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 <l.majewski@samsung.com> Acked-by: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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2e5219c771
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@ -24,6 +24,7 @@
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#include <linux/platform_device.h>
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#include <linux/pwm.h>
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#include <linux/sysfs.h>
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#include <linux/thermal.h>
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#define MAX_PWM 255
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@ -34,6 +35,7 @@ struct pwm_fan_ctx {
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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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};
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static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
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@ -68,6 +70,17 @@ exit_set_pwm_err:
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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 ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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@ -82,6 +95,7 @@ static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
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if (ret)
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return ret;
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pwm_fan_update_state(ctx, pwm);
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return count;
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}
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@ -103,6 +117,62 @@ static struct attribute *pwm_fan_attrs[] = {
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ATTRIBUTE_GROUPS(pwm_fan);
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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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int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx)
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{
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struct device_node *np = dev->of_node;
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@ -145,8 +215,9 @@ int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx)
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static int pwm_fan_probe(struct platform_device *pdev)
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{
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struct device *hwmon;
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struct thermal_cooling_device *cdev;
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struct pwm_fan_ctx *ctx;
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struct device *hwmon;
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int duty_cycle;
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int ret;
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@ -193,6 +264,21 @@ static int pwm_fan_probe(struct platform_device *pdev)
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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 = thermal_of_cooling_device_register(pdev->dev.of_node,
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"pwm-fan", ctx,
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&pwm_fan_cooling_ops);
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if (IS_ERR(cdev)) {
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dev_err(&pdev->dev,
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"Failed to register pwm-fan as cooling device");
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pwm_disable(ctx->pwm);
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return PTR_ERR(cdev);
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}
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ctx->cdev = cdev;
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thermal_cdev_update(cdev);
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}
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return 0;
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}
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@ -200,6 +286,7 @@ static int pwm_fan_remove(struct platform_device *pdev)
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{
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struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
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thermal_cooling_device_unregister(ctx->cdev);
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if (ctx->pwm_value)
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pwm_disable(ctx->pwm);
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return 0;
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