CHANNEL_INFO(temp,
269 HWMON_T_INPUT |
270 HWMON_T_MIN | HWMON_T_MIN_HYST |
271 HWMON_T_MAX | HWMON_T_MAX_HYST |
272 HWMON_T_CRIT | HWMON_T_CRIT_HYST |
273 HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
274 HWMON_T_CRIT_ALARM),
275 NULL
276 };
277
278 static const struct hwmon_ops lm92_hwmon_ops = {
279 .is_visible = lm92_is_visible,
280 .read = lm92_read,
281 .write = lm92_write,
282 };
283
284 static const struct hwmon_chip_info lm92_chip_info = {
285 .ops = &lm92_hwmon_ops,
286 .info = lm92_info,
287 };
288
289 /*
290 * Detection and registration
291 */
292
lm92_init_client(struct regmap * regmap)293 static int lm92_init_client(struct regmap *regmap)
294 {
295 return regmap_clear_bits(regmap, LM92_REG_CONFIG, 0x01);
296 }
297
298 /* Return 0 if detection is successful, -ENODEV otherwise */
lm92_detect(struct i2c_client * new_client,struct i2c_board_info * info)299 static int lm92_detect(struct i2c_client *new_client,
300 struct i2c_board_info *info)
301 {
302 struct i2c_adapter *adapter = new_client->adapter;
303 u8 config_addr = LM92_REG_CONFIG;
304 u8 man_id_addr = LM92_REG_MAN_ID;
305 int i, regval;
306
307 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
308 | I2C_FUNC_SMBUS_WORD_DATA))
309 return -ENODEV;
310
311 /*
312 * Register values repeat with multiples of 8.
313 * Read twice to improve detection accuracy.
314 */
315 for (i = 0; i < 2; i++) {
316 regval = i2c_smbus_read_word_data(new_client, man_id_addr);
317 if (regval != 0x0180)
318 return -ENODEV;
319 regval = i2c_smbus_read_byte_data(new_client, config_addr);
320 if (regval < 0 || (regval & 0xe0))
321 return -ENODEV;
322 config_addr += 8;
323 man_id_addr += 8;
324 }
325
326 strscpy(info->type, "lm92", I2C_NAME_SIZE);
327
328 return 0;
329 }
330
331 /* regmap */
332
lm92_reg_read(void * context,unsigned int reg,unsigned int * val)333 static int lm92_reg_read(void *context, unsigned int reg, unsigned int *val)
334 {
335 int ret;
336
337 if (reg == LM92_REG_CONFIG)
338 ret = i2c_smbus_read_byte_data(context, reg);
339 else
340 ret = i2c_smbus_read_word_swapped(context, reg);
341 if (ret < 0)
342 return ret;
343
344 *val = ret;
345 return 0;
346 }
347
lm92_reg_write(void * context,unsigned int reg,unsigned int val)348 static int lm92_reg_write(void *context, unsigned int reg, unsigned int val)
349 {
350 if (reg == LM92_REG_CONFIG)
351 return i2c_smbus_write_byte_data(context, LM92_REG_CONFIG, val);
352
353 return i2c_smbus_write_word_swapped(context, reg, val);
354 }
355
lm92_regmap_is_volatile(struct device * dev,unsigned int reg)356 static bool lm92_regmap_is_volatile(struct device *dev, unsigned int reg)
357 {
358 return reg == LM92_REG_TEMP;
359 }
360
lm92_regmap_is_writeable(struct device * dev,unsigned int reg)361 static bool lm92_regmap_is_writeable(struct device *dev, unsigned int reg)
362 {
363 return reg >= LM92_REG_CONFIG;
364 }
365
366 static const struct regmap_config lm92_regmap_config = {
367 .reg_bits = 8,
368 .val_bits = 16,
369 .max_register = LM92_REG_TEMP_HIGH,
370 .cache_type = REGCACHE_MAPLE,
371 .volatile_reg = lm92_regmap_is_volatile,
372 .writeable_reg = lm92_regmap_is_writeable,
373 };
374
375 static const struct regmap_bus lm92_regmap_bus = {
376 .reg_write = lm92_reg_write,
377 .reg_read = lm92_reg_read,
378 };
379
lm92_probe(struct i2c_client * client)380 static int lm92_probe(struct i2c_client *client)
381 {
382 struct device *dev = &client->dev;
383 struct device *hwmon_dev;
384 struct lm92_data *data;
385 struct regmap *regmap;
386 int err;
387
388 regmap = devm_regmap_init(dev, &lm92_regmap_bus, client,
389 &lm92_regmap_config);
390 if (IS_ERR(regmap))
391 return PTR_ERR(regmap);
392
393 data = devm_kzalloc(dev, sizeof(struct lm92_data), GFP_KERNEL);
394 if (!data)
395 return -ENOMEM;
396
397 data->regmap = regmap;
398 data->resolution = (unsigned long)i2c_get_match_data(client);
399 mutex_init(&data->update_lock);
400
401 /* Initialize the chipset */
402 err = lm92_init_client(regmap);
403 if (err)
404 return err;
405
406 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
407 &lm92_chip_info, NULL);
408 return PTR_ERR_OR_ZERO(hwmon_dev);
409 }
410
411 /*
412 * Module and driver stuff
413 */
414
415 /* .driver_data is limit register resolution */
416 static const struct i2c_device_id lm92_id[] = {
417 { "lm92", 13 },
418 { "max6635", 9 },
419 { }
420 };
421 MODULE_DEVICE_TABLE(i2c, lm92_id);
422
423 static struct i2c_driver lm92_driver = {
424 .class = I2C_CLASS_HWMON,
425 .driver = {
426 .name = "lm92",
427 },
428 .probe = lm92_probe,
429 .id_table = lm92_id,
430 .detect = lm92_detect,
431 .address_list = normal_i2c,
432 };
433
434 module_i2c_driver(lm92_driver);
435
436 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
437 MODULE_DESCRIPTION("LM92/MAX6635 driver");
438 MODULE_LICENSE("GPL");
439