leds: pca9532: Extend pca9532 device tree support

This patch extends the device tree support for the pca9532 by adding
the leds 'default-state' property.
Signed-off-by: Felix Brack <fb@ltec.ch>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

Documentation/devicetree/bindings/leds/leds-pca9532.txt

@@ -17,6 +17,8 @@ Optional sub-node properties:
 	- label: see Documentation/devicetree/bindings/leds/common.txt
 	- type: Output configuration, see dt-bindings/leds/leds-pca9532.h (default NONE)
 	- linux,default-trigger: see Documentation/devicetree/bindings/leds/common.txt
+	- default-state: see Documentation/devicetree/bindings/leds/common.txt
+	  This property is only valid for sub-nodes of type <PCA9532_TYPE_LED>.
 
 Example:
   #include <dt-bindings/leds/leds-pca9532.h>
@@ -33,6 +35,14 @@ Example:
       label = "pca:green:power";
       type = <PCA9532_TYPE_LED>;
     };
+    kernel-booting {
+      type = <PCA9532_TYPE_LED>;
+      default-state = "on";
+    };
+    sys-stat {
+      type = <PCA9532_TYPE_LED>;
+      default-state = "keep"; // don't touch, was set by U-Boot
+    };
   };
 
 For more product information please see the link below:

drivers/leds/leds-pca9532.c

@@ -254,6 +254,21 @@ static void pca9532_input_work(struct work_struct *work)
 	mutex_unlock(&data->update_lock);
 }
 
+static enum pca9532_state pca9532_getled(struct pca9532_led *led)
+{
+	struct i2c_client *client = led->client;
+	struct pca9532_data *data = i2c_get_clientdata(client);
+	u8 maxleds = data->chip_info->num_leds;
+	char reg;
+	enum pca9532_state ret;
+
+	mutex_lock(&data->update_lock);
+	reg = i2c_smbus_read_byte_data(client, LED_REG(maxleds, led->id));
+	ret = reg >> LED_NUM(led->id)/2;
+	mutex_unlock(&data->update_lock);
+	return ret;
+}
+
 #ifdef CONFIG_LEDS_PCA9532_GPIO
 static int pca9532_gpio_request_pin(struct gpio_chip *gc, unsigned offset)
 {
@@ -366,7 +381,10 @@ static int pca9532_configure(struct i2c_client *client,
 			gpios++;
 			break;
 		case PCA9532_TYPE_LED:
-			led->state = pled->state;
+			if (pled->state == PCA9532_KEEP)
+				led->state = pca9532_getled(led);
+			else
+				led->state = pled->state;
 			led->name = pled->name;
 			led->ldev.name = led->name;
 			led->ldev.default_trigger = pled->default_trigger;
@@ -456,6 +474,7 @@ pca9532_of_populate_pdata(struct device *dev, struct device_node *np)
 	const struct of_device_id *match;
 	int devid, maxleds;
 	int i = 0;
+	const char *state;
 
 	match = of_match_device(of_pca9532_leds_match, dev);
 	if (!match)
@@ -475,6 +494,12 @@ pca9532_of_populate_pdata(struct device *dev, struct device_node *np)
 		of_property_read_u32(child, "type", &pdata->leds[i].type);
 		of_property_read_string(child, "linux,default-trigger",
 					&pdata->leds[i].default_trigger);
+		if (!of_property_read_string(child, "default-state", &state)) {
+			if (!strcmp(state, "on"))
+				pdata->leds[i].state = PCA9532_ON;
+			else if (!strcmp(state, "keep"))
+				pdata->leds[i].state = PCA9532_KEEP;
+		}
 		if (++i >= maxleds) {
 			of_node_put(child);
 			break;

include/linux/leds-pca9532.h

@@ -22,7 +22,8 @@ enum pca9532_state {
 	PCA9532_OFF  = 0x0,
 	PCA9532_ON   = 0x1,
 	PCA9532_PWM0 = 0x2,
-	PCA9532_PWM1 = 0x3
+	PCA9532_PWM1 = 0x3,
+	PCA9532_KEEP = 0xff,
 };
 
 struct pca9532_led {
@@ -44,4 +45,3 @@ struct pca9532_platform_data {
 };
 
 #endif /* __LINUX_PCA9532_H */
-