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545 lines
12 KiB
545 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* pwm-fan.c - Hwmon driver for fans connected to PWM lines. |
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* |
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* Copyright (c) 2014 Samsung Electronics Co., Ltd. |
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* |
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* Author: Kamil Debski <[email protected]> |
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*/ |
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#include <linux/hwmon.h> |
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#include <linux/interrupt.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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#include <linux/pwm.h> |
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#include <linux/regulator/consumer.h> |
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#include <linux/sysfs.h> |
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#include <linux/thermal.h> |
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#include <linux/timer.h> |
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#define MAX_PWM 255 |
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struct pwm_fan_tach { |
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int irq; |
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atomic_t pulses; |
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unsigned int rpm; |
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u8 pulses_per_revolution; |
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}; |
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struct pwm_fan_ctx { |
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struct mutex lock; |
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struct pwm_device *pwm; |
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struct pwm_state pwm_state; |
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struct regulator *reg_en; |
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int tach_count; |
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struct pwm_fan_tach *tachs; |
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ktime_t sample_start; |
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struct timer_list rpm_timer; |
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unsigned int pwm_value; |
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unsigned int pwm_fan_state; |
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unsigned int pwm_fan_max_state; |
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unsigned int *pwm_fan_cooling_levels; |
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struct thermal_cooling_device *cdev; |
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struct hwmon_chip_info info; |
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struct hwmon_channel_info fan_channel; |
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}; |
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static const u32 pwm_fan_channel_config_pwm[] = { |
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HWMON_PWM_INPUT, |
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0 |
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}; |
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static const struct hwmon_channel_info pwm_fan_channel_pwm = { |
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.type = hwmon_pwm, |
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.config = pwm_fan_channel_config_pwm, |
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}; |
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/* This handler assumes self resetting edge triggered interrupt. */ |
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static irqreturn_t pulse_handler(int irq, void *dev_id) |
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{ |
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struct pwm_fan_tach *tach = dev_id; |
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atomic_inc(&tach->pulses); |
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return IRQ_HANDLED; |
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} |
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static void sample_timer(struct timer_list *t) |
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{ |
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struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer); |
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unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start); |
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int i; |
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if (delta) { |
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for (i = 0; i < ctx->tach_count; i++) { |
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struct pwm_fan_tach *tach = &ctx->tachs[i]; |
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int pulses; |
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pulses = atomic_read(&tach->pulses); |
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atomic_sub(pulses, &tach->pulses); |
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tach->rpm = (unsigned int)(pulses * 1000 * 60) / |
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(tach->pulses_per_revolution * delta); |
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} |
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ctx->sample_start = ktime_get(); |
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} |
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mod_timer(&ctx->rpm_timer, jiffies + HZ); |
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} |
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static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) |
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{ |
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unsigned long period; |
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int ret = 0; |
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struct pwm_state *state = &ctx->pwm_state; |
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mutex_lock(&ctx->lock); |
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if (ctx->pwm_value == pwm) |
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goto exit_set_pwm_err; |
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period = state->period; |
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state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM); |
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state->enabled = pwm ? true : false; |
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ret = pwm_apply_state(ctx->pwm, state); |
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if (!ret) |
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ctx->pwm_value = pwm; |
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exit_set_pwm_err: |
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mutex_unlock(&ctx->lock); |
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return ret; |
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} |
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static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm) |
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{ |
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int i; |
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for (i = 0; i < ctx->pwm_fan_max_state; ++i) |
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if (pwm < ctx->pwm_fan_cooling_levels[i + 1]) |
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break; |
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ctx->pwm_fan_state = i; |
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} |
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static int pwm_fan_write(struct device *dev, enum hwmon_sensor_types type, |
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u32 attr, int channel, long val) |
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{ |
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struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); |
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int ret; |
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if (val < 0 || val > MAX_PWM) |
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return -EINVAL; |
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ret = __set_pwm(ctx, val); |
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if (ret) |
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return ret; |
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pwm_fan_update_state(ctx, val); |
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return 0; |
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} |
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static int pwm_fan_read(struct device *dev, enum hwmon_sensor_types type, |
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u32 attr, int channel, long *val) |
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{ |
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struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); |
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switch (type) { |
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case hwmon_pwm: |
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*val = ctx->pwm_value; |
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return 0; |
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case hwmon_fan: |
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*val = ctx->tachs[channel].rpm; |
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return 0; |
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default: |
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return -ENOTSUPP; |
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} |
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} |
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static umode_t pwm_fan_is_visible(const void *data, |
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enum hwmon_sensor_types type, |
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u32 attr, int channel) |
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{ |
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switch (type) { |
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case hwmon_pwm: |
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return 0644; |
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case hwmon_fan: |
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return 0444; |
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default: |
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return 0; |
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} |
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} |
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static const struct hwmon_ops pwm_fan_hwmon_ops = { |
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.is_visible = pwm_fan_is_visible, |
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.read = pwm_fan_read, |
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.write = pwm_fan_write, |
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}; |
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/* thermal cooling device callbacks */ |
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static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev, |
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unsigned long *state) |
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{ |
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struct pwm_fan_ctx *ctx = cdev->devdata; |
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if (!ctx) |
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return -EINVAL; |
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*state = ctx->pwm_fan_max_state; |
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return 0; |
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} |
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static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev, |
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unsigned long *state) |
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{ |
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struct pwm_fan_ctx *ctx = cdev->devdata; |
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if (!ctx) |
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return -EINVAL; |
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*state = ctx->pwm_fan_state; |
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return 0; |
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} |
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static int |
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pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) |
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{ |
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struct pwm_fan_ctx *ctx = cdev->devdata; |
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int ret; |
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if (!ctx || (state > ctx->pwm_fan_max_state)) |
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return -EINVAL; |
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if (state == ctx->pwm_fan_state) |
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return 0; |
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ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]); |
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if (ret) { |
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dev_err(&cdev->device, "Cannot set pwm!\n"); |
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return ret; |
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} |
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ctx->pwm_fan_state = state; |
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return ret; |
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} |
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static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = { |
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.get_max_state = pwm_fan_get_max_state, |
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.get_cur_state = pwm_fan_get_cur_state, |
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.set_cur_state = pwm_fan_set_cur_state, |
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}; |
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static int pwm_fan_of_get_cooling_data(struct device *dev, |
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struct pwm_fan_ctx *ctx) |
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{ |
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struct device_node *np = dev->of_node; |
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int num, i, ret; |
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if (!of_find_property(np, "cooling-levels", NULL)) |
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return 0; |
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ret = of_property_count_u32_elems(np, "cooling-levels"); |
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if (ret <= 0) { |
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dev_err(dev, "Wrong data!\n"); |
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return ret ? : -EINVAL; |
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} |
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num = ret; |
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ctx->pwm_fan_cooling_levels = devm_kcalloc(dev, num, sizeof(u32), |
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GFP_KERNEL); |
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if (!ctx->pwm_fan_cooling_levels) |
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return -ENOMEM; |
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ret = of_property_read_u32_array(np, "cooling-levels", |
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ctx->pwm_fan_cooling_levels, num); |
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if (ret) { |
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dev_err(dev, "Property 'cooling-levels' cannot be read!\n"); |
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return ret; |
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} |
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for (i = 0; i < num; i++) { |
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if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) { |
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dev_err(dev, "PWM fan state[%d]:%d > %d\n", i, |
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ctx->pwm_fan_cooling_levels[i], MAX_PWM); |
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return -EINVAL; |
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} |
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} |
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ctx->pwm_fan_max_state = num - 1; |
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return 0; |
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} |
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static void pwm_fan_regulator_disable(void *data) |
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{ |
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regulator_disable(data); |
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} |
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static void pwm_fan_pwm_disable(void *__ctx) |
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{ |
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struct pwm_fan_ctx *ctx = __ctx; |
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ctx->pwm_state.enabled = false; |
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pwm_apply_state(ctx->pwm, &ctx->pwm_state); |
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del_timer_sync(&ctx->rpm_timer); |
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} |
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static int pwm_fan_probe(struct platform_device *pdev) |
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{ |
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struct thermal_cooling_device *cdev; |
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struct device *dev = &pdev->dev; |
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struct pwm_fan_ctx *ctx; |
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struct device *hwmon; |
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int ret; |
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const struct hwmon_channel_info **channels; |
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u32 *fan_channel_config; |
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int channel_count = 1; /* We always have a PWM channel. */ |
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int i; |
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ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL); |
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if (!ctx) |
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return -ENOMEM; |
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mutex_init(&ctx->lock); |
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ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL); |
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if (IS_ERR(ctx->pwm)) |
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return dev_err_probe(dev, PTR_ERR(ctx->pwm), "Could not get PWM\n"); |
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platform_set_drvdata(pdev, ctx); |
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ctx->reg_en = devm_regulator_get_optional(dev, "fan"); |
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if (IS_ERR(ctx->reg_en)) { |
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if (PTR_ERR(ctx->reg_en) != -ENODEV) |
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return PTR_ERR(ctx->reg_en); |
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ctx->reg_en = NULL; |
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} else { |
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ret = regulator_enable(ctx->reg_en); |
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if (ret) { |
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dev_err(dev, "Failed to enable fan supply: %d\n", ret); |
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return ret; |
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} |
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ret = devm_add_action_or_reset(dev, pwm_fan_regulator_disable, |
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ctx->reg_en); |
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if (ret) |
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return ret; |
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} |
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pwm_init_state(ctx->pwm, &ctx->pwm_state); |
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/* |
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* __set_pwm assumes that MAX_PWM * (period - 1) fits into an unsigned |
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* long. Check this here to prevent the fan running at a too low |
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* frequency. |
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*/ |
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if (ctx->pwm_state.period > ULONG_MAX / MAX_PWM + 1) { |
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dev_err(dev, "Configured period too big\n"); |
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return -EINVAL; |
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} |
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/* Set duty cycle to maximum allowed and enable PWM output */ |
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ret = __set_pwm(ctx, MAX_PWM); |
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if (ret) { |
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dev_err(dev, "Failed to configure PWM: %d\n", ret); |
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return ret; |
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} |
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timer_setup(&ctx->rpm_timer, sample_timer, 0); |
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ret = devm_add_action_or_reset(dev, pwm_fan_pwm_disable, ctx); |
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if (ret) |
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return ret; |
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ctx->tach_count = platform_irq_count(pdev); |
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if (ctx->tach_count < 0) |
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return dev_err_probe(dev, ctx->tach_count, |
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"Could not get number of fan tachometer inputs\n"); |
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dev_dbg(dev, "%d fan tachometer inputs\n", ctx->tach_count); |
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if (ctx->tach_count) { |
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channel_count++; /* We also have a FAN channel. */ |
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ctx->tachs = devm_kcalloc(dev, ctx->tach_count, |
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sizeof(struct pwm_fan_tach), |
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GFP_KERNEL); |
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if (!ctx->tachs) |
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return -ENOMEM; |
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ctx->fan_channel.type = hwmon_fan; |
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fan_channel_config = devm_kcalloc(dev, ctx->tach_count + 1, |
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sizeof(u32), GFP_KERNEL); |
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if (!fan_channel_config) |
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return -ENOMEM; |
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ctx->fan_channel.config = fan_channel_config; |
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} |
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channels = devm_kcalloc(dev, channel_count + 1, |
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sizeof(struct hwmon_channel_info *), GFP_KERNEL); |
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if (!channels) |
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return -ENOMEM; |
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channels[0] = &pwm_fan_channel_pwm; |
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for (i = 0; i < ctx->tach_count; i++) { |
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struct pwm_fan_tach *tach = &ctx->tachs[i]; |
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u32 ppr = 2; |
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tach->irq = platform_get_irq(pdev, i); |
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if (tach->irq == -EPROBE_DEFER) |
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return tach->irq; |
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if (tach->irq > 0) { |
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ret = devm_request_irq(dev, tach->irq, pulse_handler, 0, |
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pdev->name, tach); |
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if (ret) { |
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dev_err(dev, |
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"Failed to request interrupt: %d\n", |
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ret); |
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return ret; |
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} |
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} |
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of_property_read_u32_index(dev->of_node, |
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"pulses-per-revolution", |
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i, |
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&ppr); |
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tach->pulses_per_revolution = ppr; |
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if (!tach->pulses_per_revolution) { |
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dev_err(dev, "pulses-per-revolution can't be zero.\n"); |
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return -EINVAL; |
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} |
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fan_channel_config[i] = HWMON_F_INPUT; |
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dev_dbg(dev, "tach%d: irq=%d, pulses_per_revolution=%d\n", |
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i, tach->irq, tach->pulses_per_revolution); |
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} |
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if (ctx->tach_count > 0) { |
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ctx->sample_start = ktime_get(); |
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mod_timer(&ctx->rpm_timer, jiffies + HZ); |
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channels[1] = &ctx->fan_channel; |
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} |
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ctx->info.ops = &pwm_fan_hwmon_ops; |
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ctx->info.info = channels; |
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hwmon = devm_hwmon_device_register_with_info(dev, "pwmfan", |
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ctx, &ctx->info, NULL); |
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if (IS_ERR(hwmon)) { |
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dev_err(dev, "Failed to register hwmon device\n"); |
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return PTR_ERR(hwmon); |
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} |
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ret = pwm_fan_of_get_cooling_data(dev, ctx); |
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if (ret) |
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return ret; |
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ctx->pwm_fan_state = ctx->pwm_fan_max_state; |
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if (IS_ENABLED(CONFIG_THERMAL)) { |
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cdev = devm_thermal_of_cooling_device_register(dev, |
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dev->of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops); |
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if (IS_ERR(cdev)) { |
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ret = PTR_ERR(cdev); |
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dev_err(dev, |
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"Failed to register pwm-fan as cooling device: %d\n", |
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ret); |
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return ret; |
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} |
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ctx->cdev = cdev; |
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} |
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return 0; |
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} |
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static int pwm_fan_disable(struct device *dev) |
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{ |
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struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); |
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int ret; |
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if (ctx->pwm_value) { |
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/* keep ctx->pwm_state unmodified for pwm_fan_resume() */ |
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struct pwm_state state = ctx->pwm_state; |
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state.duty_cycle = 0; |
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state.enabled = false; |
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ret = pwm_apply_state(ctx->pwm, &state); |
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if (ret < 0) |
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return ret; |
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} |
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if (ctx->reg_en) { |
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ret = regulator_disable(ctx->reg_en); |
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if (ret) { |
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dev_err(dev, "Failed to disable fan supply: %d\n", ret); |
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return ret; |
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} |
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} |
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return 0; |
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} |
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static void pwm_fan_shutdown(struct platform_device *pdev) |
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{ |
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pwm_fan_disable(&pdev->dev); |
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} |
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#ifdef CONFIG_PM_SLEEP |
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static int pwm_fan_suspend(struct device *dev) |
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{ |
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return pwm_fan_disable(dev); |
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} |
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static int pwm_fan_resume(struct device *dev) |
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{ |
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struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); |
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int ret; |
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if (ctx->reg_en) { |
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ret = regulator_enable(ctx->reg_en); |
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if (ret) { |
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dev_err(dev, "Failed to enable fan supply: %d\n", ret); |
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return ret; |
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} |
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} |
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if (ctx->pwm_value == 0) |
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return 0; |
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return pwm_apply_state(ctx->pwm, &ctx->pwm_state); |
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} |
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#endif |
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static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume); |
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static const struct of_device_id of_pwm_fan_match[] = { |
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{ .compatible = "pwm-fan", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, of_pwm_fan_match); |
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static struct platform_driver pwm_fan_driver = { |
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.probe = pwm_fan_probe, |
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.shutdown = pwm_fan_shutdown, |
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.driver = { |
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.name = "pwm-fan", |
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.pm = &pwm_fan_pm, |
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.of_match_table = of_pwm_fan_match, |
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}, |
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}; |
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module_platform_driver(pwm_fan_driver); |
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MODULE_AUTHOR("Kamil Debski <[email protected]>"); |
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MODULE_ALIAS("platform:pwm-fan"); |
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MODULE_DESCRIPTION("PWM FAN driver"); |
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MODULE_LICENSE("GPL");
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