1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * max31790.c - Part of lm_sensors, Linux kernel modules for hardware
4 * monitoring.
5 *
6 * (C) 2015 by Il Han <corone.il.han@gmail.com>
7 */
8
9#include <linux/err.h>
10#include <linux/hwmon.h>
11#include <linux/i2c.h>
12#include <linux/init.h>
13#include <linux/jiffies.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16
17/* MAX31790 registers */
18#define MAX31790_REG_GLOBAL_CONFIG 0x00
19#define MAX31790_REG_FAN_CONFIG(ch) (0x02 + (ch))
20#define MAX31790_REG_FAN_DYNAMICS(ch) (0x08 + (ch))
21#define MAX31790_REG_FAN_FAULT_STATUS2 0x10
22#define MAX31790_REG_FAN_FAULT_STATUS1 0x11
23#define MAX31790_REG_TACH_COUNT(ch) (0x18 + (ch) * 2)
24#define MAX31790_REG_PWM_DUTY_CYCLE(ch) (0x30 + (ch) * 2)
25#define MAX31790_REG_PWMOUT(ch) (0x40 + (ch) * 2)
26#define MAX31790_REG_TARGET_COUNT(ch) (0x50 + (ch) * 2)
27
28/* Fan Config register bits */
29#define MAX31790_FAN_CFG_RPM_MODE 0x80
30#define MAX31790_FAN_CFG_CTRL_MON 0x10
31#define MAX31790_FAN_CFG_TACH_INPUT_EN 0x08
32#define MAX31790_FAN_CFG_TACH_INPUT 0x01
33
34/* Fan Dynamics register bits */
35#define MAX31790_FAN_DYN_SR_SHIFT 5
36#define MAX31790_FAN_DYN_SR_MASK 0xE0
37#define SR_FROM_REG(reg) (((reg) & MAX31790_FAN_DYN_SR_MASK) \
38 >> MAX31790_FAN_DYN_SR_SHIFT)
39
40#define FAN_RPM_MIN 120
41#define FAN_RPM_MAX 7864320
42
43#define FAN_COUNT_REG_MAX 0xffe0
44
45#define RPM_FROM_REG(reg, sr) (((reg) >> 4) ? \
46 ((60 * (sr) * 8192) / ((reg) >> 4)) : \
47 FAN_RPM_MAX)
48#define RPM_TO_REG(rpm, sr) ((60 * (sr) * 8192) / ((rpm) * 2))
49
50#define NR_CHANNEL 6
51
52#define PWM_INPUT_SCALE 255
53#define MAX31790_REG_PWMOUT_SCALE 511
54
55/*
56 * Client data (each client gets its own)
57 */
58struct max31790_data {
59 struct i2c_client *client;
60 bool valid; /* zero until following fields are valid */
61 unsigned long last_updated; /* in jiffies */
62
63 /* register values */
64 u8 fan_config[NR_CHANNEL];
65 u8 fan_dynamics[NR_CHANNEL];
66 u16 fault_status;
67 u16 tach[NR_CHANNEL * 2];
68 u16 pwm[NR_CHANNEL];
69 u16 target_count[NR_CHANNEL];
70};
71
72static struct max31790_data *max31790_update_device(struct device *dev)
73{
74 struct max31790_data *data = dev_get_drvdata(dev);
75 struct i2c_client *client = data->client;
76 int i, rv;
77
78 if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
79 data->valid = false;
80 rv = i2c_smbus_read_byte_data(client,
81 MAX31790_REG_FAN_FAULT_STATUS1);
82 if (rv < 0)
83 return ERR_PTR(error: rv);
84 data->fault_status |= rv & 0x3F;
85
86 rv = i2c_smbus_read_byte_data(client,
87 MAX31790_REG_FAN_FAULT_STATUS2);
88 if (rv < 0)
89 return ERR_PTR(error: rv);
90 data->fault_status |= (rv & 0x3F) << 6;
91
92 for (i = 0; i < NR_CHANNEL; i++) {
93 rv = i2c_smbus_read_word_swapped(client,
94 MAX31790_REG_TACH_COUNT(i));
95 if (rv < 0)
96 return ERR_PTR(error: rv);
97 data->tach[i] = rv;
98
99 if (data->fan_config[i]
100 & MAX31790_FAN_CFG_TACH_INPUT) {
101 rv = i2c_smbus_read_word_swapped(client,
102 MAX31790_REG_TACH_COUNT(NR_CHANNEL
103 + i));
104 if (rv < 0)
105 return ERR_PTR(error: rv);
106 data->tach[NR_CHANNEL + i] = rv;
107 } else {
108 rv = i2c_smbus_read_word_swapped(client,
109 MAX31790_REG_PWM_DUTY_CYCLE(i));
110 if (rv < 0)
111 return ERR_PTR(error: rv);
112 data->pwm[i] = rv;
113
114 rv = i2c_smbus_read_word_swapped(client,
115 MAX31790_REG_TARGET_COUNT(i));
116 if (rv < 0)
117 return ERR_PTR(error: rv);
118 data->target_count[i] = rv;
119 }
120 }
121
122 data->last_updated = jiffies;
123 data->valid = true;
124 }
125 return data;
126}
127
128static const u8 tach_period[8] = { 1, 2, 4, 8, 16, 32, 32, 32 };
129
130static u8 get_tach_period(u8 fan_dynamics)
131{
132 return tach_period[SR_FROM_REG(fan_dynamics)];
133}
134
135static u8 bits_for_tach_period(int rpm)
136{
137 u8 bits;
138
139 if (rpm < 500)
140 bits = 0x0;
141 else if (rpm < 1000)
142 bits = 0x1;
143 else if (rpm < 2000)
144 bits = 0x2;
145 else if (rpm < 4000)
146 bits = 0x3;
147 else if (rpm < 8000)
148 bits = 0x4;
149 else
150 bits = 0x5;
151
152 return bits;
153}
154
155static int max31790_read_fan(struct device *dev, u32 attr, int channel,
156 long *val)
157{
158 struct max31790_data *data = max31790_update_device(dev);
159 int sr, rpm;
160
161 if (IS_ERR(ptr: data))
162 return PTR_ERR(ptr: data);
163
164 switch (attr) {
165 case hwmon_fan_input:
166 sr = get_tach_period(fan_dynamics: data->fan_dynamics[channel % NR_CHANNEL]);
167 if (data->tach[channel] == FAN_COUNT_REG_MAX)
168 rpm = 0;
169 else
170 rpm = RPM_FROM_REG(data->tach[channel], sr);
171 *val = rpm;
172 return 0;
173 case hwmon_fan_target:
174 sr = get_tach_period(fan_dynamics: data->fan_dynamics[channel]);
175 rpm = RPM_FROM_REG(data->target_count[channel], sr);
176 *val = rpm;
177 return 0;
178 case hwmon_fan_fault:
179 *val = !!(data->fault_status & (1 << channel));
180 data->fault_status &= ~(1 << channel);
181 /*
182 * If a fault bit is set, we need to write into one of the fan
183 * configuration registers to clear it. Note that this also
184 * clears the fault for the companion channel if enabled.
185 */
186 if (*val) {
187 int reg = MAX31790_REG_TARGET_COUNT(channel % NR_CHANNEL);
188
189 return i2c_smbus_write_byte_data(client: data->client, command: reg,
190 value: data->target_count[channel % NR_CHANNEL] >> 8);
191 }
192 return 0;
193 case hwmon_fan_enable:
194 *val = !!(data->fan_config[channel] & MAX31790_FAN_CFG_TACH_INPUT_EN);
195 return 0;
196 default:
197 return -EOPNOTSUPP;
198 }
199}
200
201static int max31790_write_fan(struct device *dev, u32 attr, int channel,
202 long val)
203{
204 struct max31790_data *data = dev_get_drvdata(dev);
205 struct i2c_client *client = data->client;
206 int target_count;
207 int err = 0;
208 u8 bits, fan_config;
209 int sr;
210
211 switch (attr) {
212 case hwmon_fan_target:
213 val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
214 bits = bits_for_tach_period(rpm: val);
215 data->fan_dynamics[channel] =
216 ((data->fan_dynamics[channel] &
217 ~MAX31790_FAN_DYN_SR_MASK) |
218 (bits << MAX31790_FAN_DYN_SR_SHIFT));
219 err = i2c_smbus_write_byte_data(client,
220 MAX31790_REG_FAN_DYNAMICS(channel),
221 value: data->fan_dynamics[channel]);
222 if (err < 0)
223 break;
224
225 sr = get_tach_period(fan_dynamics: data->fan_dynamics[channel]);
226 target_count = RPM_TO_REG(val, sr);
227 target_count = clamp_val(target_count, 0x1, 0x7FF);
228
229 data->target_count[channel] = target_count << 5;
230
231 err = i2c_smbus_write_word_swapped(client,
232 MAX31790_REG_TARGET_COUNT(channel),
233 value: data->target_count[channel]);
234 break;
235 case hwmon_fan_enable:
236 fan_config = data->fan_config[channel];
237 if (val == 0) {
238 fan_config &= ~MAX31790_FAN_CFG_TACH_INPUT_EN;
239 } else if (val == 1) {
240 fan_config |= MAX31790_FAN_CFG_TACH_INPUT_EN;
241 } else {
242 err = -EINVAL;
243 break;
244 }
245 if (fan_config != data->fan_config[channel]) {
246 err = i2c_smbus_write_byte_data(client, MAX31790_REG_FAN_CONFIG(channel),
247 value: fan_config);
248 if (!err)
249 data->fan_config[channel] = fan_config;
250 }
251 break;
252 default:
253 err = -EOPNOTSUPP;
254 break;
255 }
256 return err;
257}
258
259static umode_t max31790_fan_is_visible(const void *_data, u32 attr, int channel)
260{
261 const struct max31790_data *data = _data;
262 u8 fan_config = data->fan_config[channel % NR_CHANNEL];
263
264 switch (attr) {
265 case hwmon_fan_input:
266 case hwmon_fan_fault:
267 if (channel < NR_CHANNEL ||
268 (fan_config & MAX31790_FAN_CFG_TACH_INPUT))
269 return 0444;
270 return 0;
271 case hwmon_fan_target:
272 if (channel < NR_CHANNEL &&
273 !(fan_config & MAX31790_FAN_CFG_TACH_INPUT))
274 return 0644;
275 return 0;
276 case hwmon_fan_enable:
277 if (channel < NR_CHANNEL)
278 return 0644;
279 return 0;
280 default:
281 return 0;
282 }
283}
284
285static int max31790_read_pwm(struct device *dev, u32 attr, int channel,
286 long *val)
287{
288 struct max31790_data *data = max31790_update_device(dev);
289 u8 fan_config;
290
291 if (IS_ERR(ptr: data))
292 return PTR_ERR(ptr: data);
293
294 fan_config = data->fan_config[channel];
295
296 switch (attr) {
297 case hwmon_pwm_input:
298 *val = data->pwm[channel] >> 8;
299 return 0;
300 case hwmon_pwm_enable:
301 if (fan_config & MAX31790_FAN_CFG_CTRL_MON)
302 *val = 0;
303 else if (fan_config & MAX31790_FAN_CFG_RPM_MODE)
304 *val = 2;
305 else
306 *val = 1;
307 return 0;
308 default:
309 return -EOPNOTSUPP;
310 }
311}
312
313static int max31790_write_pwm(struct device *dev, u32 attr, int channel,
314 long val)
315{
316 struct max31790_data *data = dev_get_drvdata(dev);
317 struct i2c_client *client = data->client;
318 u8 fan_config;
319 int err = 0;
320
321 switch (attr) {
322 case hwmon_pwm_input:
323 if (val < 0 || val > 255) {
324 err = -EINVAL;
325 break;
326 }
327
328 val = DIV_ROUND_CLOSEST(val * MAX31790_REG_PWMOUT_SCALE,
329 PWM_INPUT_SCALE);
330 data->valid = false;
331 err = i2c_smbus_write_word_swapped(client,
332 MAX31790_REG_PWMOUT(channel),
333 value: val << 7);
334 break;
335 case hwmon_pwm_enable:
336 fan_config = data->fan_config[channel];
337 if (val == 0) {
338 fan_config |= MAX31790_FAN_CFG_CTRL_MON;
339 /*
340 * Disable RPM mode; otherwise disabling fan speed
341 * monitoring is not possible.
342 */
343 fan_config &= ~MAX31790_FAN_CFG_RPM_MODE;
344 } else if (val == 1) {
345 fan_config &= ~(MAX31790_FAN_CFG_CTRL_MON | MAX31790_FAN_CFG_RPM_MODE);
346 } else if (val == 2) {
347 fan_config &= ~MAX31790_FAN_CFG_CTRL_MON;
348 /*
349 * The chip sets MAX31790_FAN_CFG_TACH_INPUT_EN on its
350 * own if MAX31790_FAN_CFG_RPM_MODE is set.
351 * Do it here as well to reflect the actual register
352 * value in the cache.
353 */
354 fan_config |= (MAX31790_FAN_CFG_RPM_MODE | MAX31790_FAN_CFG_TACH_INPUT_EN);
355 } else {
356 err = -EINVAL;
357 break;
358 }
359 if (fan_config != data->fan_config[channel]) {
360 err = i2c_smbus_write_byte_data(client, MAX31790_REG_FAN_CONFIG(channel),
361 value: fan_config);
362 if (!err)
363 data->fan_config[channel] = fan_config;
364 }
365 break;
366 default:
367 err = -EOPNOTSUPP;
368 break;
369 }
370 return err;
371}
372
373static umode_t max31790_pwm_is_visible(const void *_data, u32 attr, int channel)
374{
375 const struct max31790_data *data = _data;
376 u8 fan_config = data->fan_config[channel];
377
378 switch (attr) {
379 case hwmon_pwm_input:
380 case hwmon_pwm_enable:
381 if (!(fan_config & MAX31790_FAN_CFG_TACH_INPUT))
382 return 0644;
383 return 0;
384 default:
385 return 0;
386 }
387}
388
389static int max31790_read(struct device *dev, enum hwmon_sensor_types type,
390 u32 attr, int channel, long *val)
391{
392 switch (type) {
393 case hwmon_fan:
394 return max31790_read_fan(dev, attr, channel, val);
395 case hwmon_pwm:
396 return max31790_read_pwm(dev, attr, channel, val);
397 default:
398 return -EOPNOTSUPP;
399 }
400}
401
402static int max31790_write(struct device *dev, enum hwmon_sensor_types type,
403 u32 attr, int channel, long val)
404{
405 switch (type) {
406 case hwmon_fan:
407 return max31790_write_fan(dev, attr, channel, val);
408 case hwmon_pwm:
409 return max31790_write_pwm(dev, attr, channel, val);
410 default:
411 return -EOPNOTSUPP;
412 }
413}
414
415static umode_t max31790_is_visible(const void *data,
416 enum hwmon_sensor_types type,
417 u32 attr, int channel)
418{
419 switch (type) {
420 case hwmon_fan:
421 return max31790_fan_is_visible(data: data, attr, channel);
422 case hwmon_pwm:
423 return max31790_pwm_is_visible(data: data, attr, channel);
424 default:
425 return 0;
426 }
427}
428
429static const struct hwmon_channel_info * const max31790_info[] = {
430 HWMON_CHANNEL_INFO(fan,
431 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
432 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
433 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
434 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
435 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
436 HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_FAULT | HWMON_F_ENABLE,
437 HWMON_F_INPUT | HWMON_F_FAULT,
438 HWMON_F_INPUT | HWMON_F_FAULT,
439 HWMON_F_INPUT | HWMON_F_FAULT,
440 HWMON_F_INPUT | HWMON_F_FAULT,
441 HWMON_F_INPUT | HWMON_F_FAULT,
442 HWMON_F_INPUT | HWMON_F_FAULT),
443 HWMON_CHANNEL_INFO(pwm,
444 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
445 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
446 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
447 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
448 HWMON_PWM_INPUT | HWMON_PWM_ENABLE,
449 HWMON_PWM_INPUT | HWMON_PWM_ENABLE),
450 NULL
451};
452
453static const struct hwmon_ops max31790_hwmon_ops = {
454 .is_visible = max31790_is_visible,
455 .read = max31790_read,
456 .write = max31790_write,
457};
458
459static const struct hwmon_chip_info max31790_chip_info = {
460 .ops = &max31790_hwmon_ops,
461 .info = max31790_info,
462};
463
464static int max31790_init_client(struct i2c_client *client,
465 struct max31790_data *data)
466{
467 int i, rv;
468
469 for (i = 0; i < NR_CHANNEL; i++) {
470 rv = i2c_smbus_read_byte_data(client,
471 MAX31790_REG_FAN_CONFIG(i));
472 if (rv < 0)
473 return rv;
474 data->fan_config[i] = rv;
475
476 rv = i2c_smbus_read_byte_data(client,
477 MAX31790_REG_FAN_DYNAMICS(i));
478 if (rv < 0)
479 return rv;
480 data->fan_dynamics[i] = rv;
481 }
482
483 return 0;
484}
485
486static int max31790_probe(struct i2c_client *client)
487{
488 struct i2c_adapter *adapter = client->adapter;
489 struct device *dev = &client->dev;
490 struct max31790_data *data;
491 struct device *hwmon_dev;
492 int err;
493
494 if (!i2c_check_functionality(adap: adapter,
495 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
496 return -ENODEV;
497
498 data = devm_kzalloc(dev, size: sizeof(struct max31790_data), GFP_KERNEL);
499 if (!data)
500 return -ENOMEM;
501
502 data->client = client;
503
504 /*
505 * Initialize the max31790 chip
506 */
507 err = max31790_init_client(client, data);
508 if (err)
509 return err;
510
511 hwmon_dev = devm_hwmon_device_register_with_info(dev, name: client->name,
512 drvdata: data,
513 info: &max31790_chip_info,
514 NULL);
515
516 return PTR_ERR_OR_ZERO(ptr: hwmon_dev);
517}
518
519static const struct i2c_device_id max31790_id[] = {
520 { "max31790" },
521 { }
522};
523MODULE_DEVICE_TABLE(i2c, max31790_id);
524
525static struct i2c_driver max31790_driver = {
526 .probe = max31790_probe,
527 .driver = {
528 .name = "max31790",
529 },
530 .id_table = max31790_id,
531};
532
533module_i2c_driver(max31790_driver);
534
535MODULE_AUTHOR("Il Han <corone.il.han@gmail.com>");
536MODULE_DESCRIPTION("MAX31790 sensor driver");
537MODULE_LICENSE("GPL");
538

source code of linux/drivers/hwmon/max31790.c