1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * pwm-fan.c - Hwmon driver for fans connected to PWM lines.
5 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
7 * Author: Kamil Debski <k.debski@samsung.com>
10 #include <linux/hwmon.h>
11 #include <linux/interrupt.h>
12 #include <linux/module.h>
13 #include <linux/mutex.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>
26 struct pwm_device *pwm;
27 struct regulator *reg_en;
32 u8 pulses_per_revolution;
34 struct timer_list rpm_timer;
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;
42 struct hwmon_chip_info info;
45 static const u32 pwm_fan_channel_config_pwm[] = {
50 static const struct hwmon_channel_info pwm_fan_channel_pwm = {
52 .config = pwm_fan_channel_config_pwm,
55 static const u32 pwm_fan_channel_config_fan[] = {
60 static const struct hwmon_channel_info pwm_fan_channel_fan = {
62 .config = pwm_fan_channel_config_fan,
65 /* This handler assumes self resetting edge triggered interrupt. */
66 static irqreturn_t pulse_handler(int irq, void *dev_id)
68 struct pwm_fan_ctx *ctx = dev_id;
70 atomic_inc(&ctx->pulses);
75 static void sample_timer(struct timer_list *t)
77 struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
78 unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start);
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);
87 ctx->sample_start = ktime_get();
90 mod_timer(&ctx->rpm_timer, jiffies + HZ);
93 static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
97 struct pwm_state state = { };
99 mutex_lock(&ctx->lock);
100 if (ctx->pwm_value == pwm)
101 goto exit_set_pwm_err;
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;
108 ret = pwm_apply_state(ctx->pwm, &state);
110 ctx->pwm_value = pwm;
112 mutex_unlock(&ctx->lock);
116 static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm)
120 for (i = 0; i < ctx->pwm_fan_max_state; ++i)
121 if (pwm < ctx->pwm_fan_cooling_levels[i + 1])
124 ctx->pwm_fan_state = i;
127 static int pwm_fan_write(struct device *dev, enum hwmon_sensor_types type,
128 u32 attr, int channel, long val)
130 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
133 if (val < 0 || val > MAX_PWM)
136 ret = __set_pwm(ctx, val);
140 pwm_fan_update_state(ctx, val);
144 static int pwm_fan_read(struct device *dev, enum hwmon_sensor_types type,
145 u32 attr, int channel, long *val)
147 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
151 *val = ctx->pwm_value;
163 static umode_t pwm_fan_is_visible(const void *data,
164 enum hwmon_sensor_types type,
165 u32 attr, int channel)
179 static 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,
185 /* thermal cooling device callbacks */
186 static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev,
187 unsigned long *state)
189 struct pwm_fan_ctx *ctx = cdev->devdata;
194 *state = ctx->pwm_fan_max_state;
199 static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev,
200 unsigned long *state)
202 struct pwm_fan_ctx *ctx = cdev->devdata;
207 *state = ctx->pwm_fan_state;
213 pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
215 struct pwm_fan_ctx *ctx = cdev->devdata;
218 if (!ctx || (state > ctx->pwm_fan_max_state))
221 if (state == ctx->pwm_fan_state)
224 ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
226 dev_err(&cdev->device, "Cannot set pwm!\n");
230 ctx->pwm_fan_state = state;
235 static 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,
241 static int pwm_fan_of_get_cooling_data(struct device *dev,
242 struct pwm_fan_ctx *ctx)
244 struct device_node *np = dev->of_node;
247 if (!of_find_property(np, "cooling-levels", NULL))
250 ret = of_property_count_u32_elems(np, "cooling-levels");
252 dev_err(dev, "Wrong data!\n");
253 return ret ? : -EINVAL;
257 ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32),
259 if (!ctx->pwm_fan_cooling_levels)
262 ret = of_property_read_u32_array(np, "cooling-levels",
263 ctx->pwm_fan_cooling_levels, num);
265 dev_err(dev, "Property 'cooling-levels' cannot be read!\n");
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);
277 ctx->pwm_fan_max_state = num - 1;
282 static void pwm_fan_regulator_disable(void *data)
284 regulator_disable(data);
287 static void pwm_fan_pwm_disable(void *__ctx)
289 struct pwm_fan_ctx *ctx = __ctx;
290 pwm_disable(ctx->pwm);
291 del_timer_sync(&ctx->rpm_timer);
294 static int pwm_fan_probe(struct platform_device *pdev)
296 struct thermal_cooling_device *cdev;
297 struct device *dev = &pdev->dev;
298 struct pwm_fan_ctx *ctx;
299 struct device *hwmon;
301 struct pwm_state state = { };
303 const struct hwmon_channel_info **channels;
305 ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
309 mutex_init(&ctx->lock);
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");
315 platform_set_drvdata(pdev, ctx);
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);
324 ret = regulator_enable(ctx->reg_en);
326 dev_err(dev, "Failed to enable fan supply: %d\n", ret);
329 ret = devm_add_action_or_reset(dev, pwm_fan_regulator_disable,
335 ctx->pwm_value = MAX_PWM;
337 pwm_init_state(ctx->pwm, &state);
339 * __set_pwm assumes that MAX_PWM * (period - 1) fits into an unsigned
340 * long. Check this here to prevent the fan running at a too low
343 if (state.period > ULONG_MAX / MAX_PWM + 1) {
344 dev_err(dev, "Configured period too big\n");
348 /* Set duty cycle to maximum allowed and enable PWM output */
349 state.duty_cycle = ctx->pwm->args.period - 1;
350 state.enabled = true;
352 ret = pwm_apply_state(ctx->pwm, &state);
354 dev_err(dev, "Failed to configure PWM: %d\n", ret);
357 timer_setup(&ctx->rpm_timer, sample_timer, 0);
358 ret = devm_add_action_or_reset(dev, pwm_fan_pwm_disable, ctx);
362 tach_count = platform_irq_count(pdev);
364 return dev_err_probe(dev, tach_count,
365 "Could not get number of fan tachometer inputs\n");
367 channels = devm_kcalloc(dev, tach_count + 2,
368 sizeof(struct hwmon_channel_info *), GFP_KERNEL);
372 channels[0] = &pwm_fan_channel_pwm;
374 if (tach_count > 0) {
377 ctx->irq = platform_get_irq(pdev, 0);
378 if (ctx->irq == -EPROBE_DEFER)
381 ret = devm_request_irq(dev, ctx->irq, pulse_handler, 0,
385 "Failed to request interrupt: %d\n",
391 of_property_read_u32(dev->of_node,
392 "pulses-per-revolution",
394 ctx->pulses_per_revolution = ppr;
395 if (!ctx->pulses_per_revolution) {
396 dev_err(dev, "pulses-per-revolution can't be zero.\n");
400 dev_dbg(dev, "tach: irq=%d, pulses_per_revolution=%d\n",
401 ctx->irq, ctx->pulses_per_revolution);
403 ctx->sample_start = ktime_get();
404 mod_timer(&ctx->rpm_timer, jiffies + HZ);
406 channels[1] = &pwm_fan_channel_fan;
409 ctx->info.ops = &pwm_fan_hwmon_ops;
410 ctx->info.info = channels;
412 hwmon = devm_hwmon_device_register_with_info(dev, "pwmfan",
413 ctx, &ctx->info, NULL);
415 dev_err(dev, "Failed to register hwmon device\n");
416 return PTR_ERR(hwmon);
419 ret = pwm_fan_of_get_cooling_data(dev, ctx);
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);
430 "Failed to register pwm-fan as cooling device: %d\n",
435 thermal_cdev_update(cdev);
441 static int pwm_fan_disable(struct device *dev)
443 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
444 struct pwm_args args;
447 pwm_get_args(ctx->pwm, &args);
449 if (ctx->pwm_value) {
450 ret = pwm_config(ctx->pwm, 0, args.period);
454 pwm_disable(ctx->pwm);
458 ret = regulator_disable(ctx->reg_en);
460 dev_err(dev, "Failed to disable fan supply: %d\n", ret);
468 static void pwm_fan_shutdown(struct platform_device *pdev)
470 pwm_fan_disable(&pdev->dev);
473 #ifdef CONFIG_PM_SLEEP
474 static int pwm_fan_suspend(struct device *dev)
476 return pwm_fan_disable(dev);
479 static int pwm_fan_resume(struct device *dev)
481 struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
482 struct pwm_args pargs;
487 ret = regulator_enable(ctx->reg_en);
489 dev_err(dev, "Failed to enable fan supply: %d\n", ret);
494 if (ctx->pwm_value == 0)
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);
502 return pwm_enable(ctx->pwm);
506 static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
508 static const struct of_device_id of_pwm_fan_match[] = {
509 { .compatible = "pwm-fan", },
512 MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
514 static struct platform_driver pwm_fan_driver = {
515 .probe = pwm_fan_probe,
516 .shutdown = pwm_fan_shutdown,
520 .of_match_table = of_pwm_fan_match,
524 module_platform_driver(pwm_fan_driver);
526 MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
527 MODULE_ALIAS("platform:pwm-fan");
528 MODULE_DESCRIPTION("PWM FAN driver");
529 MODULE_LICENSE("GPL");