[PATCH 8/9] hwmon: thermal: Provide 'default-pulse-width' property to setup FAN on boot

Lukasz Majewski
2014-12-18T10:13:10Z

Up till now the PWM fan was enabled by default in the pwm-fan driver.
Now, by defining 'default-pulse-width' device tree property, it is possible
to configure the fan RPM on boot. By specifying value of 0, one can disable it.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
---
drivers/hwmon/pwm-fan.c | 34 ++++++++++++++++------------------
1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 97b77e9..c1cf48b 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -34,6 +34,7 @@ struct pwm_fan_ctx {
unsigned int pwm_value;
unsigned int pwm_fan_state;
unsigned int pwm_fan_max_state;
+ unsigned int pwm_fan_default_width;
unsigned int *pwm_fan_cooling_states;
};

@@ -172,8 +173,21 @@ static const struct thermal_cooling_device_ops pwm_fan_cooling_ops = {
int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx)
{
struct device_node *np = dev->of_node;
+ int len, num, i, ret;
struct property *pp;
- int len, num, i;
+
+ ret = of_property_read_u32(np, "default-pulse-width",
+ &ctx->pwm_fan_default_width);
+ if (ret) {
+ dev_err(dev, "Property: 'default-pulse-width' not found\n");
+ return -EINVAL;
+ }
+
+ if (ctx->pwm_fan_default_width > MAX_PWM) {
+ dev_err(dev, "'default-pulse-width %d larger than %d\n",
+ ctx->pwm_fan_default_width, MAX_PWM);
+ return -EINVAL;
+ }

pp = of_find_property(np, "cooling-pwm-values", &len);
if (!pp) {
@@ -217,7 +231,6 @@ static int pwm_fan_probe(struct platform_device *pdev)
struct thermal_cooling_device *cdev;
struct pwm_fan_ctx *ctx;
struct device *hwmon;
- int duty_cycle;
int ret;

ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
@@ -237,22 +250,7 @@ static int pwm_fan_probe(struct platform_device *pdev)
if (ret)
return ret;

- /* Set duty cycle to maximum allowed */
- duty_cycle = ctx->pwm->period - 1;
- ctx->pwm_value = MAX_PWM;
-
- ret = pwm_config(ctx->pwm, duty_cycle, ctx->pwm->period);
- if (ret) {
- dev_err(&pdev->dev, "Failed to configure PWM\n");
- return ret;
- }
-
- /* Enbale PWM output */
- ret = pwm_enable(ctx->pwm);
- if (ret) {
- dev_err(&pdev->dev, "Failed to enable PWM\n");
- return ret;
- }
+ __set_pwm(ctx, ctx->pwm_fan_default_width);

hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan",
ctx, pwm_fan_groups);
--
2.0.0.rc2