DSI : Fix the kernel panic when system enter suspend mode with DSI panel

NOTE: Fine tune the commit "Add the backlight control node in /sys/class/backlight/rpi_backlight/brightness"

Change-Id: I2a4e4814183048539be2f1c03046b53e845e5573
Reviewed-on: https://tp-biosrd-v02/gerrit/83831
Reviewed-by: Jamess Huang(黃以民) <[email protected]>
Tested-by: Jamess Huang(黃以民) <[email protected]>
(cherry picked from commit f4ccd11)
Reviewed-on: https://tp-biosrd-v02/gerrit/83856

Author: shin_lin

drivers/misc/tinker_mcu.c

@@ -29,7 +29,6 @@
 static struct tinker_mcu_data *g_mcu_data;
 static int connected = 0;
 static int lcd_bright_level = 0;
-static struct device *rpi_backlight_device;
 
 static int is_hex(char num)
 {
@@ -168,6 +167,22 @@ int tinker_mcu_set_bright(int bright)
 }
 EXPORT_SYMBOL_GPL(tinker_mcu_set_bright);
 
+int tinker_mcu_get_brightness(void)
+{
+	return lcd_bright_level;
+}
+EXPORT_SYMBOL_GPL(tinker_mcu_get_brightness);
+
+static int tinker_mcu_bl_get_brightness(struct backlight_device *bd)
+{
+	return lcd_bright_level;
+}
+
+static const struct backlight_ops tinker_mcu_bl_ops = {
+	.get_brightness	= tinker_mcu_bl_get_brightness,
+};
+
+
 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);
@@ -189,7 +204,6 @@ static ssize_t tinker_mcu_bl_store(struct device *dev, struct device_attribute *
 	return strnlen(buf, count);
 }
 static DEVICE_ATTR(tinker_mcu_bl, S_IRUGO | S_IWUSR, tinker_mcu_bl_show, tinker_mcu_bl_store);
-static DEVICE_ATTR(brightness, S_IRUGO | S_IWUSR, tinker_mcu_bl_show, tinker_mcu_bl_store);
 
 int tinker_mcu_is_connected(void)
 {
@@ -202,6 +216,8 @@ static int tinker_mcu_probe(struct i2c_client *client,
 {
 	struct tinker_mcu_data *mcu_data;
 	int ret;
+	struct backlight_properties props;
+	struct backlight_device *bl;
 
 	LOG_INFO("address = 0x%x\n", client->addr);
 
@@ -227,28 +243,22 @@ static int tinker_mcu_probe(struct i2c_client *client,
 	}
 	connected = 1;
 
+	memset(&props, 0, sizeof(props));
+	props.type = BACKLIGHT_RAW;
+	props.max_brightness = 255;
+
+	bl = backlight_device_register("rpi_backlight", NULL, NULL,
+					   &tinker_mcu_bl_ops, &props);
+	if (IS_ERR(bl)) {
+		pr_err("unable to register backlight device\n");
+	}
+
 	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;
 	}
 
-	rpi_backlight_device = device_create(backlight_class, NULL, MKDEV(0, 0), NULL,
-				     "rpi_backlight");
-	if (IS_ERR(rpi_backlight_device)) {
-		printk(KERN_WARNING "Unable to create device "
-		       "for rpi_backlight; errno = %ld\n",
-		       PTR_ERR(rpi_backlight_device));
-		rpi_backlight_device = NULL;
-	} else {
-		//init_device
-		ret = device_create_file(rpi_backlight_device, &dev_attr_brightness);
-		if (ret != 0) {
-			dev_err(&client->dev, "Failed to create brightness sysfs files %d\n", ret);
-			return ret;
-		}
-	}
-
 	return 0;
 
 error:

drivers/video/backlight/backlight.c

@@ -124,7 +124,6 @@ static void backlight_generate_event(struct backlight_device *bd,
 	sysfs_notify(&bd->dev.kobj, NULL, "actual_brightness");
 }
 
-#ifndef CONFIG_TINKER_MCU
 static ssize_t bl_power_show(struct device *dev, struct device_attribute *attr,
 		char *buf)
 {
@@ -160,6 +159,7 @@ static ssize_t bl_power_store(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RW(bl_power);
 
+#ifndef CONFIG_TINKER_MCU
 static ssize_t brightness_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
@@ -207,6 +207,32 @@ static ssize_t brightness_store(struct device *dev,
 
 	return rc ? rc : count;
 }
+#else
+extern int tinker_mcu_set_bright(int bright);
+extern int tinker_mcu_get_brightness(void);
+static ssize_t brightness_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	int level;
+
+	level = tinker_mcu_get_brightness();
+
+    return sprintf(buf, "%d\n", level);
+}
+
+static ssize_t brightness_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)) {
+		pr_err("Invalid value for backlight setting, value = %d\n", value);
+	} else
+		tinker_mcu_set_bright(value);
+
+	return strnlen(buf, count);
+}
+#endif
 static DEVICE_ATTR_RW(brightness);
 
 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
@@ -243,10 +269,8 @@ static ssize_t actual_brightness_show(struct device *dev,
 	return rc;
 }
 static DEVICE_ATTR_RO(actual_brightness);
-#endif
 
 struct class *backlight_class;
-EXPORT_SYMBOL(backlight_class);
 
 #ifdef CONFIG_PM_SLEEP
 static int backlight_suspend(struct device *dev)
@@ -288,13 +312,11 @@ static void bl_device_release(struct device *dev)
 }
 
 static struct attribute *bl_device_attrs[] = {
-#ifndef CONFIG_TINKER_MCU
 	&dev_attr_bl_power.attr,
 	&dev_attr_brightness.attr,
 	&dev_attr_actual_brightness.attr,
 	&dev_attr_max_brightness.attr,
 	&dev_attr_type.attr,
-#endif
 	NULL,
 };
 ATTRIBUTE_GROUPS(bl_device);

include/linux/backlight.h

@@ -47,7 +47,6 @@ enum backlight_notification {
 
 struct backlight_device;
 struct fb_info;
-extern struct class *backlight_class;
 
 struct backlight_ops {
 	unsigned int options;