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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Hardware monitoring driver for Maxim MAX6620
4 *
5 * Originally from L. Grunenberg.
6 * (C) 2012 by L. Grunenberg <contact@lgrunenberg.de>
7 *
8 * Copyright (c) 2021 Dell Inc. or its subsidiaries. All Rights Reserved.
9 *
10 * based on code written by :
11 * 2007 by Hans J. Koch <hjk@hansjkoch.de>
12 * John Morris <john.morris@spirentcom.com>
13 * Copyright (c) 2003 Spirent Communications
14 * and Claus Gindhart <claus.gindhart@kontron.com>
15 *
16 * This module has only been tested with the MAX6620 chip.
17 *
18 * The datasheet was last seen at:
19 *
20 * http://pdfserv.maxim-ic.com/en/ds/MAX6620.pdf
21 *
22 */
23
24#include <linux/bits.h>
25#include <linux/err.h>
26#include <linux/hwmon.h>
27#include <linux/i2c.h>
28#include <linux/init.h>
29#include <linux/jiffies.h>
30#include <linux/module.h>
31#include <linux/slab.h>
32
33/*
34 * MAX 6620 registers
35 */
36
37#define MAX6620_REG_CONFIG 0x00
38#define MAX6620_REG_FAULT 0x01
39#define MAX6620_REG_CONF_FAN0 0x02
40#define MAX6620_REG_CONF_FAN1 0x03
41#define MAX6620_REG_CONF_FAN2 0x04
42#define MAX6620_REG_CONF_FAN3 0x05
43#define MAX6620_REG_DYN_FAN0 0x06
44#define MAX6620_REG_DYN_FAN1 0x07
45#define MAX6620_REG_DYN_FAN2 0x08
46#define MAX6620_REG_DYN_FAN3 0x09
47#define MAX6620_REG_TACH0 0x10
48#define MAX6620_REG_TACH1 0x12
49#define MAX6620_REG_TACH2 0x14
50#define MAX6620_REG_TACH3 0x16
51#define MAX6620_REG_VOLT0 0x18
52#define MAX6620_REG_VOLT1 0x1A
53#define MAX6620_REG_VOLT2 0x1C
54#define MAX6620_REG_VOLT3 0x1E
55#define MAX6620_REG_TAR0 0x20
56#define MAX6620_REG_TAR1 0x22
57#define MAX6620_REG_TAR2 0x24
58#define MAX6620_REG_TAR3 0x26
59#define MAX6620_REG_DAC0 0x28
60#define MAX6620_REG_DAC1 0x2A
61#define MAX6620_REG_DAC2 0x2C
62#define MAX6620_REG_DAC3 0x2E
63
64/*
65 * Config register bits
66 */
67
68#define MAX6620_CFG_RUN BIT(7)
69#define MAX6620_CFG_POR BIT(6)
70#define MAX6620_CFG_TIMEOUT BIT(5)
71#define MAX6620_CFG_FULLFAN BIT(4)
72#define MAX6620_CFG_OSC BIT(3)
73#define MAX6620_CFG_WD_MASK (BIT(2) | BIT(1))
74#define MAX6620_CFG_WD_2 BIT(1)
75#define MAX6620_CFG_WD_6 BIT(2)
76#define MAX6620_CFG_WD10 (BIT(2) | BIT(1))
77#define MAX6620_CFG_WD BIT(0)
78
79/*
80 * Failure status register bits
81 */
82
83#define MAX6620_FAIL_TACH0 BIT(4)
84#define MAX6620_FAIL_TACH1 BIT(5)
85#define MAX6620_FAIL_TACH2 BIT(6)
86#define MAX6620_FAIL_TACH3 BIT(7)
87#define MAX6620_FAIL_MASK0 BIT(0)
88#define MAX6620_FAIL_MASK1 BIT(1)
89#define MAX6620_FAIL_MASK2 BIT(2)
90#define MAX6620_FAIL_MASK3 BIT(3)
91
92#define MAX6620_CLOCK_FREQ 8192 /* Clock frequency in Hz */
93#define MAX6620_PULSE_PER_REV 2 /* Tachometer pulses per revolution */
94
95/* Minimum and maximum values of the FAN-RPM */
96#define FAN_RPM_MIN 240
97#define FAN_RPM_MAX 30000
98
99static const u8 config_reg[] = {
100 MAX6620_REG_CONF_FAN0,
101 MAX6620_REG_CONF_FAN1,
102 MAX6620_REG_CONF_FAN2,
103 MAX6620_REG_CONF_FAN3,
104};
105
106static const u8 dyn_reg[] = {
107 MAX6620_REG_DYN_FAN0,
108 MAX6620_REG_DYN_FAN1,
109 MAX6620_REG_DYN_FAN2,
110 MAX6620_REG_DYN_FAN3,
111};
112
113static const u8 tach_reg[] = {
114 MAX6620_REG_TACH0,
115 MAX6620_REG_TACH1,
116 MAX6620_REG_TACH2,
117 MAX6620_REG_TACH3,
118};
119
120static const u8 target_reg[] = {
121 MAX6620_REG_TAR0,
122 MAX6620_REG_TAR1,
123 MAX6620_REG_TAR2,
124 MAX6620_REG_TAR3,
125};
126
127/*
128 * Client data (each client gets its own)
129 */
130
131struct max6620_data {
132 struct i2c_client *client;
133 struct mutex update_lock;
134 bool valid; /* false until following fields are valid */
135 unsigned long last_updated; /* in jiffies */
136
137 /* register values */
138 u8 fancfg[4];
139 u8 fandyn[4];
140 u8 fault;
141 u16 tach[4];
142 u16 target[4];
143};
144
145static u8 max6620_fan_div_from_reg(u8 val)
146{
147 return BIT((val & 0xE0) >> 5);
148}
149
150static u16 max6620_fan_rpm_to_tach(u8 div, int rpm)
151{
152 return (60 * div * MAX6620_CLOCK_FREQ) / (rpm * MAX6620_PULSE_PER_REV);
153}
154
155static int max6620_fan_tach_to_rpm(u8 div, u16 tach)
156{
157 return (60 * div * MAX6620_CLOCK_FREQ) / (tach * MAX6620_PULSE_PER_REV);
158}
159
160static int max6620_update_device(struct device *dev)
161{
162 struct max6620_data *data = dev_get_drvdata(dev);
163 struct i2c_client *client = data->client;
164 int i;
165 int ret = 0;
166
167 mutex_lock(&data->update_lock);
168
169 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
170 for (i = 0; i < 4; i++) {
171 ret = i2c_smbus_read_byte_data(client, config_reg[i]);
172 if (ret < 0)
173 goto error;
174 data->fancfg[i] = ret;
175
176 ret = i2c_smbus_read_byte_data(client, dyn_reg[i]);
177 if (ret < 0)
178 goto error;
179 data->fandyn[i] = ret;
180
181 ret = i2c_smbus_read_byte_data(client, tach_reg[i]);
182 if (ret < 0)
183 goto error;
184 data->tach[i] = (ret << 3) & 0x7f8;
185 ret = i2c_smbus_read_byte_data(client, tach_reg[i] + 1);
186 if (ret < 0)
187 goto error;
188 data->tach[i] |= (ret >> 5) & 0x7;
189
190 ret = i2c_smbus_read_byte_data(client, target_reg[i]);
191 if (ret < 0)
192 goto error;
193 data->target[i] = (ret << 3) & 0x7f8;
194 ret = i2c_smbus_read_byte_data(client, target_reg[i] + 1);
195 if (ret < 0)
196 goto error;
197 data->target[i] |= (ret >> 5) & 0x7;
198 }
199
200 /*
201 * Alarms are cleared on read in case the condition that
202 * caused the alarm is removed. Keep the value latched here
203 * for providing the register through different alarm files.
204 */
205 ret = i2c_smbus_read_byte_data(client, MAX6620_REG_FAULT);
206 if (ret < 0)
207 goto error;
208 data->fault |= (ret >> 4) & (ret & 0x0F);
209
210 data->last_updated = jiffies;
211 data->valid = true;
212 }
213
214error:
215 mutex_unlock(&data->update_lock);
216 return ret;
217}
218
219static umode_t
220max6620_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
221 int channel)
222{
223 switch (type) {
224 case hwmon_fan:
225 switch (attr) {
226 case hwmon_fan_alarm:
227 case hwmon_fan_input:
228 return 0444;
229 case hwmon_fan_div:
230 case hwmon_fan_target:
231 return 0644;
232 default:
233 break;
234 }
235 break;
236 default:
237 break;
238 }
239
240 return 0;
241}
242
243static int
244max6620_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
245 int channel, long *val)
246{
247 struct max6620_data *data;
248 struct i2c_client *client;
249 int ret;
250 u8 div;
251 u8 val1;
252 u8 val2;
253
254 ret = max6620_update_device(dev);
255 if (ret < 0)
256 return ret;
257 data = dev_get_drvdata(dev);
258 client = data->client;
259
260 switch (type) {
261 case hwmon_fan:
262 switch (attr) {
263 case hwmon_fan_alarm:
264 mutex_lock(&data->update_lock);
265 *val = !!(data->fault & BIT(channel));
266
267 /* Setting TACH count to re-enable fan fault detection */
268 if (*val == 1) {
269 val1 = (data->target[channel] >> 3) & 0xff;
270 val2 = (data->target[channel] << 5) & 0xe0;
271 ret = i2c_smbus_write_byte_data(client,
272 target_reg[channel], val1);
273 if (ret < 0) {
274 mutex_unlock(&data->update_lock);
275 return ret;
276 }
277 ret = i2c_smbus_write_byte_data(client,
278 target_reg[channel] + 1, val2);
279 if (ret < 0) {
280 mutex_unlock(&data->update_lock);
281 return ret;
282 }
283
284 data->fault &= ~BIT(channel);
285 }
286 mutex_unlock(&data->update_lock);
287
288 break;
289 case hwmon_fan_div:
290 *val = max6620_fan_div_from_reg(data->fandyn[channel]);
291 break;
292 case hwmon_fan_input:
293 if (data->tach[channel] == 0) {
294 *val = 0;
295 } else {
296 div = max6620_fan_div_from_reg(data->fandyn[channel]);
297 *val = max6620_fan_tach_to_rpm(div, data->tach[channel]);
298 }
299 break;
300 case hwmon_fan_target:
301 if (data->target[channel] == 0) {
302 *val = 0;
303 } else {
304 div = max6620_fan_div_from_reg(data->fandyn[channel]);
305 *val = max6620_fan_tach_to_rpm(div, data->target[channel]);
306 }
307 break;
308 default:
309 return -EOPNOTSUPP;
310 }
311 break;
312
313 default:
314 return -EOPNOTSUPP;
315 }
316
317 return 0;
318}
319
320static int
321max6620_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
322 int channel, long val)
323{
324 struct max6620_data *data;
325 struct i2c_client *client;
326 int ret;
327 u8 div;
328 u16 tach;
329 u8 val1;
330 u8 val2;
331
332 ret = max6620_update_device(dev);
333 if (ret < 0)
334 return ret;
335 data = dev_get_drvdata(dev);
336 client = data->client;
337 mutex_lock(&data->update_lock);
338
339 switch (type) {
340 case hwmon_fan:
341 switch (attr) {
342 case hwmon_fan_div:
343 switch (val) {
344 case 1:
345 div = 0;
346 break;
347 case 2:
348 div = 1;
349 break;
350 case 4:
351 div = 2;
352 break;
353 case 8:
354 div = 3;
355 break;
356 case 16:
357 div = 4;
358 break;
359 case 32:
360 div = 5;
361 break;
362 default:
363 ret = -EINVAL;
364 goto error;
365 }
366 data->fandyn[channel] &= 0x1F;
367 data->fandyn[channel] |= div << 5;
368 ret = i2c_smbus_write_byte_data(client, dyn_reg[channel],
369 data->fandyn[channel]);
370 break;
371 case hwmon_fan_target:
372 val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
373 div = max6620_fan_div_from_reg(data->fandyn[channel]);
374 tach = max6620_fan_rpm_to_tach(div, val);
375 val1 = (tach >> 3) & 0xff;
376 val2 = (tach << 5) & 0xe0;
377 ret = i2c_smbus_write_byte_data(client, target_reg[channel], val1);
378 if (ret < 0)
379 break;
380 ret = i2c_smbus_write_byte_data(client, target_reg[channel] + 1, val2);
381 if (ret < 0)
382 break;
383
384 /* Setting TACH count re-enables fan fault detection */
385 data->fault &= ~BIT(channel);
386
387 break;
388 default:
389 ret = -EOPNOTSUPP;
390 break;
391 }
392 break;
393
394 default:
395 ret = -EOPNOTSUPP;
396 break;
397 }
398
399error:
400 mutex_unlock(&data->update_lock);
401 return ret;
402}
403
404static const struct hwmon_channel_info *max6620_info[] = {
405 HWMON_CHANNEL_INFO(fan,
406 HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
407 HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
408 HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
409 HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM),
410 NULL
411};
412
413static const struct hwmon_ops max6620_hwmon_ops = {
414 .read = max6620_read,
415 .write = max6620_write,
416 .is_visible = max6620_is_visible,
417};
418
419static const struct hwmon_chip_info max6620_chip_info = {
420 .ops = &max6620_hwmon_ops,
421 .info = max6620_info,
422};
423
424static int max6620_init_client(struct max6620_data *data)
425{
426 struct i2c_client *client = data->client;
427 int config;
428 int err;
429 int i;
430 int reg;
431
432 config = i2c_smbus_read_byte_data(client, MAX6620_REG_CONFIG);
433 if (config < 0) {
434 dev_err(&client->dev, "Error reading config, aborting.\n");
435 return config;
436 }
437
438 /*
439 * Set bit 4, disable other fans from going full speed on a fail
440 * failure.
441 */
442 err = i2c_smbus_write_byte_data(client, MAX6620_REG_CONFIG, config | 0x10);
443 if (err < 0) {
444 dev_err(&client->dev, "Config write error, aborting.\n");
445 return err;
446 }
447
448 for (i = 0; i < 4; i++) {
449 reg = i2c_smbus_read_byte_data(client, config_reg[i]);
450 if (reg < 0)
451 return reg;
452 data->fancfg[i] = reg;
453
454 /* Enable RPM mode */
455 data->fancfg[i] |= 0xa8;
456 err = i2c_smbus_write_byte_data(client, config_reg[i], data->fancfg[i]);
457 if (err < 0)
458 return err;
459
460 /* 2 counts (001) and Rate change 100 (0.125 secs) */
461 data->fandyn[i] = 0x30;
462 err = i2c_smbus_write_byte_data(client, dyn_reg[i], data->fandyn[i]);
463 if (err < 0)
464 return err;
465 }
466 return 0;
467}
468
469static int max6620_probe(struct i2c_client *client)
470{
471 struct device *dev = &client->dev;
472 struct max6620_data *data;
473 struct device *hwmon_dev;
474 int err;
475
476 data = devm_kzalloc(dev, sizeof(struct max6620_data), GFP_KERNEL);
477 if (!data)
478 return -ENOMEM;
479
480 data->client = client;
481 mutex_init(&data->update_lock);
482
483 err = max6620_init_client(data);
484 if (err)
485 return err;
486
487 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
488 data,
489 &max6620_chip_info,
490 NULL);
491
492 return PTR_ERR_OR_ZERO(hwmon_dev);
493}
494
495static const struct i2c_device_id max6620_id[] = {
496 { "max6620", 0 },
497 { }
498};
499MODULE_DEVICE_TABLE(i2c, max6620_id);
500
501static struct i2c_driver max6620_driver = {
502 .class = I2C_CLASS_HWMON,
503 .driver = {
504 .name = "max6620",
505 },
506 .probe_new = max6620_probe,
507 .id_table = max6620_id,
508};
509
510module_i2c_driver(max6620_driver);
511
512MODULE_AUTHOR("Lucas Grunenberg");
513MODULE_DESCRIPTION("MAX6620 sensor driver");
514MODULE_LICENSE("GPL");