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10#include <linux/hwmon.h>
11#include <linux/interrupt.h>
12#include <linux/module.h>
13#include <linux/mutex.h>
14#include <linux/of.h>
15#include <linux/platform_device.h>
16#include <linux/pwm.h>
17#include <linux/regulator/consumer.h>
18#include <linux/sysfs.h>
19#include <linux/thermal.h>
20#include <linux/timer.h>
21
22#define MAX_PWM 255
23
24struct pwm_fan_tach {
25 int irq;
26 atomic_t pulses;
27 unsigned int rpm;
28 u8 pulses_per_revolution;
29};
30
31struct pwm_fan_ctx {
32 struct mutex lock;
33 struct pwm_device *pwm;
34 struct pwm_state pwm_state;
35 struct regulator *reg_en;
36
37 int tach_count;
38 struct pwm_fan_tach *tachs;
39 ktime_t sample_start;
40 struct timer_list rpm_timer;
41
42 unsigned int pwm_value;
43 unsigned int pwm_fan_state;
44 unsigned int pwm_fan_max_state;
45 unsigned int *pwm_fan_cooling_levels;
46 struct thermal_cooling_device *cdev;
47
48 struct hwmon_chip_info info;
49 struct hwmon_channel_info fan_channel;
50};
51
52static const u32 pwm_fan_channel_config_pwm[] = {
53 HWMON_PWM_INPUT,
54 0
55};
56
57static const struct hwmon_channel_info pwm_fan_channel_pwm = {
58 .type = hwmon_pwm,
59 .config = pwm_fan_channel_config_pwm,
60};
61
62
63static irqreturn_t pulse_handler(int irq, void *dev_id)
64{
65 struct pwm_fan_tach *tach = dev_id;
66
67 atomic_inc(&tach->pulses);
68
69 return IRQ_HANDLED;
70}
71
72static void sample_timer(struct timer_list *t)
73{
74 struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
75 unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start);
76 int i;
77
78 if (delta) {
79 for (i = 0; i < ctx->tach_count; i++) {
80 struct pwm_fan_tach *tach = &ctx->tachs[i];
81 int pulses;
82
83 pulses = atomic_read(&tach->pulses);
84 atomic_sub(pulses, &tach->pulses);
85 tach->rpm = (unsigned int)(pulses * 1000 * 60) /
86 (tach->pulses_per_revolution * delta);
87 }
88
89 ctx->sample_start = ktime_get();
90 }
91
92 mod_timer(&ctx->rpm_timer, jiffies + HZ);
93}
94
95static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
96{
97 unsigned long period;
98 int ret = 0;
99 struct pwm_state *state = &ctx->pwm_state;
100
101 mutex_lock(&ctx->lock);
102 if (ctx->pwm_value == pwm)
103 goto exit_set_pwm_err;
104
105 period = state->period;
106 state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
107 state->enabled = pwm ? true : false;
108
109 ret = pwm_apply_state(ctx->pwm, state);
110 if (!ret)
111 ctx->pwm_value = pwm;
112exit_set_pwm_err:
113 mutex_unlock(&ctx->lock);
114 return ret;
115}
116
117static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
118{
119 int i;
120
121 for (i = 0; i < ctx->pwm_fan_max_state; ++i)
122 if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
123 break;
124
125 ctx->pwm_fan_state = i;
126}
127
128static int pwm_fan_write(struct device *dev, enum hwmon_sensor_types type,
129 u32 attr, int channel, long val)
130{
131 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
132 int ret;
133
134 if (val < 0 || val > MAX_PWM)
135 return -EINVAL;
136
137 ret = __set_pwm(ctx, val);
138 if (ret)
139 return ret;
140
141 pwm_fan_update_state(ctx, val);
142 return 0;
143}
144
145static int pwm_fan_read(struct device *dev, enum hwmon_sensor_types type,
146 u32 attr, int channel, long *val)
147{
148 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
149
150 switch (type) {
151 case hwmon_pwm:
152 *val = ctx->pwm_value;
153 return 0;
154
155 case hwmon_fan:
156 *val = ctx->tachs[channel].rpm;
157 return 0;
158
159 default:
160 return -ENOTSUPP;
161 }
162}
163
164static umode_t pwm_fan_is_visible(const void *data,
165 enum hwmon_sensor_types type,
166 u32 attr, int channel)
167{
168 switch (type) {
169 case hwmon_pwm:
170 return 0644;
171
172 case hwmon_fan:
173 return 0444;
174
175 default:
176 return 0;
177 }
178}
179
180static const struct hwmon_ops pwm_fan_hwmon_ops = {
181 .is_visible = pwm_fan_is_visible,
182 .read = pwm_fan_read,
183 .write = pwm_fan_write,
184};
185
186
187static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,
188 unsigned long *state)
189{
190 struct pwm_fan_ctx *ctx = cdev->devdata;
191
192 if (!ctx)
193 return -EINVAL;
194
195 *state = ctx->pwm_fan_max_state;
196
197 return 0;
198}
199
200static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,
201 unsigned long *state)
202{
203 struct pwm_fan_ctx *ctx = cdev->devdata;
204
205 if (!ctx)
206 return -EINVAL;
207
208 *state = ctx->pwm_fan_state;
209
210 return 0;
211}
212
213static int
214pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
215{
216 struct pwm_fan_ctx *ctx = cdev->devdata;
217 int ret;
218
219 if (!ctx || (state > ctx->pwm_fan_max_state))
220 return -EINVAL;
221
222 if (state == ctx->pwm_fan_state)
223 return 0;
224
225 ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
226 if (ret) {
227 dev_err(&cdev->device, "Cannot set pwm!\n");
228 return ret;
229 }
230
231 ctx->pwm_fan_state = state;
232
233 return ret;
234}
235
236static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
237 .get_max_state = pwm_fan_get_max_state,
238 .get_cur_state = pwm_fan_get_cur_state,
239 .set_cur_state = pwm_fan_set_cur_state,
240};
241
242static int pwm_fan_of_get_cooling_data(struct device *dev,
243 struct pwm_fan_ctx *ctx)
244{
245 struct device_node *np = dev->of_node;
246 int num, i, ret;
247
248 if (!of_find_property(np, "cooling-levels", NULL))
249 return 0;
250
251 ret = of_property_count_u32_elems(np, "cooling-levels");
252 if (ret <= 0) {
253 dev_err(dev, "Wrong data!\n");
254 return ret ? : -EINVAL;
255 }
256
257 num = ret;
258 ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
259 GFP_KERNEL);
260 if (!ctx->pwm_fan_cooling_levels)
261 return -ENOMEM;
262
263 ret = of_property_read_u32_array(np, "cooling-levels",
264 ctx->pwm_fan_cooling_levels, num);
265 if (ret) {
266 dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
267 return ret;
268 }
269
270 for (i = 0; i < num; i++) {
271 if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) {
272 dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
273 ctx->pwm_fan_cooling_levels[i], MAX_PWM);
274 return -EINVAL;
275 }
276 }
277
278 ctx->pwm_fan_max_state = num - 1;
279
280 return 0;
281}
282
283static void pwm_fan_regulator_disable(void *data)
284{
285 regulator_disable(data);
286}
287
288static void pwm_fan_pwm_disable(void *__ctx)
289{
290 struct pwm_fan_ctx *ctx = __ctx;
291
292 ctx->pwm_state.enabled = false;
293 pwm_apply_state(ctx->pwm, &ctx->pwm_state);
294 del_timer_sync(&ctx->rpm_timer);
295}
296
297static int pwm_fan_probe(struct platform_device *pdev)
298{
299 struct thermal_cooling_device *cdev;
300 struct device *dev = &pdev->dev;
301 struct pwm_fan_ctx *ctx;
302 struct device *hwmon;
303 int ret;
304 const struct hwmon_channel_info **channels;
305 u32 *fan_channel_config;
306 int channel_count = 1;
307 int i;
308
309 ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
310 if (!ctx)
311 return -ENOMEM;
312
313 mutex_init(&ctx->lock);
314
315 ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL);
316 if (IS_ERR(ctx->pwm))
317 return dev_err_probe(dev, PTR_ERR(ctx->pwm), "Could not get PWM\n");
318
319 platform_set_drvdata(pdev, ctx);
320
321 ctx->reg_en = devm_regulator_get_optional(dev, "fan");
322 if (IS_ERR(ctx->reg_en)) {
323 if (PTR_ERR(ctx->reg_en) != -ENODEV)
324 return PTR_ERR(ctx->reg_en);
325
326 ctx->reg_en = NULL;
327 } else {
328 ret = regulator_enable(ctx->reg_en);
329 if (ret) {
330 dev_err(dev, "Failed to enable fan supply: %d\n", ret);
331 return ret;
332 }
333 ret = devm_add_action_or_reset(dev, pwm_fan_regulator_disable,
334 ctx->reg_en);
335 if (ret)
336 return ret;
337 }
338
339 pwm_init_state(ctx->pwm, &ctx->pwm_state);
340
341
342
343
344
345
346 if (ctx->pwm_state.period > ULONG_MAX / MAX_PWM + 1) {
347 dev_err(dev, "Configured period too big\n");
348 return -EINVAL;
349 }
350
351
352 ret = __set_pwm(ctx, MAX_PWM);
353 if (ret) {
354 dev_err(dev, "Failed to configure PWM: %d\n", ret);
355 return ret;
356 }
357 timer_setup(&ctx->rpm_timer, sample_timer, 0);
358 ret = devm_add_action_or_reset(dev, pwm_fan_pwm_disable, ctx);
359 if (ret)
360 return ret;
361
362 ctx->tach_count = platform_irq_count(pdev);
363 if (ctx->tach_count < 0)
364 return dev_err_probe(dev, ctx->tach_count,
365 "Could not get number of fan tachometer inputs\n");
366 dev_dbg(dev, "%d fan tachometer inputs\n", ctx->tach_count);
367
368 if (ctx->tach_count) {
369 channel_count++;
370
371 ctx->tachs = devm_kcalloc(dev, ctx->tach_count,
372 sizeof(struct pwm_fan_tach),
373 GFP_KERNEL);
374 if (!ctx->tachs)
375 return -ENOMEM;
376
377 ctx->fan_channel.type = hwmon_fan;
378 fan_channel_config = devm_kcalloc(dev, ctx->tach_count + 1,
379 sizeof(u32), GFP_KERNEL);
380 if (!fan_channel_config)
381 return -ENOMEM;
382 ctx->fan_channel.config = fan_channel_config;
383 }
384
385 channels = devm_kcalloc(dev, channel_count + 1,
386 sizeof(struct hwmon_channel_info *), GFP_KERNEL);
387 if (!channels)
388 return -ENOMEM;
389
390 channels[0] = &pwm_fan_channel_pwm;
391
392 for (i = 0; i < ctx->tach_count; i++) {
393 struct pwm_fan_tach *tach = &ctx->tachs[i];
394 u32 ppr = 2;
395
396 tach->irq = platform_get_irq(pdev, i);
397 if (tach->irq == -EPROBE_DEFER)
398 return tach->irq;
399 if (tach->irq > 0) {
400 ret = devm_request_irq(dev, tach->irq, pulse_handler, 0,
401 pdev->name, tach);
402 if (ret) {
403 dev_err(dev,
404 "Failed to request interrupt: %d\n",
405 ret);
406 return ret;
407 }
408 }
409
410 of_property_read_u32_index(dev->of_node,
411 "pulses-per-revolution",
412 i,
413 &ppr);
414 tach->pulses_per_revolution = ppr;
415 if (!tach->pulses_per_revolution) {
416 dev_err(dev, "pulses-per-revolution can't be zero.\n");
417 return -EINVAL;
418 }
419
420 fan_channel_config[i] = HWMON_F_INPUT;
421
422 dev_dbg(dev, "tach%d: irq=%d, pulses_per_revolution=%d\n",
423 i, tach->irq, tach->pulses_per_revolution);
424 }
425
426 if (ctx->tach_count > 0) {
427 ctx->sample_start = ktime_get();
428 mod_timer(&ctx->rpm_timer, jiffies + HZ);
429
430 channels[1] = &ctx->fan_channel;
431 }
432
433 ctx->info.ops = &pwm_fan_hwmon_ops;
434 ctx->info.info = channels;
435
436 hwmon = devm_hwmon_device_register_with_info(dev, "pwmfan",
437 ctx, &ctx->info, NULL);
438 if (IS_ERR(hwmon)) {
439 dev_err(dev, "Failed to register hwmon device\n");
440 return PTR_ERR(hwmon);
441 }
442
443 ret = pwm_fan_of_get_cooling_data(dev, ctx);
444 if (ret)
445 return ret;
446
447 ctx->pwm_fan_state = ctx->pwm_fan_max_state;
448 if (IS_ENABLED(CONFIG_THERMAL)) {
449 cdev = devm_thermal_of_cooling_device_register(dev,
450 dev->of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops);
451 if (IS_ERR(cdev)) {
452 ret = PTR_ERR(cdev);
453 dev_err(dev,
454 "Failed to register pwm-fan as cooling device: %d\n",
455 ret);
456 return ret;
457 }
458 ctx->cdev = cdev;
459 }
460
461 return 0;
462}
463
464static int pwm_fan_disable(struct device *dev)
465{
466 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
467 int ret;
468
469 if (ctx->pwm_value) {
470
471 struct pwm_state state = ctx->pwm_state;
472
473 state.duty_cycle = 0;
474 state.enabled = false;
475 ret = pwm_apply_state(ctx->pwm, &state);
476 if (ret < 0)
477 return ret;
478 }
479
480 if (ctx->reg_en) {
481 ret = regulator_disable(ctx->reg_en);
482 if (ret) {
483 dev_err(dev, "Failed to disable fan supply: %d\n", ret);
484 return ret;
485 }
486 }
487
488 return 0;
489}
490
491static void pwm_fan_shutdown(struct platform_device *pdev)
492{
493 pwm_fan_disable(&pdev->dev);
494}
495
496#ifdef CONFIG_PM_SLEEP
497static int pwm_fan_suspend(struct device *dev)
498{
499 return pwm_fan_disable(dev);
500}
501
502static int pwm_fan_resume(struct device *dev)
503{
504 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
505 int ret;
506
507 if (ctx->reg_en) {
508 ret = regulator_enable(ctx->reg_en);
509 if (ret) {
510 dev_err(dev, "Failed to enable fan supply: %d\n", ret);
511 return ret;
512 }
513 }
514
515 if (ctx->pwm_value == 0)
516 return 0;
517
518 return pwm_apply_state(ctx->pwm, &ctx->pwm_state);
519}
520#endif
521
522static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
523
524static const struct of_device_id of_pwm_fan_match[] = {
525 { .compatible = "pwm-fan", },
526 {},
527};
528MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
529
530static struct platform_driver pwm_fan_driver = {
531 .probe = pwm_fan_probe,
532 .shutdown = pwm_fan_shutdown,
533 .driver = {
534 .name = "pwm-fan",
535 .pm = &pwm_fan_pm,
536 .of_match_table = of_pwm_fan_match,
537 },
538};
539
540module_platform_driver(pwm_fan_driver);
541
542MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
543MODULE_ALIAS("platform:pwm-fan");
544MODULE_DESCRIPTION("PWM FAN driver");
545MODULE_LICENSE("GPL");
546
