From b6bddec01932b94a20b6a7bbb7ed9d98e82ec162 Mon Sep 17 00:00:00 2001 From: Lukasz Majewski Date: Thu, 26 Feb 2015 14:59:37 +0100 Subject: hwmon: (pwm-fan) Add support for using PWM FAN as a cooling device The PWM FAN device can now be used as a thermal cooling device. Signed-off-by: Lukasz Majewski Acked-by: Eduardo Valentin Signed-off-by: Guenter Roeck --- drivers/hwmon/pwm-fan.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 88 insertions(+), 1 deletion(-) (limited to 'drivers/hwmon/pwm-fan.c') diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c index e6ed3532deac..7c83dc4c8dbd 100644 --- a/drivers/hwmon/pwm-fan.c +++ b/drivers/hwmon/pwm-fan.c @@ -24,6 +24,7 @@ #include #include #include +#include #define MAX_PWM 255 @@ -34,6 +35,7 @@ struct pwm_fan_ctx { unsigned int pwm_fan_state; unsigned int pwm_fan_max_state; unsigned int *pwm_fan_cooling_levels; + struct thermal_cooling_device *cdev; }; static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) @@ -68,6 +70,17 @@ exit_set_pwm_err: return ret; } +static void pwm_fan_update_state(struct pwm_fan_ctx *ctx, unsigned long pwm) +{ + int i; + + for (i = 0; i < ctx->pwm_fan_max_state; ++i) + if (pwm < ctx->pwm_fan_cooling_levels[i + 1]) + break; + + ctx->pwm_fan_state = i; +} + static ssize_t set_pwm(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { @@ -82,6 +95,7 @@ static ssize_t set_pwm(struct device *dev, struct device_attribute *attr, if (ret) return ret; + pwm_fan_update_state(ctx, pwm); return count; } @@ -103,6 +117,62 @@ static struct attribute *pwm_fan_attrs[] = { ATTRIBUTE_GROUPS(pwm_fan); +/* thermal cooling device callbacks */ +static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev, + unsigned long *state) +{ + struct pwm_fan_ctx *ctx = cdev->devdata; + + if (!ctx) + return -EINVAL; + + *state = ctx->pwm_fan_max_state; + + return 0; +} + +static int pwm_fan_get_cur_state(struct thermal_cooling_device *cdev, + unsigned long *state) +{ + struct pwm_fan_ctx *ctx = cdev->devdata; + + if (!ctx) + return -EINVAL; + + *state = ctx->pwm_fan_state; + + return 0; +} + +static int +pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) +{ + struct pwm_fan_ctx *ctx = cdev->devdata; + int ret; + + if (!ctx || (state > ctx->pwm_fan_max_state)) + return -EINVAL; + + if (state == ctx->pwm_fan_state) + return 0; + + ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]); + if (ret) { + dev_err(&cdev->device, "Cannot set pwm!\n"); + return ret; + } + + ctx->pwm_fan_state = state; + + return ret; +} + +static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = { + .get_max_state = pwm_fan_get_max_state, + .get_cur_state = pwm_fan_get_cur_state, + .set_cur_state = pwm_fan_set_cur_state, +}; + int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx) { struct device_node *np = dev->of_node; @@ -145,8 +215,9 @@ int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx) static int pwm_fan_probe(struct platform_device *pdev) { - struct device *hwmon; + struct thermal_cooling_device *cdev; struct pwm_fan_ctx *ctx; + struct device *hwmon; int duty_cycle; int ret; @@ -193,6 +264,21 @@ static int pwm_fan_probe(struct platform_device *pdev) if (ret) return ret; + ctx->pwm_fan_state = ctx->pwm_fan_max_state; + if (IS_ENABLED(CONFIG_THERMAL)) { + cdev = thermal_of_cooling_device_register(pdev->dev.of_node, + "pwm-fan", ctx, + &pwm_fan_cooling_ops); + if (IS_ERR(cdev)) { + dev_err(&pdev->dev, + "Failed to register pwm-fan as cooling device"); + pwm_disable(ctx->pwm); + return PTR_ERR(cdev); + } + ctx->cdev = cdev; + thermal_cdev_update(cdev); + } + return 0; } @@ -200,6 +286,7 @@ static int pwm_fan_remove(struct platform_device *pdev) { struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); + thermal_cooling_device_unregister(ctx->cdev); if (ctx->pwm_value) pwm_disable(ctx->pwm); return 0; -- cgit