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

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Message-id: <1418897591-18332-9-git-send-email-l.majewski@samsung.com>
Date:	Thu, 18 Dec 2014 11:13:10 +0100
From:	Lukasz Majewski <l.majewski@...sung.com>
To:	Eduardo Valentin <edubezval@...il.com>,
	Kamil Debski <k.debski@...sung.com>,
	Jean Delvare <jdelvare@...e.de>,
	Guenter Roeck <linux@...ck-us.net>
Cc:	lm-sensors@...sensors.org,
	Linux PM list <linux-pm@...r.kernel.org>,
	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>, devicetree@...r.kernel.org,
	Lukasz Majewski <l.majewski@...ess.pl>,
	Kukjin Kim <kgene.kim@...sung.com>,
	linux-kernel@...r.kernel.org,
	Sylwester Nawrocki <s.nawrocki@...sung.com>,
	Lukasz Majewski <l.majewski@...sung.com>
Subject: [PATCH 8/9] hwmon: thermal: Provide 'default-pulse-width' property to
 setup FAN on boot

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@...sung.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

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