backlight: lp855x: add a device tree structure

Enable supporting the DT structure of LP855x family devices.  If the
platform data is NULL, the driver tries to parse a DT structure.  Then,
the platform data is copied from the DT.  Documentation is added as well.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 71 insertions, 2 deletions

diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
index f558f8f329e5..a0e1e02bdc2e 100644
--- a/drivers/video/backlight/lp855x_bl.c
+++ b/drivers/video/backlight/lp855x_bl.c
@@ -14,6 +14,7 @@
 #include <linux/i2c.h>
 #include <linux/backlight.h>
 #include <linux/err.h>
+#include <linux/of.h>
 #include <linux/platform_data/lp855x.h>
 #include <linux/pwm.h>
 
@@ -338,15 +339,71 @@ static const struct attribute_group lp855x_attr_group = {
         .attrs = lp855x_attributes,
 };
 
+#ifdef CONFIG_OF
+static int lp855x_parse_dt(struct device *dev, struct device_node *node)
+{
+        struct lp855x_platform_data *pdata;
+        int rom_length;
+
+        if (!node) {
+                dev_err(dev, "no platform data\n");
+                return -EINVAL;
+        }
+
+        pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+        if (!pdata)
+                return -ENOMEM;
+
+        of_property_read_string(node, "bl-name", &pdata->name);
+        of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
+        of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
+        of_property_read_u32(node, "pwm-period", &pdata->period_ns);
+
+        /* Fill ROM platform data if defined */
+        rom_length = of_get_child_count(node);
+        if (rom_length > 0) {
+                struct lp855x_rom_data *rom;
+                struct device_node *child;
+                int i = 0;
+
+                rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL);
+                if (!rom)
+                        return -ENOMEM;
+
+                for_each_child_of_node(node, child) {
+                        of_property_read_u8(child, "rom-addr", &rom[i].addr);
+                        of_property_read_u8(child, "rom-val", &rom[i].val);
+                        i++;
+                }
+
+                pdata->size_program = rom_length;
+                pdata->rom_data = &rom[0];
+        }
+
+        dev->platform_data = pdata;
+
+        return 0;
+}
+#else
+static int lp855x_parse_dt(struct device *dev, struct device_node *node)
+{
+        return -EINVAL;
+}
+#endif
+
 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 {
         struct lp855x *lp;
         struct lp855x_platform_data *pdata = cl->dev.platform_data;
+        struct device_node *node = cl->dev.of_node;
         int ret;
 
         if (!pdata) {
-                dev_err(&cl->dev, "no platform data supplied\n");
-                return -EINVAL;
+                ret = lp855x_parse_dt(&cl->dev, node);
+                if (ret < 0)
+                        return ret;
+
+                pdata = cl->dev.platform_data;
         }
 
         if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
@@ -408,6 +465,17 @@ static int lp855x_remove(struct i2c_client *cl)
         return 0;
 }
 
+static const struct of_device_id lp855x_dt_ids[] = {
+        { .compatible = "ti,lp8550", },
+        { .compatible = "ti,lp8551", },
+        { .compatible = "ti,lp8552", },
+        { .compatible = "ti,lp8553", },
+        { .compatible = "ti,lp8556", },
+        { .compatible = "ti,lp8557", },
+        { }
+};
+MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
+
 static const struct i2c_device_id lp855x_ids[] = {
         {"lp8550", LP8550},
         {"lp8551", LP8551},
@@ -422,6 +490,7 @@ MODULE_DEVICE_TABLE(i2c, lp855x_ids);
 static struct i2c_driver lp855x_driver = {
         .driver = {
                    .name = "lp855x",
+                   .of_match_table = of_match_ptr(lp855x_dt_ids),
                    },
         .probe = lp855x_probe,
         .remove = lp855x_remove,