[PATCH 6/9] hwmon: thermal: Read PWM FAN configuration from device tree

Lukasz Majewski
2014-12-18T10:14:47Z

Code for reading PWM FAN configuration data via device tree has been added.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
---
drivers/hwmon/pwm-fan.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 870e100..5854bb3 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -30,7 +30,10 @@
struct pwm_fan_ctx {
struct mutex lock;
struct pwm_device *pwm;
- unsigned char pwm_value;
+ unsigned int pwm_value;
+ unsigned int pwm_fan_state;
+ unsigned int pwm_fan_max_state;
+ unsigned int *pwm_fan_cooling_states;
};

static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
@@ -100,6 +103,49 @@ static struct attribute *pwm_fan_attrs[] = {

ATTRIBUTE_GROUPS(pwm_fan);

+int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx)
+{
+ struct device_node *np = dev->of_node;
+ struct property *pp;
+ int len, num, i;
+
+ pp = of_find_property(np, "cooling-pwm-values", &len);
+ if (!pp) {
+ dev_err(dev, "Property: 'cooling-pwm-values' not found\n");
+ return -EINVAL;
+ }
+
+ if (len == 0) {
+ dev_err(dev, "Length wrong value!\n");
+ return -EINVAL;
+ }
+
+ ctx->pwm_fan_cooling_states = devm_kzalloc(dev, len, GFP_KERNEL);
+ if (!ctx->pwm_fan_cooling_states) {
+ dev_err(dev, "Allocation failed for pwm dan cooling states\n");
+ return -ENOMEM;
+ }
+
+ num = len / sizeof(u32);
+ if (of_property_read_u32_array(np, pp->name,
+ ctx->pwm_fan_cooling_states, num)) {
+ dev_err(dev, "Property: %s cannot be read!\n", pp->name);
+ return -EINVAL;
+ }
+
+ for (i = 0; i < num; i++) {
+ if (ctx->pwm_fan_cooling_states[i] > MAX_PWM) {
+ dev_err(dev, "PWM fan state[%d]:%d > %d\n", i,
+ ctx->pwm_fan_cooling_states[i], MAX_PWM);
+ return -EINVAL;
+ }
+ }
+
+ ctx->pwm_fan_max_state = num - 1;
+
+ return 0;
+}
+
static int pwm_fan_probe(struct platform_device *pdev)
{
struct device *hwmon;
@@ -120,6 +166,9 @@ static int pwm_fan_probe(struct platform_device *pdev)
}

platform_set_drvdata(pdev, ctx);
+ ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx);
+ if (ret)
+ return ret;

/* Set duty cycle to maximum allowed */
duty_cycle = ctx->pwm->period - 1;
--
2.0.0.rc2