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10#include <linux/hwmon.h>
11#include <linux/hwmon-sysfs.h>
12#include <linux/interrupt.h>
13#include <linux/module.h>
14#include <linux/mutex.h>
15#include <linux/of.h>
16#include <linux/platform_device.h>
17#include <linux/pwm.h>
18#include <linux/regulator/consumer.h>
19#include <linux/sysfs.h>
20#include <linux/thermal.h>
21#include <linux/timer.h>
22
23#define MAX_PWM 255
24
25struct pwm_fan_ctx {
26 struct mutex lock;
27 struct pwm_device *pwm;
28 struct regulator *reg_en;
29
30 int irq;
31 atomic_t pulses;
32 unsigned int rpm;
33 u8 pulses_per_revolution;
34 ktime_t sample_start;
35 struct timer_list rpm_timer;
36
37 unsigned int pwm_value;
38 unsigned int pwm_fan_state;
39 unsigned int pwm_fan_max_state;
40 unsigned int *pwm_fan_cooling_levels;
41 struct thermal_cooling_device *cdev;
42};
43
44
45static irqreturn_t pulse_handler(int irq, void *dev_id)
46{
47 struct pwm_fan_ctx *ctx = dev_id;
48
49 atomic_inc(&ctx->pulses);
50
51 return IRQ_HANDLED;
52}
53
54static void sample_timer(struct timer_list *t)
55{
56 struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
57 int pulses;
58 u64 tmp;
59
60 pulses = atomic_read(&ctx->pulses);
61 atomic_sub(pulses, &ctx->pulses);
62 tmp = (u64)pulses * ktime_ms_delta(ktime_get(), ctx->sample_start) * 60;
63 do_div(tmp, ctx->pulses_per_revolution * 1000);
64 ctx->rpm = tmp;
65
66 ctx->sample_start = ktime_get();
67 mod_timer(&ctx->rpm_timer, jiffies + HZ);
68}
69
70static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
71{
72 unsigned long period;
73 int ret = 0;
74 struct pwm_state state = { };
75
76 mutex_lock(&ctx->lock);
77 if (ctx->pwm_value == pwm)
78 goto exit_set_pwm_err;
79
80 pwm_init_state(ctx->pwm, &state);
81 period = ctx->pwm->args.period;
82 state.duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
83 state.enabled = pwm ? true : false;
84
85 ret = pwm_apply_state(ctx->pwm, &state);
86 if (!ret)
87 ctx->pwm_value = pwm;
88exit_set_pwm_err:
89 mutex_unlock(&ctx->lock);
90 return ret;
91}
92
93static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
94{
95 int i;
96
97 for (i = 0; i < ctx->pwm_fan_max_state; ++i)
98 if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
99 break;
100
101 ctx->pwm_fan_state = i;
102}
103
104static ssize_t pwm_store(struct device *dev, struct device_attribute *attr,
105 const char *buf, size_t count)
106{
107 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
108 unsigned long pwm;
109 int ret;
110
111 if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM)
112 return -EINVAL;
113
114 ret = __set_pwm(ctx, pwm);
115 if (ret)
116 return ret;
117
118 pwm_fan_update_state(ctx, pwm);
119 return count;
120}
121
122static ssize_t pwm_show(struct device *dev, struct device_attribute *attr,
123 char *buf)
124{
125 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
126
127 return sprintf(buf, "%u\n", ctx->pwm_value);
128}
129
130static ssize_t rpm_show(struct device *dev,
131 struct device_attribute *attr, char *buf)
132{
133 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
134
135 return sprintf(buf, "%u\n", ctx->rpm);
136}
137
138static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0);
139static SENSOR_DEVICE_ATTR_RO(fan1_input, rpm, 0);
140
141static struct attribute *pwm_fan_attrs[] = {
142 &sensor_dev_attr_pwm1.dev_attr.attr,
143 &sensor_dev_attr_fan1_input.dev_attr.attr,
144 NULL,
145};
146
147static umode_t pwm_fan_attrs_visible(struct kobject *kobj, struct attribute *a,
148 int n)
149{
150 struct device *dev = container_of(kobj, struct device, kobj);
151 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
152
153
154 if (n == 1 && ctx->irq <= 0)
155 return 0;
156
157 return a->mode;
158}
159
160static const struct attribute_group pwm_fan_group = {
161 .attrs = pwm_fan_attrs,
162 .is_visible = pwm_fan_attrs_visible,
163};
164
165static const struct attribute_group *pwm_fan_groups[] = {
166 &pwm_fan_group,
167 NULL,
168};
169
170
171static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,
172 unsigned long *state)
173{
174 struct pwm_fan_ctx *ctx = cdev->devdata;
175
176 if (!ctx)
177 return -EINVAL;
178
179 *state = ctx->pwm_fan_max_state;
180
181 return 0;
182}
183
184static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,
185 unsigned long *state)
186{
187 struct pwm_fan_ctx *ctx = cdev->devdata;
188
189 if (!ctx)
190 return -EINVAL;
191
192 *state = ctx->pwm_fan_state;
193
194 return 0;
195}
196
197static int
198pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
199{
200 struct pwm_fan_ctx *ctx = cdev->devdata;
201 int ret;
202
203 if (!ctx || (state > ctx->pwm_fan_max_state))
204 return -EINVAL;
205
206 if (state == ctx->pwm_fan_state)
207 return 0;
208
209 ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
210 if (ret) {
211 dev_err(&cdev->device, "Cannot set pwm!\n");
212 return ret;
213 }
214
215 ctx->pwm_fan_state = state;
216
217 return ret;
218}
219
220static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
221 .get_max_state = pwm_fan_get_max_state,
222 .get_cur_state = pwm_fan_get_cur_state,
223 .set_cur_state = pwm_fan_set_cur_state,
224};
225
226static int pwm_fan_of_get_cooling_data(struct device *dev,
227 struct pwm_fan_ctx *ctx)
228{
229 struct device_node *np = dev->of_node;
230 int num, i, ret;
231
232 if (!of_find_property(np, "cooling-levels", NULL))
233 return 0;
234
235 ret = of_property_count_u32_elems(np, "cooling-levels");
236 if (ret <= 0) {
237 dev_err(dev, "Wrong data!\n");
238 return ret ? : -EINVAL;
239 }
240
241 num = ret;
242 ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
243 GFP_KERNEL);
244 if (!ctx->pwm_fan_cooling_levels)
245 return -ENOMEM;
246
247 ret = of_property_read_u32_array(np, "cooling-levels",
248 ctx->pwm_fan_cooling_levels, num);
249 if (ret) {
250 dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
251 return ret;
252 }
253
254 for (i = 0; i < num; i++) {
255 if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) {
256 dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
257 ctx->pwm_fan_cooling_levels[i], MAX_PWM);
258 return -EINVAL;
259 }
260 }
261
262 ctx->pwm_fan_max_state = num - 1;
263
264 return 0;
265}
266
267static void pwm_fan_regulator_disable(void *data)
268{
269 regulator_disable(data);
270}
271
272static void pwm_fan_pwm_disable(void *__ctx)
273{
274 struct pwm_fan_ctx *ctx = __ctx;
275 pwm_disable(ctx->pwm);
276 del_timer_sync(&ctx->rpm_timer);
277}
278
279static int pwm_fan_probe(struct platform_device *pdev)
280{
281 struct thermal_cooling_device *cdev;
282 struct device *dev = &pdev->dev;
283 struct pwm_fan_ctx *ctx;
284 struct device *hwmon;
285 int ret;
286 struct pwm_state state = { };
287 u32 ppr = 2;
288
289 ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
290 if (!ctx)
291 return -ENOMEM;
292
293 mutex_init(&ctx->lock);
294
295 ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL);
296 if (IS_ERR(ctx->pwm)) {
297 ret = PTR_ERR(ctx->pwm);
298
299 if (ret != -EPROBE_DEFER)
300 dev_err(dev, "Could not get PWM: %d\n", ret);
301
302 return ret;
303 }
304
305 platform_set_drvdata(pdev, ctx);
306
307 ctx->irq = platform_get_irq_optional(pdev, 0);
308 if (ctx->irq == -EPROBE_DEFER)
309 return ctx->irq;
310
311 ctx->reg_en = devm_regulator_get_optional(dev, "fan");
312 if (IS_ERR(ctx->reg_en)) {
313 if (PTR_ERR(ctx->reg_en) != -ENODEV)
314 return PTR_ERR(ctx->reg_en);
315
316 ctx->reg_en = NULL;
317 } else {
318 ret = regulator_enable(ctx->reg_en);
319 if (ret) {
320 dev_err(dev, "Failed to enable fan supply: %d\n", ret);
321 return ret;
322 }
323 ret = devm_add_action_or_reset(dev, pwm_fan_regulator_disable,
324 ctx->reg_en);
325 if (ret)
326 return ret;
327 }
328
329 ctx->pwm_value = MAX_PWM;
330
331
332 pwm_init_state(ctx->pwm, &state);
333 state.duty_cycle = ctx->pwm->args.period - 1;
334 state.enabled = true;
335
336 ret = pwm_apply_state(ctx->pwm, &state);
337 if (ret) {
338 dev_err(dev, "Failed to configure PWM: %d\n", ret);
339 return ret;
340 }
341 timer_setup(&ctx->rpm_timer, sample_timer, 0);
342 ret = devm_add_action_or_reset(dev, pwm_fan_pwm_disable, ctx);
343 if (ret)
344 return ret;
345
346 of_property_read_u32(dev->of_node, "pulses-per-revolution", &ppr);
347 ctx->pulses_per_revolution = ppr;
348 if (!ctx->pulses_per_revolution) {
349 dev_err(dev, "pulses-per-revolution can't be zero.\n");
350 return -EINVAL;
351 }
352
353 if (ctx->irq > 0) {
354 ret = devm_request_irq(dev, ctx->irq, pulse_handler, 0,
355 pdev->name, ctx);
356 if (ret) {
357 dev_err(dev, "Failed to request interrupt: %d\n", ret);
358 return ret;
359 }
360 ctx->sample_start = ktime_get();
361 mod_timer(&ctx->rpm_timer, jiffies + HZ);
362 }
363
364 hwmon = devm_hwmon_device_register_with_groups(dev, "pwmfan",
365 ctx, pwm_fan_groups);
366 if (IS_ERR(hwmon)) {
367 dev_err(dev, "Failed to register hwmon device\n");
368 return PTR_ERR(hwmon);
369 }
370
371 ret = pwm_fan_of_get_cooling_data(dev, ctx);
372 if (ret)
373 return ret;
374
375 ctx->pwm_fan_state = ctx->pwm_fan_max_state;
376 if (IS_ENABLED(CONFIG_THERMAL)) {
377 cdev = devm_thermal_of_cooling_device_register(dev,
378 dev->of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops);
379 if (IS_ERR(cdev)) {
380 ret = PTR_ERR(cdev);
381 dev_err(dev,
382 "Failed to register pwm-fan as cooling device: %d\n",
383 ret);
384 return ret;
385 }
386 ctx->cdev = cdev;
387 thermal_cdev_update(cdev);
388 }
389
390 return 0;
391}
392
393#ifdef CONFIG_PM_SLEEP
394static int pwm_fan_suspend(struct device *dev)
395{
396 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
397 struct pwm_args args;
398 int ret;
399
400 pwm_get_args(ctx->pwm, &args);
401
402 if (ctx->pwm_value) {
403 ret = pwm_config(ctx->pwm, 0, args.period);
404 if (ret < 0)
405 return ret;
406
407 pwm_disable(ctx->pwm);
408 }
409
410 if (ctx->reg_en) {
411 ret = regulator_disable(ctx->reg_en);
412 if (ret) {
413 dev_err(dev, "Failed to disable fan supply: %d\n", ret);
414 return ret;
415 }
416 }
417
418 return 0;
419}
420
421static int pwm_fan_resume(struct device *dev)
422{
423 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
424 struct pwm_args pargs;
425 unsigned long duty;
426 int ret;
427
428 if (ctx->reg_en) {
429 ret = regulator_enable(ctx->reg_en);
430 if (ret) {
431 dev_err(dev, "Failed to enable fan supply: %d\n", ret);
432 return ret;
433 }
434 }
435
436 if (ctx->pwm_value == 0)
437 return 0;
438
439 pwm_get_args(ctx->pwm, &pargs);
440 duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
441 ret = pwm_config(ctx->pwm, duty, pargs.period);
442 if (ret)
443 return ret;
444 return pwm_enable(ctx->pwm);
445}
446#endif
447
448static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
449
450static const struct of_device_id of_pwm_fan_match[] = {
451 { .compatible = "pwm-fan", },
452 {},
453};
454MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
455
456static struct platform_driver pwm_fan_driver = {
457 .probe = pwm_fan_probe,
458 .driver = {
459 .name = "pwm-fan",
460 .pm = &pwm_fan_pm,
461 .of_match_table = of_pwm_fan_match,
462 },
463};
464
465module_platform_driver(pwm_fan_driver);
466
467MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
468MODULE_ALIAS("platform:pwm-fan");
469MODULE_DESCRIPTION("PWM FAN driver");
470MODULE_LICENSE("GPL");
471
