leds: lp55xx: add support for Device Tree bindings

This patch allows the lp5521 driver to be successfully probed and
initialised when Device Tree support is enabled.

Based on a patch by Gabriel Fernandez, rewritten in accordance
with review feedback.

Cc: Gabriel Fernandez <gabriel.fernandez@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Milo Kim <milo.kim@ti.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

Documentation/devicetree/bindings/leds/leds-lp55xx.txt

@@ -0,0 +1,21 @@
+Binding for National Semiconductor LP55xx Led Drivers
+
+Required properties:
+- compatible: "national,lp5521" or "national,lp5523"
+- label: Used for naming LEDs
+- num-channel: Number of LED channels
+- led-cur: Current setting at each led channel (mA x10, 0 if led is not connected)
+- max-cur: Maximun current at each led channel.
+- clock-mode: Input clock mode, (0: automode, 1: internal, 2: external)
+
+example:
+
+lp5521@32 {
+	compatible = "national,lp5521";
+	reg = <0x32>;
+	label = "lp5521_pri";
+	num-channel = /bits/ 8 <3>;
+	led-cur = /bits/ 8 <0x2f 0x2f 0x2f>;
+	max-cur = /bits/ 8 <0x5f 0x5f 0x5f>;
+	clock-mode = /bits/8 <2>;
+};

drivers/leds/leds-lp5521.c

@@ -31,6 +31,7 @@
 #include <linux/mutex.h>
 #include <linux/platform_data/leds-lp55xx.h>
 #include <linux/slab.h>
+#include <linux/of.h>
 
 #include "leds-lp55xx-common.h"
 
@@ -416,12 +417,20 @@ static int lp5521_probe(struct i2c_client *client,
 	int ret;
 	struct lp55xx_chip *chip;
 	struct lp55xx_led *led;
-	struct lp55xx_platform_data *pdata = client->dev.platform_data;
-
-	if (!pdata) {
-		dev_err(&client->dev, "no platform data\n");
-		return -EINVAL;
+	struct lp55xx_platform_data *pdata;
+	struct device_node *np = client->dev.of_node;
+
+	if (!client->dev.platform_data) {
+		if (np) {
+			ret = lp55xx_of_populate_pdata(&client->dev, np);
+			if (ret < 0)
+				return ret;
+		} else {
+			dev_err(&client->dev, "no platform data\n");
+			return -EINVAL;
+		}
 	}
+	pdata = client->dev.platform_data;
 
 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
 	if (!chip)
@@ -481,6 +490,7 @@ static int lp5521_remove(struct i2c_client *client)
 
 static const struct i2c_device_id lp5521_id[] = {
 	{ "lp5521", 0 }, /* Three channel chip */
+	{ "national,lp5521", 0 }, /* OF compatible */
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, lp5521_id);

drivers/leds/leds-lp5523.c

@@ -429,12 +429,20 @@ static int lp5523_probe(struct i2c_client *client,
 	int ret;
 	struct lp55xx_chip *chip;
 	struct lp55xx_led *led;
-	struct lp55xx_platform_data *pdata = client->dev.platform_data;
-
-	if (!pdata) {
-		dev_err(&client->dev, "no platform data\n");
-		return -EINVAL;
+	struct lp55xx_platform_data *pdata;
+	struct device_node *np = client->dev.of_node;
+
+	if (!client->dev.platform_data) {
+		if (np) {
+			ret = lp55xx_of_populate_pdata(&client->dev, np);
+			if (ret < 0)
+				return ret;
+		} else {
+			dev_err(&client->dev, "no platform data\n");
+			return -EINVAL;
+		}
 	}
+	pdata = client->dev.platform_data;
 
 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
 	if (!chip)
@@ -495,6 +503,7 @@ static int lp5523_remove(struct i2c_client *client)
 static const struct i2c_device_id lp5523_id[] = {
 	{ "lp5523",  LP5523 },
 	{ "lp55231", LP55231 },
+	{ "national,lp5523", 0 }, /* OF compatible */
 	{ }
 };
 

drivers/leds/leds-lp55xx-common.c

@@ -19,6 +19,7 @@
 #include <linux/leds.h>
 #include <linux/module.h>
 #include <linux/platform_data/leds-lp55xx.h>
+#include <linux/slab.h>
 
 #include "leds-lp55xx-common.h"
 
@@ -554,6 +555,59 @@ void lp55xx_unregister_sysfs(struct lp55xx_chip *chip)
 }
 EXPORT_SYMBOL_GPL(lp55xx_unregister_sysfs);
 
+int lp55xx_of_populate_pdata(struct device *dev, struct device_node *np)
+{
+	struct lp55xx_platform_data *pdata;
+	u8 led_cur[3];
+	u8 max_cur[3];
+	u8 clock_mode;
+	u8 num_channel;
+	const char *label;
+	struct lp55xx_led_config *led_config;
+	int ret;
+	int i;
+
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	ret = of_property_read_u8(np, "num-channel", &num_channel);
+	if (ret < 0)
+		return ret;
+	ret = of_property_read_u8_array(np, "led-cur", led_cur, num_channel);
+	if (ret < 0)
+		return ret;
+	ret = of_property_read_u8_array(np, "max-cur", max_cur, num_channel);
+	if (ret < 0)
+		return ret;
+	ret = of_property_read_string(np, "label", &label);
+	if (ret < 0)
+		return ret;
+	ret = of_property_read_u8_array(np, "clock-mode", &clock_mode, 1);
+	if (ret < 0)
+		return ret;
+
+	led_config = devm_kzalloc(dev, sizeof(*led_config) * num_channel,
+				  GFP_KERNEL);
+	if (!led_config)
+		return -ENOMEM;
+
+	for (i = 0; i < num_channel; i++) {
+		led_config[i].chan_nr = i;
+		led_config[i].led_current = led_cur[i];
+		led_config[i].max_current = max_cur[i];
+	}
+	pdata->label = kzalloc(sizeof(char) * 32, GFP_KERNEL);
+	strcpy((char *)pdata->label, (char *) label);
+	pdata->led_config = &led_config[0];
+	pdata->num_channels = num_channel;
+	pdata->clock_mode = clock_mode;
+	dev->platform_data = pdata;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(lp55xx_of_populate_pdata);
+
 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
 MODULE_DESCRIPTION("LP55xx Common Driver");
 MODULE_LICENSE("GPL");

drivers/leds/leds-lp55xx-common.h

@@ -135,4 +135,8 @@ extern void lp55xx_unregister_leds(struct lp55xx_led *led,
 extern int lp55xx_register_sysfs(struct lp55xx_chip *chip);
 extern void lp55xx_unregister_sysfs(struct lp55xx_chip *chip);
 
+/* common device tree population function */
+extern int lp55xx_of_populate_pdata(struct device *dev,
+				    struct device_node *np);
+
 #endif /* _LEDS_LP55XX_COMMON_H */