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d21ed22b GR |
1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* | |
3 | * Driver for MAX31730 3-Channel Remote Temperature Sensor | |
4 | * | |
5 | * Copyright (c) 2019 Guenter Roeck <linux@roeck-us.net> | |
6 | */ | |
7 | ||
8 | #include <linux/bits.h> | |
9 | #include <linux/err.h> | |
10 | #include <linux/i2c.h> | |
11 | #include <linux/init.h> | |
12 | #include <linux/hwmon.h> | |
13 | #include <linux/module.h> | |
d21ed22b GR |
14 | #include <linux/of.h> |
15 | #include <linux/slab.h> | |
16 | ||
17 | /* Addresses scanned */ | |
18 | static const unsigned short normal_i2c[] = { 0x1c, 0x1d, 0x1e, 0x1f, 0x4c, | |
19 | 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; | |
20 | ||
21 | /* The MAX31730 registers */ | |
22 | #define MAX31730_REG_TEMP 0x00 | |
23 | #define MAX31730_REG_CONF 0x13 | |
24 | #define MAX31730_STOP BIT(7) | |
25 | #define MAX31730_EXTRANGE BIT(1) | |
26 | #define MAX31730_REG_TEMP_OFFSET 0x16 | |
27 | #define MAX31730_TEMP_OFFSET_BASELINE 0x77 | |
28 | #define MAX31730_REG_OFFSET_ENABLE 0x17 | |
29 | #define MAX31730_REG_TEMP_MAX 0x20 | |
30 | #define MAX31730_REG_TEMP_MIN 0x30 | |
31 | #define MAX31730_REG_STATUS_HIGH 0x32 | |
32 | #define MAX31730_REG_STATUS_LOW 0x33 | |
33 | #define MAX31730_REG_CHANNEL_ENABLE 0x35 | |
34 | #define MAX31730_REG_TEMP_FAULT 0x36 | |
35 | ||
36 | #define MAX31730_REG_MFG_ID 0x50 | |
37 | #define MAX31730_MFG_ID 0x4d | |
38 | #define MAX31730_REG_MFG_REV 0x51 | |
39 | #define MAX31730_MFG_REV 0x01 | |
40 | ||
41 | #define MAX31730_TEMP_MIN (-128000) | |
42 | #define MAX31730_TEMP_MAX 127937 | |
43 | ||
44 | /* Each client has this additional data */ | |
45 | struct max31730_data { | |
46 | struct i2c_client *client; | |
47 | u8 orig_conf; | |
48 | u8 current_conf; | |
49 | u8 offset_enable; | |
50 | u8 channel_enable; | |
51 | }; | |
52 | ||
53 | /*-----------------------------------------------------------------------*/ | |
54 | ||
55 | static inline long max31730_reg_to_mc(s16 temp) | |
56 | { | |
57 | return DIV_ROUND_CLOSEST((temp >> 4) * 1000, 16); | |
58 | } | |
59 | ||
60 | static int max31730_write_config(struct max31730_data *data, u8 set_mask, | |
61 | u8 clr_mask) | |
62 | { | |
63 | u8 value; | |
64 | ||
65 | clr_mask |= MAX31730_EXTRANGE; | |
66 | value = data->current_conf & ~clr_mask; | |
67 | value |= set_mask; | |
68 | ||
69 | if (data->current_conf != value) { | |
70 | s32 err; | |
71 | ||
72 | err = i2c_smbus_write_byte_data(data->client, MAX31730_REG_CONF, | |
73 | value); | |
74 | if (err) | |
75 | return err; | |
76 | data->current_conf = value; | |
77 | } | |
78 | return 0; | |
79 | } | |
80 | ||
81 | static int max31730_set_enable(struct i2c_client *client, int reg, | |
82 | u8 *confdata, int channel, bool enable) | |
83 | { | |
84 | u8 regval = *confdata; | |
85 | int err; | |
86 | ||
87 | if (enable) | |
88 | regval |= BIT(channel); | |
89 | else | |
90 | regval &= ~BIT(channel); | |
91 | ||
92 | if (regval != *confdata) { | |
93 | err = i2c_smbus_write_byte_data(client, reg, regval); | |
94 | if (err) | |
95 | return err; | |
96 | *confdata = regval; | |
97 | } | |
98 | return 0; | |
99 | } | |
100 | ||
101 | static int max31730_set_offset_enable(struct max31730_data *data, int channel, | |
102 | bool enable) | |
103 | { | |
104 | return max31730_set_enable(data->client, MAX31730_REG_OFFSET_ENABLE, | |
105 | &data->offset_enable, channel, enable); | |
106 | } | |
107 | ||
108 | static int max31730_set_channel_enable(struct max31730_data *data, int channel, | |
109 | bool enable) | |
110 | { | |
111 | return max31730_set_enable(data->client, MAX31730_REG_CHANNEL_ENABLE, | |
112 | &data->channel_enable, channel, enable); | |
113 | } | |
114 | ||
115 | static int max31730_read(struct device *dev, enum hwmon_sensor_types type, | |
116 | u32 attr, int channel, long *val) | |
117 | { | |
118 | struct max31730_data *data = dev_get_drvdata(dev); | |
119 | int regval, reg, offset; | |
120 | ||
121 | if (type != hwmon_temp) | |
122 | return -EINVAL; | |
123 | ||
124 | switch (attr) { | |
125 | case hwmon_temp_input: | |
126 | if (!(data->channel_enable & BIT(channel))) | |
127 | return -ENODATA; | |
128 | reg = MAX31730_REG_TEMP + (channel * 2); | |
129 | break; | |
130 | case hwmon_temp_max: | |
131 | reg = MAX31730_REG_TEMP_MAX + (channel * 2); | |
132 | break; | |
133 | case hwmon_temp_min: | |
134 | reg = MAX31730_REG_TEMP_MIN; | |
135 | break; | |
136 | case hwmon_temp_enable: | |
137 | *val = !!(data->channel_enable & BIT(channel)); | |
138 | return 0; | |
139 | case hwmon_temp_offset: | |
140 | if (!channel) | |
141 | return -EINVAL; | |
142 | if (!(data->offset_enable & BIT(channel))) { | |
143 | *val = 0; | |
144 | return 0; | |
145 | } | |
146 | offset = i2c_smbus_read_byte_data(data->client, | |
147 | MAX31730_REG_TEMP_OFFSET); | |
148 | if (offset < 0) | |
149 | return offset; | |
150 | *val = (offset - MAX31730_TEMP_OFFSET_BASELINE) * 125; | |
151 | return 0; | |
152 | case hwmon_temp_fault: | |
153 | regval = i2c_smbus_read_byte_data(data->client, | |
154 | MAX31730_REG_TEMP_FAULT); | |
155 | if (regval < 0) | |
156 | return regval; | |
157 | *val = !!(regval & BIT(channel)); | |
158 | return 0; | |
159 | case hwmon_temp_min_alarm: | |
160 | regval = i2c_smbus_read_byte_data(data->client, | |
161 | MAX31730_REG_STATUS_LOW); | |
162 | if (regval < 0) | |
163 | return regval; | |
164 | *val = !!(regval & BIT(channel)); | |
165 | return 0; | |
166 | case hwmon_temp_max_alarm: | |
167 | regval = i2c_smbus_read_byte_data(data->client, | |
168 | MAX31730_REG_STATUS_HIGH); | |
169 | if (regval < 0) | |
170 | return regval; | |
171 | *val = !!(regval & BIT(channel)); | |
172 | return 0; | |
173 | default: | |
174 | return -EINVAL; | |
175 | } | |
176 | regval = i2c_smbus_read_word_swapped(data->client, reg); | |
177 | if (regval < 0) | |
178 | return regval; | |
179 | ||
180 | *val = max31730_reg_to_mc(regval); | |
181 | ||
182 | return 0; | |
183 | } | |
184 | ||
185 | static int max31730_write(struct device *dev, enum hwmon_sensor_types type, | |
186 | u32 attr, int channel, long val) | |
187 | { | |
188 | struct max31730_data *data = dev_get_drvdata(dev); | |
189 | int reg, err; | |
190 | ||
191 | if (type != hwmon_temp) | |
192 | return -EINVAL; | |
193 | ||
194 | switch (attr) { | |
195 | case hwmon_temp_max: | |
196 | reg = MAX31730_REG_TEMP_MAX + channel * 2; | |
197 | break; | |
198 | case hwmon_temp_min: | |
199 | reg = MAX31730_REG_TEMP_MIN; | |
200 | break; | |
201 | case hwmon_temp_enable: | |
202 | if (val != 0 && val != 1) | |
203 | return -EINVAL; | |
204 | return max31730_set_channel_enable(data, channel, val); | |
205 | case hwmon_temp_offset: | |
206 | val = clamp_val(val, -14875, 17000) + 14875; | |
207 | val = DIV_ROUND_CLOSEST(val, 125); | |
208 | err = max31730_set_offset_enable(data, channel, | |
209 | val != MAX31730_TEMP_OFFSET_BASELINE); | |
210 | if (err) | |
211 | return err; | |
212 | return i2c_smbus_write_byte_data(data->client, | |
213 | MAX31730_REG_TEMP_OFFSET, val); | |
214 | default: | |
215 | return -EINVAL; | |
216 | } | |
217 | ||
218 | val = clamp_val(val, MAX31730_TEMP_MIN, MAX31730_TEMP_MAX); | |
219 | val = DIV_ROUND_CLOSEST(val << 4, 1000) << 4; | |
220 | ||
221 | return i2c_smbus_write_word_swapped(data->client, reg, (u16)val); | |
222 | } | |
223 | ||
224 | static umode_t max31730_is_visible(const void *data, | |
225 | enum hwmon_sensor_types type, | |
226 | u32 attr, int channel) | |
227 | { | |
228 | switch (type) { | |
229 | case hwmon_temp: | |
230 | switch (attr) { | |
231 | case hwmon_temp_input: | |
232 | case hwmon_temp_min_alarm: | |
233 | case hwmon_temp_max_alarm: | |
234 | case hwmon_temp_fault: | |
235 | return 0444; | |
236 | case hwmon_temp_min: | |
237 | return channel ? 0444 : 0644; | |
238 | case hwmon_temp_offset: | |
239 | case hwmon_temp_enable: | |
240 | case hwmon_temp_max: | |
241 | return 0644; | |
242 | } | |
243 | break; | |
244 | default: | |
245 | break; | |
246 | } | |
247 | return 0; | |
248 | } | |
249 | ||
c70164ad | 250 | static const struct hwmon_channel_info * const max31730_info[] = { |
d21ed22b GR |
251 | HWMON_CHANNEL_INFO(chip, |
252 | HWMON_C_REGISTER_TZ), | |
253 | HWMON_CHANNEL_INFO(temp, | |
254 | HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX | | |
255 | HWMON_T_ENABLE | | |
256 | HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM, | |
257 | HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX | | |
258 | HWMON_T_OFFSET | HWMON_T_ENABLE | | |
259 | HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM | | |
260 | HWMON_T_FAULT, | |
261 | HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX | | |
262 | HWMON_T_OFFSET | HWMON_T_ENABLE | | |
263 | HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM | | |
264 | HWMON_T_FAULT, | |
265 | HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX | | |
266 | HWMON_T_OFFSET | HWMON_T_ENABLE | | |
267 | HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM | | |
268 | HWMON_T_FAULT | |
269 | ), | |
270 | NULL | |
271 | }; | |
272 | ||
273 | static const struct hwmon_ops max31730_hwmon_ops = { | |
274 | .is_visible = max31730_is_visible, | |
275 | .read = max31730_read, | |
276 | .write = max31730_write, | |
277 | }; | |
278 | ||
279 | static const struct hwmon_chip_info max31730_chip_info = { | |
280 | .ops = &max31730_hwmon_ops, | |
281 | .info = max31730_info, | |
282 | }; | |
283 | ||
284 | static void max31730_remove(void *data) | |
285 | { | |
286 | struct max31730_data *max31730 = data; | |
287 | struct i2c_client *client = max31730->client; | |
288 | ||
289 | i2c_smbus_write_byte_data(client, MAX31730_REG_CONF, | |
290 | max31730->orig_conf); | |
291 | } | |
292 | ||
293 | static int | |
67487038 | 294 | max31730_probe(struct i2c_client *client) |
d21ed22b GR |
295 | { |
296 | struct device *dev = &client->dev; | |
297 | struct device *hwmon_dev; | |
298 | struct max31730_data *data; | |
299 | int status, err; | |
300 | ||
301 | if (!i2c_check_functionality(client->adapter, | |
302 | I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) | |
303 | return -EIO; | |
304 | ||
305 | data = devm_kzalloc(dev, sizeof(struct max31730_data), GFP_KERNEL); | |
306 | if (!data) | |
307 | return -ENOMEM; | |
308 | ||
309 | data->client = client; | |
310 | ||
311 | /* Cache original configuration and enable status */ | |
312 | status = i2c_smbus_read_byte_data(client, MAX31730_REG_CHANNEL_ENABLE); | |
313 | if (status < 0) | |
314 | return status; | |
315 | data->channel_enable = status; | |
316 | ||
317 | status = i2c_smbus_read_byte_data(client, MAX31730_REG_OFFSET_ENABLE); | |
318 | if (status < 0) | |
319 | return status; | |
320 | data->offset_enable = status; | |
321 | ||
322 | status = i2c_smbus_read_byte_data(client, MAX31730_REG_CONF); | |
323 | if (status < 0) | |
324 | return status; | |
325 | data->orig_conf = status; | |
326 | data->current_conf = status; | |
327 | ||
328 | err = max31730_write_config(data, | |
329 | data->channel_enable ? 0 : MAX31730_STOP, | |
330 | data->channel_enable ? MAX31730_STOP : 0); | |
331 | if (err) | |
332 | return err; | |
333 | ||
334 | dev_set_drvdata(dev, data); | |
335 | ||
336 | err = devm_add_action_or_reset(dev, max31730_remove, data); | |
337 | if (err) | |
338 | return err; | |
339 | ||
340 | hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, | |
341 | data, | |
342 | &max31730_chip_info, | |
343 | NULL); | |
344 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
345 | } | |
346 | ||
347 | static const struct i2c_device_id max31730_ids[] = { | |
348 | { "max31730", 0, }, | |
349 | { } | |
350 | }; | |
351 | MODULE_DEVICE_TABLE(i2c, max31730_ids); | |
352 | ||
353 | static const struct of_device_id __maybe_unused max31730_of_match[] = { | |
354 | { | |
355 | .compatible = "maxim,max31730", | |
356 | }, | |
357 | { }, | |
358 | }; | |
359 | MODULE_DEVICE_TABLE(of, max31730_of_match); | |
360 | ||
361 | static bool max31730_check_reg_temp(struct i2c_client *client, | |
362 | int reg) | |
363 | { | |
364 | int regval; | |
365 | ||
366 | regval = i2c_smbus_read_byte_data(client, reg + 1); | |
367 | return regval < 0 || (regval & 0x0f); | |
368 | } | |
369 | ||
370 | /* Return 0 if detection is successful, -ENODEV otherwise */ | |
371 | static int max31730_detect(struct i2c_client *client, | |
372 | struct i2c_board_info *info) | |
373 | { | |
374 | struct i2c_adapter *adapter = client->adapter; | |
375 | int regval; | |
376 | int i; | |
377 | ||
378 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | | |
379 | I2C_FUNC_SMBUS_WORD_DATA)) | |
380 | return -ENODEV; | |
381 | ||
382 | regval = i2c_smbus_read_byte_data(client, MAX31730_REG_MFG_ID); | |
383 | if (regval != MAX31730_MFG_ID) | |
384 | return -ENODEV; | |
385 | regval = i2c_smbus_read_byte_data(client, MAX31730_REG_MFG_REV); | |
386 | if (regval != MAX31730_MFG_REV) | |
387 | return -ENODEV; | |
388 | ||
389 | /* lower 4 bit of temperature and limit registers must be 0 */ | |
390 | if (max31730_check_reg_temp(client, MAX31730_REG_TEMP_MIN)) | |
391 | return -ENODEV; | |
392 | ||
393 | for (i = 0; i < 4; i++) { | |
394 | if (max31730_check_reg_temp(client, MAX31730_REG_TEMP + i * 2)) | |
395 | return -ENODEV; | |
396 | if (max31730_check_reg_temp(client, | |
397 | MAX31730_REG_TEMP_MAX + i * 2)) | |
398 | return -ENODEV; | |
399 | } | |
400 | ||
f2f394db | 401 | strscpy(info->type, "max31730", I2C_NAME_SIZE); |
d21ed22b GR |
402 | |
403 | return 0; | |
404 | } | |
405 | ||
5ce951ab | 406 | static int max31730_suspend(struct device *dev) |
d21ed22b GR |
407 | { |
408 | struct max31730_data *data = dev_get_drvdata(dev); | |
409 | ||
410 | return max31730_write_config(data, MAX31730_STOP, 0); | |
411 | } | |
412 | ||
5ce951ab | 413 | static int max31730_resume(struct device *dev) |
d21ed22b GR |
414 | { |
415 | struct max31730_data *data = dev_get_drvdata(dev); | |
416 | ||
417 | return max31730_write_config(data, 0, MAX31730_STOP); | |
418 | } | |
419 | ||
5ce951ab | 420 | static DEFINE_SIMPLE_DEV_PM_OPS(max31730_pm_ops, max31730_suspend, max31730_resume); |
d21ed22b GR |
421 | |
422 | static struct i2c_driver max31730_driver = { | |
423 | .class = I2C_CLASS_HWMON, | |
424 | .driver = { | |
425 | .name = "max31730", | |
426 | .of_match_table = of_match_ptr(max31730_of_match), | |
5ce951ab | 427 | .pm = pm_sleep_ptr(&max31730_pm_ops), |
d21ed22b | 428 | }, |
1975d167 | 429 | .probe = max31730_probe, |
d21ed22b GR |
430 | .id_table = max31730_ids, |
431 | .detect = max31730_detect, | |
432 | .address_list = normal_i2c, | |
433 | }; | |
434 | ||
435 | module_i2c_driver(max31730_driver); | |
436 | ||
437 | MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); | |
438 | MODULE_DESCRIPTION("MAX31730 driver"); | |
439 | MODULE_LICENSE("GPL"); |