DSI : Add the brigtness node for setting

Change-Id: Ifc5215e0b7f49b6d6e88225571e56a1d8eb6d600
Reviewed-on: https://tp-biosrd-v02/gerrit/82990
Reviewed-by: Jamess Huang(黃以民) <Jamess_Huang@asus.com>
Tested-by: Jamess Huang(黃以民) <Jamess_Huang@asus.com>

Author: ashinlin

drivers/misc/tinker_mcu.c

@@ -24,8 +24,10 @@
 #include <linux/workqueue.h>
 #include "tinker_mcu.h"
 
+#define BL_DEBUG 0
 static struct tinker_mcu_data *g_mcu_data;
 static int connected = 0;
+static int lcd_bright_level = 0;
 
 static int is_hex(char num)
 {
@@ -147,7 +149,7 @@ int tinker_mcu_set_bright(int bright)
 	if (bright > 0xff || bright < 0)
 		return -EINVAL;
 
-	LOG_INFO("bright = 0x%x\n", bright);
+	if(BL_DEBUG) LOG_INFO("set bright = 0x%x\n", bright);
 
 	cmd[0] = 0x86;
 	cmd[1] = bright;
@@ -158,10 +160,34 @@ int tinker_mcu_set_bright(int bright)
 		return ret != 0 ? ret : -ECOMM;
 	}
 
+	lcd_bright_level = bright;
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(tinker_mcu_set_bright);
 
+static ssize_t tinker_mcu_bl_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+    if(BL_DEBUG) LOG_INFO("get bright = 0x%x\n", lcd_bright_level);
+
+    return sprintf(buf, "%d\n", lcd_bright_level);
+}
+
+static ssize_t tinker_mcu_bl_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
+{
+	int value;
+
+	value = simple_strtoul(buf, NULL, 0);
+
+	if((value < 0) || (value > 255)) {
+		LOG_ERR("Invalid value for backlight setting, value = %d\n", value);
+	} else
+		tinker_mcu_set_bright(value);
+
+	return strnlen(buf, count);
+}
+static DEVICE_ATTR(tinker_mcu_bl, S_IRUGO | S_IWUSR, tinker_mcu_bl_show, tinker_mcu_bl_store);
+
 int tinker_mcu_is_connected(void)
 {
 	return connected;
@@ -198,6 +224,12 @@ static int tinker_mcu_probe(struct i2c_client *client,
 	}
 	connected = 1;
 
+	ret = device_create_file(&client->dev, &dev_attr_tinker_mcu_bl);
+	if (ret != 0) {
+		dev_err(&client->dev, "Failed to create tinker_mcu_bl sysfs files %d\n", ret);
+		return ret;
+	}
+
 	return 0;
 
 error: