1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* tmp421.c
3 *
4 * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
5 * Preliminary support by:
6 * Melvin Rook, Raymond Ng
7 */
8
9 /*
10 * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
11 * Supported models: TMP421, TMP422, TMP423, TMP441, TMP442
12 */
13
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/slab.h>
17 #include <linux/jiffies.h>
18 #include <linux/i2c.h>
19 #include <linux/hwmon.h>
20 #include <linux/hwmon-sysfs.h>
21 #include <linux/err.h>
22 #include <linux/mutex.h>
23 #include <linux/of_device.h>
24 #include <linux/sysfs.h>
25
26 /* Addresses to scan */
27 static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
28 I2C_CLIENT_END };
29
30 enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 };
31
32 #define MAX_CHANNELS 4
33 /* The TMP421 registers */
34 #define TMP421_STATUS_REG 0x08
35 #define TMP421_CONFIG_REG_1 0x09
36 #define TMP421_CONFIG_REG_2 0x0A
37 #define TMP421_CONFIG_REG_REN(x) (BIT(3 + (x)))
38 #define TMP421_CONFIG_REG_REN_MASK GENMASK(6, 3)
39 #define TMP421_CONVERSION_RATE_REG 0x0B
40 #define TMP421_N_FACTOR_REG_1 0x21
41 #define TMP421_MANUFACTURER_ID_REG 0xFE
42 #define TMP421_DEVICE_ID_REG 0xFF
43
44 static const u8 TMP421_TEMP_MSB[MAX_CHANNELS] = { 0x00, 0x01, 0x02, 0x03 };
45 static const u8 TMP421_TEMP_LSB[MAX_CHANNELS] = { 0x10, 0x11, 0x12, 0x13 };
46
47 /* Flags */
48 #define TMP421_CONFIG_SHUTDOWN 0x40
49 #define TMP421_CONFIG_RANGE 0x04
50
51 /* Manufacturer / Device ID's */
52 #define TMP421_MANUFACTURER_ID 0x55
53 #define TMP421_DEVICE_ID 0x21
54 #define TMP422_DEVICE_ID 0x22
55 #define TMP423_DEVICE_ID 0x23
56 #define TMP441_DEVICE_ID 0x41
57 #define TMP442_DEVICE_ID 0x42
58
59 static const struct i2c_device_id tmp421_id[] = {
60 { "tmp421", 2 },
61 { "tmp422", 3 },
62 { "tmp423", 4 },
63 { "tmp441", 2 },
64 { "tmp442", 3 },
65 { }
66 };
67 MODULE_DEVICE_TABLE(i2c, tmp421_id);
68
69 static const struct of_device_id __maybe_unused tmp421_of_match[] = {
70 {
71 .compatible = "ti,tmp421",
72 .data = (void *)2
73 },
74 {
75 .compatible = "ti,tmp422",
76 .data = (void *)3
77 },
78 {
79 .compatible = "ti,tmp423",
80 .data = (void *)4
81 },
82 {
83 .compatible = "ti,tmp441",
84 .data = (void *)2
85 },
86 {
87 .compatible = "ti,tmp442",
88 .data = (void *)3
89 },
90 { },
91 };
92 MODULE_DEVICE_TABLE(of, tmp421_of_match);
93
94 struct tmp421_channel {
95 const char *label;
96 bool enabled;
97 s16 temp;
98 };
99
100 struct tmp421_data {
101 struct i2c_client *client;
102 struct mutex update_lock;
103 u32 temp_config[MAX_CHANNELS + 1];
104 struct hwmon_channel_info temp_info;
105 const struct hwmon_channel_info *info[2];
106 struct hwmon_chip_info chip;
107 bool valid;
108 unsigned long last_updated;
109 unsigned long channels;
110 u8 config;
111 struct tmp421_channel channel[MAX_CHANNELS];
112 };
113
temp_from_raw(u16 reg,bool extended)114 static int temp_from_raw(u16 reg, bool extended)
115 {
116 /* Mask out status bits */
117 int temp = reg & ~0xf;
118
119 if (extended)
120 temp = temp - 64 * 256;
121 else
122 temp = (s16)temp;
123
124 return DIV_ROUND_CLOSEST(temp * 1000, 256);
125 }
126
tmp421_update_device(struct tmp421_data * data)127 static int tmp421_update_device(struct tmp421_data *data)
128 {
129 struct i2c_client *client = data->client;
130 int ret = 0;
131 int i;
132
133 mutex_lock(&data->update_lock);
134
135 if (time_after(jiffies, data->last_updated + (HZ / 2)) ||
136 !data->valid) {
137 ret = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
138 if (ret < 0)
139 goto exit;
140 data->config = ret;
141
142 for (i = 0; i < data->channels; i++) {
143 ret = i2c_smbus_read_byte_data(client, TMP421_TEMP_MSB[i]);
144 if (ret < 0)
145 goto exit;
146 data->channel[i].temp = ret << 8;
147
148 ret = i2c_smbus_read_byte_data(client, TMP421_TEMP_LSB[i]);
149 if (ret < 0)
150 goto exit;
151 data->channel[i].temp |= ret;
152 }
153 data->last_updated = jiffies;
154 data->valid = true;
155 }
156
157 exit:
158 mutex_unlock(&data->update_lock);
159
160 if (ret < 0) {
161 data->valid = false;
162 return ret;
163 }
164
165 return 0;
166 }
167
tmp421_enable_channels(struct tmp421_data * data)168 static int tmp421_enable_channels(struct tmp421_data *data)
169 {
170 int err;
171 struct i2c_client *client = data->client;
172 struct device *dev = &client->dev;
173 int old = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_2);
174 int new, i;
175
176 if (old < 0) {
177 dev_err(dev, "error reading register, can't disable channels\n");
178 return old;
179 }
180
181 new = old & ~TMP421_CONFIG_REG_REN_MASK;
182 for (i = 0; i < data->channels; i++)
183 if (data->channel[i].enabled)
184 new |= TMP421_CONFIG_REG_REN(i);
185
186 if (new == old)
187 return 0;
188
189 err = i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_2, new);
190 if (err < 0)
191 dev_err(dev, "error writing register, can't disable channels\n");
192
193 return err;
194 }
195
tmp421_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)196 static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
197 u32 attr, int channel, long *val)
198 {
199 struct tmp421_data *tmp421 = dev_get_drvdata(dev);
200 int ret = 0;
201
202 ret = tmp421_update_device(tmp421);
203 if (ret)
204 return ret;
205
206 switch (attr) {
207 case hwmon_temp_input:
208 if (!tmp421->channel[channel].enabled)
209 return -ENODATA;
210 *val = temp_from_raw(tmp421->channel[channel].temp,
211 tmp421->config & TMP421_CONFIG_RANGE);
212 return 0;
213 case hwmon_temp_fault:
214 if (!tmp421->channel[channel].enabled)
215 return -ENODATA;
216 /*
217 * Any of OPEN or /PVLD bits indicate a hardware mulfunction
218 * and the conversion result may be incorrect
219 */
220 *val = !!(tmp421->channel[channel].temp & 0x03);
221 return 0;
222 case hwmon_temp_enable:
223 *val = tmp421->channel[channel].enabled;
224 return 0;
225 default:
226 return -EOPNOTSUPP;
227 }
228
229 }
230
tmp421_read_string(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,const char ** str)231 static int tmp421_read_string(struct device *dev, enum hwmon_sensor_types type,
232 u32 attr, int channel, const char **str)
233 {
234 struct tmp421_data *data = dev_get_drvdata(dev);
235
236 *str = data->channel[channel].label;
237
238 return 0;
239 }
240
tmp421_write(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long val)241 static int tmp421_write(struct device *dev, enum hwmon_sensor_types type,
242 u32 attr, int channel, long val)
243 {
244 struct tmp421_data *data = dev_get_drvdata(dev);
245 int ret;
246
247 switch (attr) {
248 case hwmon_temp_enable:
249 data->channel[channel].enabled = val;
250 ret = tmp421_enable_channels(data);
251 break;
252 default:
253 ret = -EOPNOTSUPP;
254 }
255
256 return ret;
257 }
258
tmp421_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)259 static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type,
260 u32 attr, int channel)
261 {
262 switch (attr) {
263 case hwmon_temp_fault:
264 case hwmon_temp_input:
265 return 0444;
266 case hwmon_temp_label:
267 return 0444;
268 case hwmon_temp_enable:
269 return 0644;
270 default:
271 return 0;
272 }
273 }
274
tmp421_init_client(struct tmp421_data * data)275 static int tmp421_init_client(struct tmp421_data *data)
276 {
277 int config, config_orig;
278 struct i2c_client *client = data->client;
279
280 /* Set the conversion rate to 2 Hz */
281 i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
282
283 /* Start conversions (disable shutdown if necessary) */
284 config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
285 if (config < 0) {
286 dev_err(&client->dev,
287 "Could not read configuration register (%d)\n", config);
288 return config;
289 }
290
291 config_orig = config;
292 config &= ~TMP421_CONFIG_SHUTDOWN;
293
294 if (config != config_orig) {
295 dev_info(&client->dev, "Enable monitoring chip\n");
296 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
297 }
298
299 return tmp421_enable_channels(data);
300 }
301
tmp421_detect(struct i2c_client * client,struct i2c_board_info * info)302 static int tmp421_detect(struct i2c_client *client,
303 struct i2c_board_info *info)
304 {
305 enum chips kind;
306 struct i2c_adapter *adapter = client->adapter;
307 static const char * const names[] = {
308 "TMP421", "TMP422", "TMP423",
309 "TMP441", "TMP442"
310 };
311 int addr = client->addr;
312 u8 reg;
313
314 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
315 return -ENODEV;
316
317 reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
318 if (reg != TMP421_MANUFACTURER_ID)
319 return -ENODEV;
320
321 reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
322 if (reg & 0xf8)
323 return -ENODEV;
324
325 reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
326 if (reg & 0x7f)
327 return -ENODEV;
328
329 reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
330 switch (reg) {
331 case TMP421_DEVICE_ID:
332 kind = tmp421;
333 break;
334 case TMP422_DEVICE_ID:
335 if (addr == 0x2a)
336 return -ENODEV;
337 kind = tmp422;
338 break;
339 case TMP423_DEVICE_ID:
340 if (addr != 0x4c && addr != 0x4d)
341 return -ENODEV;
342 kind = tmp423;
343 break;
344 case TMP441_DEVICE_ID:
345 kind = tmp441;
346 break;
347 case TMP442_DEVICE_ID:
348 if (addr != 0x4c && addr != 0x4d)
349 return -ENODEV;
350 kind = tmp442;
351 break;
352 default:
353 return -ENODEV;
354 }
355
356 strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
357 dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
358 names[kind], client->addr);
359
360 return 0;
361 }
362
tmp421_probe_child_from_dt(struct i2c_client * client,struct device_node * child,struct tmp421_data * data)363 static int tmp421_probe_child_from_dt(struct i2c_client *client,
364 struct device_node *child,
365 struct tmp421_data *data)
366
367 {
368 struct device *dev = &client->dev;
369 u32 i;
370 s32 val;
371 int err;
372
373 err = of_property_read_u32(child, "reg", &i);
374 if (err) {
375 dev_err(dev, "missing reg property of %pOFn\n", child);
376 return err;
377 }
378
379 if (i >= data->channels) {
380 dev_err(dev, "invalid reg %d of %pOFn\n", i, child);
381 return -EINVAL;
382 }
383
384 of_property_read_string(child, "label", &data->channel[i].label);
385 if (data->channel[i].label)
386 data->temp_config[i] |= HWMON_T_LABEL;
387
388 data->channel[i].enabled = of_device_is_available(child);
389
390 err = of_property_read_s32(child, "ti,n-factor", &val);
391 if (!err) {
392 if (i == 0) {
393 dev_err(dev, "n-factor can't be set for internal channel\n");
394 return -EINVAL;
395 }
396
397 if (val > 127 || val < -128) {
398 dev_err(dev, "n-factor for channel %d invalid (%d)\n",
399 i, val);
400 return -EINVAL;
401 }
402 i2c_smbus_write_byte_data(client, TMP421_N_FACTOR_REG_1 + i - 1,
403 val);
404 }
405
406 return 0;
407 }
408
tmp421_probe_from_dt(struct i2c_client * client,struct tmp421_data * data)409 static int tmp421_probe_from_dt(struct i2c_client *client, struct tmp421_data *data)
410 {
411 struct device *dev = &client->dev;
412 const struct device_node *np = dev->of_node;
413 struct device_node *child;
414 int err;
415
416 for_each_child_of_node(np, child) {
417 if (strcmp(child->name, "channel"))
418 continue;
419
420 err = tmp421_probe_child_from_dt(client, child, data);
421 if (err) {
422 of_node_put(child);
423 return err;
424 }
425 }
426
427 return 0;
428 }
429
430 static const struct hwmon_ops tmp421_ops = {
431 .is_visible = tmp421_is_visible,
432 .read = tmp421_read,
433 .read_string = tmp421_read_string,
434 .write = tmp421_write,
435 };
436
tmp421_probe(struct i2c_client * client)437 static int tmp421_probe(struct i2c_client *client)
438 {
439 struct device *dev = &client->dev;
440 struct device *hwmon_dev;
441 struct tmp421_data *data;
442 int i, err;
443
444 data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);
445 if (!data)
446 return -ENOMEM;
447
448 mutex_init(&data->update_lock);
449 if (client->dev.of_node)
450 data->channels = (unsigned long)
451 of_device_get_match_data(&client->dev);
452 else
453 data->channels = i2c_match_id(tmp421_id, client)->driver_data;
454 data->client = client;
455
456 for (i = 0; i < data->channels; i++) {
457 data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_ENABLE;
458 data->channel[i].enabled = true;
459 }
460
461 err = tmp421_probe_from_dt(client, data);
462 if (err)
463 return err;
464
465 err = tmp421_init_client(data);
466 if (err)
467 return err;
468
469 data->chip.ops = &tmp421_ops;
470 data->chip.info = data->info;
471
472 data->info[0] = &data->temp_info;
473
474 data->temp_info.type = hwmon_temp;
475 data->temp_info.config = data->temp_config;
476
477 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
478 data,
479 &data->chip,
480 NULL);
481 return PTR_ERR_OR_ZERO(hwmon_dev);
482 }
483
484 static struct i2c_driver tmp421_driver = {
485 .class = I2C_CLASS_HWMON,
486 .driver = {
487 .name = "tmp421",
488 .of_match_table = of_match_ptr(tmp421_of_match),
489 },
490 .probe_new = tmp421_probe,
491 .id_table = tmp421_id,
492 .detect = tmp421_detect,
493 .address_list = normal_i2c,
494 };
495
496 module_i2c_driver(tmp421_driver);
497
498 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
499 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");
500 MODULE_LICENSE("GPL");
501