linux-kernel - [PATCH 1/7] leds-lm3530: support pwm input mode

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Date:	Thu, 19 Jan 2012 17:46:13 -0800
From:	"Kim, Milo" <Milo.Kim@...com>
To:	"Linus Walleij" <linus.walleij@...aro.org>,
	"shreshthakumar.sahu@...ricsson.com" 
	<shreshthakumar.sahu@...ricsson.com>
cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"rpurdie@...ys.net" <rpurdie@...ys.net>
Subject: [PATCH 1/7] leds-lm3530: support pwm input mode

* add 'struct lm3530_pwm_data' in the platform data
  The pwm data is the platform specific functions which generate the pwm.
  The pwm data is only valid when brightness is pwm input mode.
  Functions should be implemented by the pwm driver.
  pwm_set_intensity() : set duty of pwm.
  pwm_get_intensity() : get current duty of pwm.

* brightness control by pwm
  If the control mode is pwm, then brightness is changed by the duty of pwm.
  So pwm platform function should be called in lm3530_brightness_set().

* do not update brightness register when pwm input mode
  In pwm input mode, brightness register is not used.
  If any value is updated in this register, then the led will be off.

* patched based on kernel 3.0.1

Signed-off-by: Milo(Woogyom) Kim <milo.kim@...com>

diff --git a/drivers/leds/leds-lm3530.c b/drivers/leds/leds-lm3530.c
index 4d7ce76..3135734 100644
--- a/drivers/leds/leds-lm3530.c
+++ b/drivers/leds/leds-lm3530.c
@@ -211,6 +211,11 @@ static int lm3530_init_registers(struct lm3530_data *drvdata)
 	}
 
 	for (i = 0; i < LM3530_REG_MAX; i++) {
+		/* do not update brightness register when pwm mode */
+		if (lm3530_reg[i] == LM3530_BRT_CTRL_REG &&
+		    drvdata->mode == LM3530_BL_MODE_PWM)
+			continue;
+
 		ret = i2c_smbus_write_byte_data(client,
 				lm3530_reg[i], reg_val[i]);
 		if (ret)
@@ -226,6 +231,9 @@ static void lm3530_brightness_set(struct led_classdev *led_cdev,
 	int err;
 	struct lm3530_data *drvdata =
 	    container_of(led_cdev, struct lm3530_data, led_dev);
+	struct lm3530_platform_data *pdata = drvdata->pdata;
+	struct lm3530_pwm_data *pwm = &pdata->pwm_data;
+	u8 max_brightness = led_cdev->max_brightness;
 
 	switch (drvdata->mode) {
 	case LM3530_BL_MODE_MANUAL:
@@ -259,6 +267,8 @@ static void lm3530_brightness_set(struct led_classdev *led_cdev,
 	case LM3530_BL_MODE_ALS:
 		break;
 	case LM3530_BL_MODE_PWM:
+		if (pwm->pwm_set_intensity)
+			pwm->pwm_set_intensity(brt_val, max_brightness);
 		break;
 	default:
 		break;
@@ -281,14 +291,7 @@ static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute
 		return -EINVAL;
 	}
 
-	if (mode == LM3530_BL_MODE_MANUAL)
-		drvdata->mode = LM3530_BL_MODE_MANUAL;
-	else if (mode == LM3530_BL_MODE_ALS)
-		drvdata->mode = LM3530_BL_MODE_ALS;
-	else if (mode == LM3530_BL_MODE_PWM) {
-		dev_err(dev, "PWM mode not supported\n");
-		return -EINVAL;
-	}
+	drvdata->mode = mode;
 
 	err = lm3530_init_registers(drvdata);
 	if (err) {
diff --git a/include/linux/led-lm3530.h b/include/linux/led-lm3530.h
index 58592fa..5534d1e 100644
--- a/include/linux/led-lm3530.h
+++ b/include/linux/led-lm3530.h
@@ -72,6 +72,12 @@ enum lm3530_als_mode {
 	LM3530_INPUT_CEIL,	/* Max of ALS1 and ALS2 */
 };
 
+/* PWM Platform Specific Data */
+struct lm3530_pwm_data {
+	void (*pwm_set_intensity) (int brightness, int max_brightness);
+	int (*pwm_get_intensity) (int max_brightness);
+};
+
 /**
  * struct lm3530_platform_data
  * @mode: mode of operation i.e. Manual, ALS or PWM
@@ -85,6 +91,7 @@ enum lm3530_als_mode {
  * @als1_resistor_sel: internal resistance from ALS1 input to ground
  * @als2_resistor_sel: internal resistance from ALS2 input to ground
  * @brt_val: brightness value (0-255)
+ * @pwm_data: PWM control functions. only valid when the mode is PWM.
  */
 struct lm3530_platform_data {
 	enum lm3530_mode mode;
@@ -102,6 +109,8 @@ struct lm3530_platform_data {
 	u8 als2_resistor_sel;
 
 	u8 brt_val;
+
+	struct lm3530_pwm_data pwm_data;
 };
 
 #endif	/* _LINUX_LED_LM3530_H__ */
-- 
1.7.4.1


Best Regards,
Milo (Woogyom) Kim
Texas Instruments Incorporated

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