1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Hardware monitoring driver for Maxim MAX6621
4 *
5 * Copyright (c) 2017 Mellanox Technologies. All rights reserved.
6 * Copyright (c) 2017 Vadim Pasternak <vadimp@mellanox.com>
7 */
8
9 #include <linux/bitops.h>
10 #include <linux/hwmon.h>
11 #include <linux/hwmon-sysfs.h>
12 #include <linux/i2c.h>
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/regmap.h>
17
18 #define MAX6621_DRV_NAME "max6621"
19 #define MAX6621_TEMP_INPUT_REG_NUM 9
20 #define MAX6621_TEMP_INPUT_MIN -127000
21 #define MAX6621_TEMP_INPUT_MAX 128000
22 #define MAX6621_TEMP_ALERT_CHAN_SHIFT 1
23
24 #define MAX6621_TEMP_S0D0_REG 0x00
25 #define MAX6621_TEMP_S0D1_REG 0x01
26 #define MAX6621_TEMP_S1D0_REG 0x02
27 #define MAX6621_TEMP_S1D1_REG 0x03
28 #define MAX6621_TEMP_S2D0_REG 0x04
29 #define MAX6621_TEMP_S2D1_REG 0x05
30 #define MAX6621_TEMP_S3D0_REG 0x06
31 #define MAX6621_TEMP_S3D1_REG 0x07
32 #define MAX6621_TEMP_MAX_REG 0x08
33 #define MAX6621_TEMP_MAX_ADDR_REG 0x0a
34 #define MAX6621_TEMP_ALERT_CAUSE_REG 0x0b
35 #define MAX6621_CONFIG0_REG 0x0c
36 #define MAX6621_CONFIG1_REG 0x0d
37 #define MAX6621_CONFIG2_REG 0x0e
38 #define MAX6621_CONFIG3_REG 0x0f
39 #define MAX6621_TEMP_S0_ALERT_REG 0x10
40 #define MAX6621_TEMP_S1_ALERT_REG 0x11
41 #define MAX6621_TEMP_S2_ALERT_REG 0x12
42 #define MAX6621_TEMP_S3_ALERT_REG 0x13
43 #define MAX6621_CLEAR_ALERT_REG 0x15
44 #define MAX6621_REG_MAX (MAX6621_CLEAR_ALERT_REG + 1)
45 #define MAX6621_REG_TEMP_SHIFT 0x06
46
47 #define MAX6621_ENABLE_TEMP_ALERTS_BIT 4
48 #define MAX6621_ENABLE_I2C_CRC_BIT 5
49 #define MAX6621_ENABLE_ALTERNATE_DATA 6
50 #define MAX6621_ENABLE_LOCKUP_TO 7
51 #define MAX6621_ENABLE_S0D0_BIT 8
52 #define MAX6621_ENABLE_S3D1_BIT 15
53 #define MAX6621_ENABLE_TEMP_ALL GENMASK(MAX6621_ENABLE_S3D1_BIT, \
54 MAX6621_ENABLE_S0D0_BIT)
55 #define MAX6621_POLL_DELAY_MASK 0x5
56 #define MAX6621_CONFIG0_INIT (MAX6621_ENABLE_TEMP_ALL | \
57 BIT(MAX6621_ENABLE_LOCKUP_TO) | \
58 BIT(MAX6621_ENABLE_I2C_CRC_BIT) | \
59 MAX6621_POLL_DELAY_MASK)
60 #define MAX6621_PECI_BIT_TIME 0x2
61 #define MAX6621_PECI_RETRY_NUM 0x3
62 #define MAX6621_CONFIG1_INIT ((MAX6621_PECI_BIT_TIME << 8) | \
63 MAX6621_PECI_RETRY_NUM)
64
65 /* Error codes */
66 #define MAX6621_TRAN_FAILED 0x8100 /*
67 * PECI transaction failed for more
68 * than the configured number of
69 * consecutive retries.
70 */
71 #define MAX6621_POOL_DIS 0x8101 /*
72 * Polling disabled for requested
73 * socket/domain.
74 */
75 #define MAX6621_POOL_UNCOMPLETE 0x8102 /*
76 * First poll not yet completed for
77 * requested socket/domain (on
78 * startup).
79 */
80 #define MAX6621_SD_DIS 0x8103 /*
81 * Read maximum temperature requested,
82 * but no sockets/domains enabled or
83 * all enabled sockets/domains have
84 * errors; or read maximum temperature
85 * address requested, but read maximum
86 * temperature was not called.
87 */
88 #define MAX6621_ALERT_DIS 0x8104 /*
89 * Get alert socket/domain requested,
90 * but no alert active.
91 */
92 #define MAX6621_PECI_ERR_MIN 0x8000 /* Intel spec PECI error min value. */
93 #define MAX6621_PECI_ERR_MAX 0x80ff /* Intel spec PECI error max value. */
94
95 static const u32 max6621_temp_regs[] = {
96 MAX6621_TEMP_MAX_REG, MAX6621_TEMP_S0D0_REG, MAX6621_TEMP_S1D0_REG,
97 MAX6621_TEMP_S2D0_REG, MAX6621_TEMP_S3D0_REG, MAX6621_TEMP_S0D1_REG,
98 MAX6621_TEMP_S1D1_REG, MAX6621_TEMP_S2D1_REG, MAX6621_TEMP_S3D1_REG,
99 };
100
101 static const char *const max6621_temp_labels[] = {
102 "maximum",
103 "socket0_0",
104 "socket1_0",
105 "socket2_0",
106 "socket3_0",
107 "socket0_1",
108 "socket1_1",
109 "socket2_1",
110 "socket3_1",
111 };
112
113 static const int max6621_temp_alert_chan2reg[] = {
114 MAX6621_TEMP_S0_ALERT_REG,
115 MAX6621_TEMP_S1_ALERT_REG,
116 MAX6621_TEMP_S2_ALERT_REG,
117 MAX6621_TEMP_S3_ALERT_REG,
118 };
119
120 /**
121 * struct max6621_data - private data:
122 *
123 * @client: I2C client;
124 * @regmap: register map handle;
125 * @input_chan2reg: mapping from channel to register;
126 */
127 struct max6621_data {
128 struct i2c_client *client;
129 struct regmap *regmap;
130 int input_chan2reg[MAX6621_TEMP_INPUT_REG_NUM + 1];
131 };
132
max6621_temp_mc2reg(long val)133 static long max6621_temp_mc2reg(long val)
134 {
135 return (val / 1000L) << MAX6621_REG_TEMP_SHIFT;
136 }
137
138 static umode_t
max6621_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)139 max6621_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
140 int channel)
141 {
142 /* Skip channels which are not physically conncted. */
143 if (((struct max6621_data *)data)->input_chan2reg[channel] < 0)
144 return 0;
145
146 switch (type) {
147 case hwmon_temp:
148 switch (attr) {
149 case hwmon_temp_input:
150 case hwmon_temp_label:
151 case hwmon_temp_crit_alarm:
152 return 0444;
153 case hwmon_temp_offset:
154 case hwmon_temp_crit:
155 return 0644;
156 default:
157 break;
158 }
159 break;
160 default:
161 break;
162 }
163
164 return 0;
165 }
166
max6621_verify_reg_data(struct device * dev,int regval)167 static int max6621_verify_reg_data(struct device *dev, int regval)
168 {
169 if (regval >= MAX6621_PECI_ERR_MIN &&
170 regval <= MAX6621_PECI_ERR_MAX) {
171 dev_dbg(dev, "PECI error code - err 0x%04x.\n",
172 regval);
173
174 return -EIO;
175 }
176
177 switch (regval) {
178 case MAX6621_TRAN_FAILED:
179 dev_dbg(dev, "PECI transaction failed - err 0x%04x.\n",
180 regval);
181 return -EIO;
182 case MAX6621_POOL_DIS:
183 dev_dbg(dev, "Polling disabled - err 0x%04x.\n", regval);
184 return -EOPNOTSUPP;
185 case MAX6621_POOL_UNCOMPLETE:
186 dev_dbg(dev, "First poll not completed on startup - err 0x%04x.\n",
187 regval);
188 return -EIO;
189 case MAX6621_SD_DIS:
190 dev_dbg(dev, "Resource is disabled - err 0x%04x.\n", regval);
191 return -EOPNOTSUPP;
192 case MAX6621_ALERT_DIS:
193 dev_dbg(dev, "No alert active - err 0x%04x.\n", regval);
194 return -EOPNOTSUPP;
195 default:
196 return 0;
197 }
198 }
199
200 static int
max6621_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)201 max6621_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
202 int channel, long *val)
203 {
204 struct max6621_data *data = dev_get_drvdata(dev);
205 u32 regval;
206 int reg;
207 s8 temp;
208 int ret;
209
210 switch (type) {
211 case hwmon_temp:
212 switch (attr) {
213 case hwmon_temp_input:
214 reg = data->input_chan2reg[channel];
215 ret = regmap_read(data->regmap, reg, ®val);
216 if (ret)
217 return ret;
218
219 ret = max6621_verify_reg_data(dev, regval);
220 if (ret)
221 return ret;
222
223 /*
224 * Bit MAX6621_REG_TEMP_SHIFT represents 1 degree step.
225 * The temperature is given in two's complement and 8
226 * bits is used for the register conversion.
227 */
228 temp = (regval >> MAX6621_REG_TEMP_SHIFT);
229 *val = temp * 1000L;
230
231 break;
232 case hwmon_temp_offset:
233 ret = regmap_read(data->regmap, MAX6621_CONFIG2_REG,
234 ®val);
235 if (ret)
236 return ret;
237
238 ret = max6621_verify_reg_data(dev, regval);
239 if (ret)
240 return ret;
241
242 *val = (regval >> MAX6621_REG_TEMP_SHIFT) *
243 1000L;
244
245 break;
246 case hwmon_temp_crit:
247 channel -= MAX6621_TEMP_ALERT_CHAN_SHIFT;
248 reg = max6621_temp_alert_chan2reg[channel];
249 ret = regmap_read(data->regmap, reg, ®val);
250 if (ret)
251 return ret;
252
253 ret = max6621_verify_reg_data(dev, regval);
254 if (ret)
255 return ret;
256
257 *val = regval * 1000L;
258
259 break;
260 case hwmon_temp_crit_alarm:
261 /*
262 * Set val to zero to recover the case, when reading
263 * MAX6621_TEMP_ALERT_CAUSE_REG results in for example
264 * MAX6621_ALERT_DIS. Reading will return with error,
265 * but in such case alarm should be returned as 0.
266 */
267 *val = 0;
268 ret = regmap_read(data->regmap,
269 MAX6621_TEMP_ALERT_CAUSE_REG,
270 ®val);
271 if (ret)
272 return ret;
273
274 ret = max6621_verify_reg_data(dev, regval);
275 if (ret) {
276 /* Do not report error if alert is disabled. */
277 if (regval == MAX6621_ALERT_DIS)
278 return 0;
279 else
280 return ret;
281 }
282
283 /*
284 * Clear the alert automatically, using send-byte
285 * smbus protocol for clearing alert.
286 */
287 if (regval) {
288 ret = i2c_smbus_write_byte(data->client,
289 MAX6621_CLEAR_ALERT_REG);
290 if (ret)
291 return ret;
292 }
293
294 *val = !!regval;
295
296 break;
297 default:
298 return -EOPNOTSUPP;
299 }
300 break;
301
302 default:
303 return -EOPNOTSUPP;
304 }
305
306 return 0;
307 }
308
309 static int
max6621_write(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long val)310 max6621_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
311 int channel, long val)
312 {
313 struct max6621_data *data = dev_get_drvdata(dev);
314 u32 reg;
315
316 switch (type) {
317 case hwmon_temp:
318 switch (attr) {
319 case hwmon_temp_offset:
320 /* Clamp to allowed range to prevent overflow. */
321 val = clamp_val(val, MAX6621_TEMP_INPUT_MIN,
322 MAX6621_TEMP_INPUT_MAX);
323 val = max6621_temp_mc2reg(val);
324
325 return regmap_write(data->regmap,
326 MAX6621_CONFIG2_REG, val);
327 case hwmon_temp_crit:
328 channel -= MAX6621_TEMP_ALERT_CHAN_SHIFT;
329 reg = max6621_temp_alert_chan2reg[channel];
330 /* Clamp to allowed range to prevent overflow. */
331 val = clamp_val(val, MAX6621_TEMP_INPUT_MIN,
332 MAX6621_TEMP_INPUT_MAX);
333 val = val / 1000L;
334
335 return regmap_write(data->regmap, reg, val);
336 default:
337 return -EOPNOTSUPP;
338 }
339 break;
340
341 default:
342 return -EOPNOTSUPP;
343 }
344
345 return -EOPNOTSUPP;
346 }
347
348 static int
max6621_read_string(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,const char ** str)349 max6621_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
350 int channel, const char **str)
351 {
352 switch (type) {
353 case hwmon_temp:
354 switch (attr) {
355 case hwmon_temp_label:
356 *str = max6621_temp_labels[channel];
357 return 0;
358 default:
359 return -EOPNOTSUPP;
360 }
361 break;
362 default:
363 return -EOPNOTSUPP;
364 }
365
366 return -EOPNOTSUPP;
367 }
368
max6621_writeable_reg(struct device * dev,unsigned int reg)369 static bool max6621_writeable_reg(struct device *dev, unsigned int reg)
370 {
371 switch (reg) {
372 case MAX6621_CONFIG0_REG:
373 case MAX6621_CONFIG1_REG:
374 case MAX6621_CONFIG2_REG:
375 case MAX6621_CONFIG3_REG:
376 case MAX6621_TEMP_S0_ALERT_REG:
377 case MAX6621_TEMP_S1_ALERT_REG:
378 case MAX6621_TEMP_S2_ALERT_REG:
379 case MAX6621_TEMP_S3_ALERT_REG:
380 case MAX6621_TEMP_ALERT_CAUSE_REG:
381 return true;
382 }
383 return false;
384 }
385
max6621_readable_reg(struct device * dev,unsigned int reg)386 static bool max6621_readable_reg(struct device *dev, unsigned int reg)
387 {
388 switch (reg) {
389 case MAX6621_TEMP_S0D0_REG:
390 case MAX6621_TEMP_S0D1_REG:
391 case MAX6621_TEMP_S1D0_REG:
392 case MAX6621_TEMP_S1D1_REG:
393 case MAX6621_TEMP_S2D0_REG:
394 case MAX6621_TEMP_S2D1_REG:
395 case MAX6621_TEMP_S3D0_REG:
396 case MAX6621_TEMP_S3D1_REG:
397 case MAX6621_TEMP_MAX_REG:
398 case MAX6621_TEMP_MAX_ADDR_REG:
399 case MAX6621_CONFIG0_REG:
400 case MAX6621_CONFIG1_REG:
401 case MAX6621_CONFIG2_REG:
402 case MAX6621_CONFIG3_REG:
403 case MAX6621_TEMP_S0_ALERT_REG:
404 case MAX6621_TEMP_S1_ALERT_REG:
405 case MAX6621_TEMP_S2_ALERT_REG:
406 case MAX6621_TEMP_S3_ALERT_REG:
407 return true;
408 }
409 return false;
410 }
411
max6621_volatile_reg(struct device * dev,unsigned int reg)412 static bool max6621_volatile_reg(struct device *dev, unsigned int reg)
413 {
414 switch (reg) {
415 case MAX6621_TEMP_S0D0_REG:
416 case MAX6621_TEMP_S0D1_REG:
417 case MAX6621_TEMP_S1D0_REG:
418 case MAX6621_TEMP_S1D1_REG:
419 case MAX6621_TEMP_S2D0_REG:
420 case MAX6621_TEMP_S2D1_REG:
421 case MAX6621_TEMP_S3D0_REG:
422 case MAX6621_TEMP_S3D1_REG:
423 case MAX6621_TEMP_MAX_REG:
424 case MAX6621_TEMP_S0_ALERT_REG:
425 case MAX6621_TEMP_S1_ALERT_REG:
426 case MAX6621_TEMP_S2_ALERT_REG:
427 case MAX6621_TEMP_S3_ALERT_REG:
428 case MAX6621_TEMP_ALERT_CAUSE_REG:
429 return true;
430 }
431 return false;
432 }
433
434 static const struct reg_default max6621_regmap_default[] = {
435 { MAX6621_CONFIG0_REG, MAX6621_CONFIG0_INIT },
436 { MAX6621_CONFIG1_REG, MAX6621_CONFIG1_INIT },
437 };
438
439 static const struct regmap_config max6621_regmap_config = {
440 .reg_bits = 8,
441 .val_bits = 16,
442 .max_register = MAX6621_REG_MAX,
443 .val_format_endian = REGMAP_ENDIAN_LITTLE,
444 .cache_type = REGCACHE_FLAT,
445 .writeable_reg = max6621_writeable_reg,
446 .readable_reg = max6621_readable_reg,
447 .volatile_reg = max6621_volatile_reg,
448 .reg_defaults = max6621_regmap_default,
449 .num_reg_defaults = ARRAY_SIZE(max6621_regmap_default),
450 };
451
452 static const struct hwmon_channel_info * const max6621_info[] = {
453 HWMON_CHANNEL_INFO(chip,
454 HWMON_C_REGISTER_TZ),
455 HWMON_CHANNEL_INFO(temp,
456 HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_OFFSET,
457 HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_LABEL,
458 HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_LABEL,
459 HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_LABEL,
460 HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_LABEL,
461 HWMON_T_INPUT | HWMON_T_LABEL,
462 HWMON_T_INPUT | HWMON_T_LABEL,
463 HWMON_T_INPUT | HWMON_T_LABEL,
464 HWMON_T_INPUT | HWMON_T_LABEL),
465 NULL
466 };
467
468 static const struct hwmon_ops max6621_hwmon_ops = {
469 .read = max6621_read,
470 .write = max6621_write,
471 .read_string = max6621_read_string,
472 .is_visible = max6621_is_visible,
473 };
474
475 static const struct hwmon_chip_info max6621_chip_info = {
476 .ops = &max6621_hwmon_ops,
477 .info = max6621_info,
478 };
479
max6621_probe(struct i2c_client * client)480 static int max6621_probe(struct i2c_client *client)
481 {
482 struct device *dev = &client->dev;
483 struct max6621_data *data;
484 struct device *hwmon_dev;
485 int i;
486 int ret;
487
488 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
489 if (!data)
490 return -ENOMEM;
491
492 data->regmap = devm_regmap_init_i2c(client, &max6621_regmap_config);
493 if (IS_ERR(data->regmap))
494 return PTR_ERR(data->regmap);
495
496 i2c_set_clientdata(client, data);
497 data->client = client;
498
499 /* Set CONFIG0 register masking temperature alerts and PEC. */
500 ret = regmap_write(data->regmap, MAX6621_CONFIG0_REG,
501 MAX6621_CONFIG0_INIT);
502 if (ret)
503 return ret;
504
505 /* Set CONFIG1 register for PEC access retry number. */
506 ret = regmap_write(data->regmap, MAX6621_CONFIG1_REG,
507 MAX6621_CONFIG1_INIT);
508 if (ret)
509 return ret;
510
511 /* Sync registers with hardware. */
512 regcache_mark_dirty(data->regmap);
513 ret = regcache_sync(data->regmap);
514 if (ret)
515 return ret;
516
517 /* Verify which temperature input registers are enabled. */
518 for (i = 0; i < MAX6621_TEMP_INPUT_REG_NUM; i++) {
519 ret = i2c_smbus_read_word_data(client, max6621_temp_regs[i]);
520 if (ret < 0)
521 return ret;
522 ret = max6621_verify_reg_data(dev, ret);
523 if (ret) {
524 data->input_chan2reg[i] = -1;
525 continue;
526 }
527
528 data->input_chan2reg[i] = max6621_temp_regs[i];
529 }
530
531 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
532 data,
533 &max6621_chip_info,
534 NULL);
535
536 return PTR_ERR_OR_ZERO(hwmon_dev);
537 }
538
539 static const struct i2c_device_id max6621_id[] = {
540 { MAX6621_DRV_NAME },
541 { }
542 };
543 MODULE_DEVICE_TABLE(i2c, max6621_id);
544
545 static const struct of_device_id __maybe_unused max6621_of_match[] = {
546 { .compatible = "maxim,max6621" },
547 { }
548 };
549 MODULE_DEVICE_TABLE(of, max6621_of_match);
550
551 static struct i2c_driver max6621_driver = {
552 .driver = {
553 .name = MAX6621_DRV_NAME,
554 .of_match_table = of_match_ptr(max6621_of_match),
555 },
556 .probe = max6621_probe,
557 .id_table = max6621_id,
558 };
559
560 module_i2c_driver(max6621_driver);
561
562 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
563 MODULE_DESCRIPTION("Driver for Maxim MAX6621");
564 MODULE_LICENSE("GPL");
565