546 lines
12 KiB
C
546 lines
12 KiB
C
// 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 <k.debski@samsung.com>
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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,
|
|
.of_match_table = of_pwm_fan_match,
|
|
},
|
|
};
|
|
|
|
module_platform_driver(pwm_fan_driver);
|
|
|
|
MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
|
|
MODULE_ALIAS("platform:pwm-fan");
|
|
MODULE_DESCRIPTION("PWM FAN driver");
|
|
MODULE_LICENSE("GPL");
|