backlight: gpio-backlight: Add DT support

Signed-off-by: Denis Carikli <denis@eukrea.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

1 files changed, 51 insertions, 7 deletions

diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index 81fb12770c2a..a2eba12e1cb7 100644
--- a/drivers/video/backlight/gpio_backlight.c
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -13,6 +13,8 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/platform_data/gpio_backlight.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
@@ -23,6 +25,7 @@ struct gpio_backlight {
 
         int gpio;
         int active;
+        int def_value;
 };
 
 static int gpio_backlight_update_status(struct backlight_device *bl)
@@ -60,6 +63,29 @@ static const struct backlight_ops gpio_backlight_ops = {
         .check_fb       = gpio_backlight_check_fb,
 };
 
+static int gpio_backlight_probe_dt(struct platform_device *pdev,
+                                   struct gpio_backlight *gbl)
+{
+        struct device_node *np = pdev->dev.of_node;
+        enum of_gpio_flags gpio_flags;
+
+        gbl->gpio = of_get_gpio_flags(np, 0, &gpio_flags);
+
+        if (!gpio_is_valid(gbl->gpio)) {
+                if (gbl->gpio != -EPROBE_DEFER) {
+                        dev_err(&pdev->dev,
+                                "Error: The gpios parameter is missing or invalid.\n");
+                }
+                return gbl->gpio;
+        }
+
+        gbl->active = (gpio_flags & OF_GPIO_ACTIVE_LOW) ? 0 : 1;
+
+        gbl->def_value = of_property_read_bool(np, "default-on");
+
+        return 0;
+}
+
 static int gpio_backlight_probe(struct platform_device *pdev)
 {
         struct gpio_backlight_platform_data *pdata =
@@ -67,10 +93,12 @@ static int gpio_backlight_probe(struct platform_device *pdev)
         struct backlight_properties props;
         struct backlight_device *bl;
         struct gpio_backlight *gbl;
+        struct device_node *np = pdev->dev.of_node;
         int ret;
 
-        if (!pdata) {
-                dev_err(&pdev->dev, "failed to find platform data\n");
+        if (!pdata && !np) {
+                dev_err(&pdev->dev,
+                        "failed to find platform data or device tree node.\n");
                 return -ENODEV;
         }
 
@@ -79,14 +107,22 @@ static int gpio_backlight_probe(struct platform_device *pdev)
                 return -ENOMEM;
 
         gbl->dev = &pdev->dev;
-        gbl->fbdev = pdata->fbdev;
-        gbl->gpio = pdata->gpio;
-        gbl->active = pdata->active_low ? 0 : 1;
+
+        if (np) {
+                ret = gpio_backlight_probe_dt(pdev, gbl);
+                if (ret)
+                        return ret;
+        } else {
+                gbl->fbdev = pdata->fbdev;
+                gbl->gpio = pdata->gpio;
+                gbl->active = pdata->active_low ? 0 : 1;
+                gbl->def_value = pdata->def_value;
+        }
 
         ret = devm_gpio_request_one(gbl->dev, gbl->gpio, GPIOF_DIR_OUT |
                                     (gbl->active ? GPIOF_INIT_LOW
                                                  : GPIOF_INIT_HIGH),
-                                    pdata->name);
+                                    pdata ? pdata->name : "backlight");
         if (ret < 0) {
                 dev_err(&pdev->dev, "unable to request GPIO\n");
                 return ret;
@@ -103,17 +139,25 @@ static int gpio_backlight_probe(struct platform_device *pdev)
                 return PTR_ERR(bl);
         }
 
-        bl->props.brightness = pdata->def_value;
+        bl->props.brightness = gbl->def_value;
         backlight_update_status(bl);
 
         platform_set_drvdata(pdev, bl);
         return 0;
 }
 
+#ifdef CONFIG_OF
+static struct of_device_id gpio_backlight_of_match[] = {
+        { .compatible = "gpio-backlight" },
+        { /* sentinel */ }
+};
+#endif
+
 static struct platform_driver gpio_backlight_driver = {
         .driver         = {
                 .name           = "gpio-backlight",
                 .owner          = THIS_MODULE,
+                .of_match_table = of_match_ptr(gpio_backlight_of_match),
         },
         .probe          = gpio_backlight_probe,
 };