treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
[sfrench/cifs-2.6.git] / drivers / hwmon / pwm-fan.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * pwm-fan.c - Hwmon driver for fans connected to PWM lines.
4  *
5  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
6  *
7  * Author: Kamil Debski <k.debski@samsung.com>
8  */
9
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
25 struct 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 /* This handler assumes self resetting edge triggered interrupt. */
45 static 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
54 static 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
70 static 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;
88 exit_set_pwm_err:
89         mutex_unlock(&ctx->lock);
90         return ret;
91 }
92
93 static 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
104 static 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
122 static 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
130 static 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
138 static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0);
139 static SENSOR_DEVICE_ATTR_RO(fan1_input, rpm, 0);
140
141 static 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
147 static 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         /* Hide fan_input in case no interrupt is available  */
154         if (n == 1 && ctx->irq <= 0)
155                 return 0;
156
157         return a->mode;
158 }
159
160 static const struct attribute_group pwm_fan_group = {
161         .attrs = pwm_fan_attrs,
162         .is_visible = pwm_fan_attrs_visible,
163 };
164
165 static const struct attribute_group *pwm_fan_groups[] = {
166         &pwm_fan_group,
167         NULL,
168 };
169
170 /* thermal cooling device callbacks */
171 static 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
184 static 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
197 static int
198 pwm_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
220 static 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
226 static 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
267 static void pwm_fan_regulator_disable(void *data)
268 {
269         regulator_disable(data);
270 }
271
272 static 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
279 static 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(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                 devm_add_action_or_reset(dev, pwm_fan_regulator_disable,
324                                          ctx->reg_en);
325         }
326
327         ctx->pwm_value = MAX_PWM;
328
329         /* Set duty cycle to maximum allowed and enable PWM output */
330         pwm_init_state(ctx->pwm, &state);
331         state.duty_cycle = ctx->pwm->args.period - 1;
332         state.enabled = true;
333
334         ret = pwm_apply_state(ctx->pwm, &state);
335         if (ret) {
336                 dev_err(dev, "Failed to configure PWM: %d\n", ret);
337                 return ret;
338         }
339         timer_setup(&ctx->rpm_timer, sample_timer, 0);
340         devm_add_action_or_reset(dev, pwm_fan_pwm_disable, ctx);
341
342         of_property_read_u32(dev->of_node, "pulses-per-revolution", &ppr);
343         ctx->pulses_per_revolution = ppr;
344         if (!ctx->pulses_per_revolution) {
345                 dev_err(dev, "pulses-per-revolution can't be zero.\n");
346                 return -EINVAL;
347         }
348
349         if (ctx->irq > 0) {
350                 ret = devm_request_irq(dev, ctx->irq, pulse_handler, 0,
351                                        pdev->name, ctx);
352                 if (ret) {
353                         dev_err(dev, "Failed to request interrupt: %d\n", ret);
354                         return ret;
355                 }
356                 ctx->sample_start = ktime_get();
357                 mod_timer(&ctx->rpm_timer, jiffies + HZ);
358         }
359
360         hwmon = devm_hwmon_device_register_with_groups(dev, "pwmfan",
361                                                        ctx, pwm_fan_groups);
362         if (IS_ERR(hwmon)) {
363                 dev_err(dev, "Failed to register hwmon device\n");
364                 return PTR_ERR(hwmon);
365         }
366
367         ret = pwm_fan_of_get_cooling_data(dev, ctx);
368         if (ret)
369                 return ret;
370
371         ctx->pwm_fan_state = ctx->pwm_fan_max_state;
372         if (IS_ENABLED(CONFIG_THERMAL)) {
373                 cdev = devm_thermal_of_cooling_device_register(dev,
374                         dev->of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops);
375                 if (IS_ERR(cdev)) {
376                         ret = PTR_ERR(cdev);
377                         dev_err(dev,
378                                 "Failed to register pwm-fan as cooling device: %d\n",
379                                 ret);
380                         return ret;
381                 }
382                 ctx->cdev = cdev;
383                 thermal_cdev_update(cdev);
384         }
385
386         return 0;
387 }
388
389 #ifdef CONFIG_PM_SLEEP
390 static int pwm_fan_suspend(struct device *dev)
391 {
392         struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
393         struct pwm_args args;
394         int ret;
395
396         pwm_get_args(ctx->pwm, &args);
397
398         if (ctx->pwm_value) {
399                 ret = pwm_config(ctx->pwm, 0, args.period);
400                 if (ret < 0)
401                         return ret;
402
403                 pwm_disable(ctx->pwm);
404         }
405
406         if (ctx->reg_en) {
407                 ret = regulator_disable(ctx->reg_en);
408                 if (ret) {
409                         dev_err(dev, "Failed to disable fan supply: %d\n", ret);
410                         return ret;
411                 }
412         }
413
414         return 0;
415 }
416
417 static int pwm_fan_resume(struct device *dev)
418 {
419         struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
420         struct pwm_args pargs;
421         unsigned long duty;
422         int ret;
423
424         if (ctx->reg_en) {
425                 ret = regulator_enable(ctx->reg_en);
426                 if (ret) {
427                         dev_err(dev, "Failed to enable fan supply: %d\n", ret);
428                         return ret;
429                 }
430         }
431
432         if (ctx->pwm_value == 0)
433                 return 0;
434
435         pwm_get_args(ctx->pwm, &pargs);
436         duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
437         ret = pwm_config(ctx->pwm, duty, pargs.period);
438         if (ret)
439                 return ret;
440         return pwm_enable(ctx->pwm);
441 }
442 #endif
443
444 static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
445
446 static const struct of_device_id of_pwm_fan_match[] = {
447         { .compatible = "pwm-fan", },
448         {},
449 };
450 MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
451
452 static struct platform_driver pwm_fan_driver = {
453         .probe          = pwm_fan_probe,
454         .driver = {
455                 .name           = "pwm-fan",
456                 .pm             = &pwm_fan_pm,
457                 .of_match_table = of_pwm_fan_match,
458         },
459 };
460
461 module_platform_driver(pwm_fan_driver);
462
463 MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
464 MODULE_ALIAS("platform:pwm-fan");
465 MODULE_DESCRIPTION("PWM FAN driver");
466 MODULE_LICENSE("GPL");