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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_ctx {
25 struct mutex lock;
26 struct pwm_device *pwm;
27 struct regulator *reg_en;
28
29 int irq;
30 atomic_t pulses;
31 unsigned int rpm;
32 u8 pulses_per_revolution;
33 ktime_t sample_start;
34 struct timer_list rpm_timer;
35
36 unsigned int pwm_value;
37 unsigned int pwm_fan_state;
38 unsigned int pwm_fan_max_state;
39 unsigned int *pwm_fan_cooling_levels;
40 struct thermal_cooling_device *cdev;
41
42 struct hwmon_chip_info info;
43};
44
45static const u32 pwm_fan_channel_config_pwm[] = {
46 HWMON_PWM_INPUT,
47 0
48};
49
50static const struct hwmon_channel_info pwm_fan_channel_pwm = {
51 .type = hwmon_pwm,
52 .config = pwm_fan_channel_config_pwm,
53};
54
55static const u32 pwm_fan_channel_config_fan[] = {
56 HWMON_F_INPUT,
57 0
58};
59
60static const struct hwmon_channel_info pwm_fan_channel_fan = {
61 .type = hwmon_fan,
62 .config = pwm_fan_channel_config_fan,
63};
64
65
66static irqreturn_t pulse_handler(int irq, void *dev_id)
67{
68 struct pwm_fan_ctx *ctx = dev_id;
69
70 atomic_inc(&ctx->pulses);
71
72 return IRQ_HANDLED;
73}
74
75static void sample_timer(struct timer_list *t)
76{
77 struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
78 unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start);
79 int pulses;
80
81 if (delta) {
82 pulses = atomic_read(&ctx->pulses);
83 atomic_sub(pulses, &ctx->pulses);
84 ctx->rpm = (unsigned int)(pulses * 1000 * 60) /
85 (ctx->pulses_per_revolution * delta);
86
87 ctx->sample_start = ktime_get();
88 }
89
90 mod_timer(&ctx->rpm_timer, jiffies + HZ);
91}
92
93static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
94{
95 unsigned long period;
96 int ret = 0;
97 struct pwm_state state = { };
98
99 mutex_lock(&ctx->lock);
100 if (ctx->pwm_value == pwm)
101 goto exit_set_pwm_err;
102
103 pwm_init_state(ctx->pwm, &state);
104 period = ctx->pwm->args.period;
105 state.duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
106 state.enabled = pwm ? true : false;
107
108 ret = pwm_apply_state(ctx->pwm, &state);
109 if (!ret)
110 ctx->pwm_value = pwm;
111exit_set_pwm_err:
112 mutex_unlock(&ctx->lock);
113 return ret;
114}
115
116static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
117{
118 int i;
119
120 for (i = 0; i < ctx->pwm_fan_max_state; ++i)
121 if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
122 break;
123
124 ctx->pwm_fan_state = i;
125}
126
127static int pwm_fan_write(struct device *dev, enum hwmon_sensor_types type,
128 u32 attr, int channel, long val)
129{
130 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
131 int ret;
132
133 if (val < 0 || val > MAX_PWM)
134 return -EINVAL;
135
136 ret = __set_pwm(ctx, val);
137 if (ret)
138 return ret;
139
140 pwm_fan_update_state(ctx, val);
141 return 0;
142}
143
144static int pwm_fan_read(struct device *dev, enum hwmon_sensor_types type,
145 u32 attr, int channel, long *val)
146{
147 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
148
149 switch (type) {
150 case hwmon_pwm:
151 *val = ctx->pwm_value;
152 return 0;
153
154 case hwmon_fan:
155 *val = ctx->rpm;
156 return 0;
157
158 default:
159 return -ENOTSUPP;
160 }
161}
162
163static umode_t pwm_fan_is_visible(const void *data,
164 enum hwmon_sensor_types type,
165 u32 attr, int channel)
166{
167 switch (type) {
168 case hwmon_pwm:
169 return 0644;
170
171 case hwmon_fan:
172 return 0444;
173
174 default:
175 return 0;
176 }
177}
178
179static const struct hwmon_ops pwm_fan_hwmon_ops = {
180 .is_visible = pwm_fan_is_visible,
181 .read = pwm_fan_read,
182 .write = pwm_fan_write,
183};
184
185
186static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,
187 unsigned long *state)
188{
189 struct pwm_fan_ctx *ctx = cdev->devdata;
190
191 if (!ctx)
192 return -EINVAL;
193
194 *state = ctx->pwm_fan_max_state;
195
196 return 0;
197}
198
199static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,
200 unsigned long *state)
201{
202 struct pwm_fan_ctx *ctx = cdev->devdata;
203
204 if (!ctx)
205 return -EINVAL;
206
207 *state = ctx->pwm_fan_state;
208
209 return 0;
210}
211
212static int
213pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
214{
215 struct pwm_fan_ctx *ctx = cdev->devdata;
216 int ret;
217
218 if (!ctx || (state > ctx->pwm_fan_max_state))
219 return -EINVAL;
220
221 if (state == ctx->pwm_fan_state)
222 return 0;
223
224 ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
225 if (ret) {
226 dev_err(&cdev->device, "Cannot set pwm!\n");
227 return ret;
228 }
229
230 ctx->pwm_fan_state = state;
231
232 return ret;
233}
234
235static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
236 .get_max_state = pwm_fan_get_max_state,
237 .get_cur_state = pwm_fan_get_cur_state,
238 .set_cur_state = pwm_fan_set_cur_state,
239};
240
241static int pwm_fan_of_get_cooling_data(struct device *dev,
242 struct pwm_fan_ctx *ctx)
243{
244 struct device_node *np = dev->of_node;
245 int num, i, ret;
246
247 if (!of_find_property(np, "cooling-levels", NULL))
248 return 0;
249
250 ret = of_property_count_u32_elems(np, "cooling-levels");
251 if (ret <= 0) {
252 dev_err(dev, "Wrong data!\n");
253 return ret ? : -EINVAL;
254 }
255
256 num = ret;
257 ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
258 GFP_KERNEL);
259 if (!ctx->pwm_fan_cooling_levels)
260 return -ENOMEM;
261
262 ret = of_property_read_u32_array(np, "cooling-levels",
263 ctx->pwm_fan_cooling_levels, num);
264 if (ret) {
265 dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
266 return ret;
267 }
268
269 for (i = 0; i < num; i++) {
270 if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) {
271 dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
272 ctx->pwm_fan_cooling_levels[i], MAX_PWM);
273 return -EINVAL;
274 }
275 }
276
277 ctx->pwm_fan_max_state = num - 1;
278
279 return 0;
280}
281
282static void pwm_fan_regulator_disable(void *data)
283{
284 regulator_disable(data);
285}
286
287static void pwm_fan_pwm_disable(void *__ctx)
288{
289 struct pwm_fan_ctx *ctx = __ctx;
290 pwm_disable(ctx->pwm);
291 del_timer_sync(&ctx->rpm_timer);
292}
293
294static int pwm_fan_probe(struct platform_device *pdev)
295{
296 struct thermal_cooling_device *cdev;
297 struct device *dev = &pdev->dev;
298 struct pwm_fan_ctx *ctx;
299 struct device *hwmon;
300 int ret;
301 struct pwm_state state = { };
302 int tach_count;
303 const struct hwmon_channel_info **channels;
304
305 ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
306 if (!ctx)
307 return -ENOMEM;
308
309 mutex_init(&ctx->lock);
310
311 ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL);
312 if (IS_ERR(ctx->pwm))
313 return dev_err_probe(dev, PTR_ERR(ctx->pwm), "Could not get PWM\n");
314
315 platform_set_drvdata(pdev, ctx);
316
317 ctx->reg_en = devm_regulator_get_optional(dev, "fan");
318 if (IS_ERR(ctx->reg_en)) {
319 if (PTR_ERR(ctx->reg_en) != -ENODEV)
320 return PTR_ERR(ctx->reg_en);
321
322 ctx->reg_en = NULL;
323 } else {
324 ret = regulator_enable(ctx->reg_en);
325 if (ret) {
326 dev_err(dev, "Failed to enable fan supply: %d\n", ret);
327 return ret;
328 }
329 ret = devm_add_action_or_reset(dev, pwm_fan_regulator_disable,
330 ctx->reg_en);
331 if (ret)
332 return ret;
333 }
334
335 ctx->pwm_value = MAX_PWM;
336
337 pwm_init_state(ctx->pwm, &state);
338
339
340
341
342
343 if (state.period > ULONG_MAX / MAX_PWM + 1) {
344 dev_err(dev, "Configured period too big\n");
345 return -EINVAL;
346 }
347
348
349 state.duty_cycle = ctx->pwm->args.period - 1;
350 state.enabled = true;
351
352 ret = pwm_apply_state(ctx->pwm, &state);
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 tach_count = platform_irq_count(pdev);
363 if (tach_count < 0)
364 return dev_err_probe(dev, tach_count,
365 "Could not get number of fan tachometer inputs\n");
366
367 channels = devm_kcalloc(dev, tach_count + 2,
368 sizeof(struct hwmon_channel_info *), GFP_KERNEL);
369 if (!channels)
370 return -ENOMEM;
371
372 channels[0] = &pwm_fan_channel_pwm;
373
374 if (tach_count > 0) {
375 u32 ppr = 2;
376
377 ctx->irq = platform_get_irq(pdev, 0);
378 if (ctx->irq == -EPROBE_DEFER)
379 return ctx->irq;
380 if (ctx->irq > 0) {
381 ret = devm_request_irq(dev, ctx->irq, pulse_handler, 0,
382 pdev->name, ctx);
383 if (ret) {
384 dev_err(dev,
385 "Failed to request interrupt: %d\n",
386 ret);
387 return ret;
388 }
389 }
390
391 of_property_read_u32(dev->of_node,
392 "pulses-per-revolution",
393 &ppr);
394 ctx->pulses_per_revolution = ppr;
395 if (!ctx->pulses_per_revolution) {
396 dev_err(dev, "pulses-per-revolution can't be zero.\n");
397 return -EINVAL;
398 }
399
400 dev_dbg(dev, "tach: irq=%d, pulses_per_revolution=%d\n",
401 ctx->irq, ctx->pulses_per_revolution);
402
403 ctx->sample_start = ktime_get();
404 mod_timer(&ctx->rpm_timer, jiffies + HZ);
405
406 channels[1] = &pwm_fan_channel_fan;
407 }
408
409 ctx->info.ops = &pwm_fan_hwmon_ops;
410 ctx->info.info = channels;
411
412 hwmon = devm_hwmon_device_register_with_info(dev, "pwmfan",
413 ctx, &ctx->info, NULL);
414 if (IS_ERR(hwmon)) {
415 dev_err(dev, "Failed to register hwmon device\n");
416 return PTR_ERR(hwmon);
417 }
418
419 ret = pwm_fan_of_get_cooling_data(dev, ctx);
420 if (ret)
421 return ret;
422
423 ctx->pwm_fan_state = ctx->pwm_fan_max_state;
424 if (IS_ENABLED(CONFIG_THERMAL)) {
425 cdev = devm_thermal_of_cooling_device_register(dev,
426 dev->of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops);
427 if (IS_ERR(cdev)) {
428 ret = PTR_ERR(cdev);
429 dev_err(dev,
430 "Failed to register pwm-fan as cooling device: %d\n",
431 ret);
432 return ret;
433 }
434 ctx->cdev = cdev;
435 thermal_cdev_update(cdev);
436 }
437
438 return 0;
439}
440
441static int pwm_fan_disable(struct device *dev)
442{
443 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
444 struct pwm_args args;
445 int ret;
446
447 pwm_get_args(ctx->pwm, &args);
448
449 if (ctx->pwm_value) {
450 ret = pwm_config(ctx->pwm, 0, args.period);
451 if (ret < 0)
452 return ret;
453
454 pwm_disable(ctx->pwm);
455 }
456
457 if (ctx->reg_en) {
458 ret = regulator_disable(ctx->reg_en);
459 if (ret) {
460 dev_err(dev, "Failed to disable fan supply: %d\n", ret);
461 return ret;
462 }
463 }
464
465 return 0;
466}
467
468static void pwm_fan_shutdown(struct platform_device *pdev)
469{
470 pwm_fan_disable(&pdev->dev);
471}
472
473#ifdef CONFIG_PM_SLEEP
474static int pwm_fan_suspend(struct device *dev)
475{
476 return pwm_fan_disable(dev);
477}
478
479static int pwm_fan_resume(struct device *dev)
480{
481 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
482 struct pwm_args pargs;
483 unsigned long duty;
484 int ret;
485
486 if (ctx->reg_en) {
487 ret = regulator_enable(ctx->reg_en);
488 if (ret) {
489 dev_err(dev, "Failed to enable fan supply: %d\n", ret);
490 return ret;
491 }
492 }
493
494 if (ctx->pwm_value == 0)
495 return 0;
496
497 pwm_get_args(ctx->pwm, &pargs);
498 duty = DIV_ROUND_UP_ULL(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
499 ret = pwm_config(ctx->pwm, duty, pargs.period);
500 if (ret)
501 return ret;
502 return pwm_enable(ctx->pwm);
503}
504#endif
505
506static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
507
508static const struct of_device_id of_pwm_fan_match[] = {
509 { .compatible = "pwm-fan", },
510 {},
511};
512MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
513
514static struct platform_driver pwm_fan_driver = {
515 .probe = pwm_fan_probe,
516 .shutdown = pwm_fan_shutdown,
517 .driver = {
518 .name = "pwm-fan",
519 .pm = &pwm_fan_pm,
520 .of_match_table = of_pwm_fan_match,
521 },
522};
523
524module_platform_driver(pwm_fan_driver);
525
526MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
527MODULE_ALIAS("platform:pwm-fan");
528MODULE_DESCRIPTION("PWM FAN driver");
529MODULE_LICENSE("GPL");
530
