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>

diff --git a/Documentation/devicetree/bindings/video/backlight/lp855x.txt b/Documentation/devicetree/bindings/video/backlight/lp855x.txt
new file mode 100644 (file)
index 0000000..1482103
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/backlight/lp855x.txt
@@ -0,0 +1,41 @@
+lp855x bindings
+
+Required properties:
+  - compatible: "ti,lp8550", "ti,lp8551", "ti,lp8552", "ti,lp8553",
+                "ti,lp8556", "ti,lp8557"
+  - reg: I2C slave address (u8)
+  - dev-ctrl: Value of DEVICE CONTROL register (u8). It depends on the device.
+
+Optional properties:
+  - bl-name: Backlight device name (string)
+  - init-brt: Initial value of backlight brightness (u8)
+  - pwm-period: PWM period value. Set only PWM input mode used (u32)
+  - rom-addr: Register address of ROM area to be updated (u8)
+  - rom-val: Register value to be updated (u8)
+
+Example:
+
+       /* LP8556 */
+       backlight@2c {
+               compatible = "ti,lp8556";
+               reg = <0x2c>;
+
+               bl-name = "lcd-bl";
+               dev-ctrl = /bits/ 8 <0x85>;
+               init-brt = /bits/ 8 <0x10>;
+       };
+
+       /* LP8557 */
+       backlight@2c {
+               compatible = "ti,lp8557";
+               reg = <0x2c>;
+
+               dev-ctrl = /bits/ 8 <0x41>;
+               init-brt = /bits/ 8 <0x0a>;
+
+               /* 4V OV, 4 output LED string enabled */
+               rom_14h {
+                       rom-addr = /bits/ 8 <0x14>;
+                       rom-val = /bits/ 8 <0xcf>;
+               };
+       };

diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
index f558f8f329e52c8f831232e948f6b85a3a5b4f12..a0e1e02bdc2e1f1b696bfef26ccdc8d794dd3e34 100644 (file)
--- 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,