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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>
hifive-unleashed-5.1
Lukasz Majewski 2015-02-26 14:59:37 +01:00 committed by Guenter Roeck
parent 2e5219c771
commit b6bddec019
1 changed files with 88 additions and 1 deletions
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89
drivers/hwmon/pwm-fan.c
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@ -24,6 +24,7 @@
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/sysfs.h>
#include <linux/thermal.h>
#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;