media: ad5820: Add support for ad5821 and ad5823

According to the datasheet, both AD5821 and AD5820 share a compatible
register-set:
http://www.analog.com/media/en/technical-documentation/data-sheets/AD5821.pdf

Some camera modules also refer that AD5823 is a replacement of AD5820:
https://download.kamami.com/p564094-OV8865_DS.pdfSuggested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Ricardo Ribalda Delgado <ribalda@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/i2c/ad5820.c

@@ -25,8 +25,6 @@
 #include <media/v4l2-device.h>
 #include <media/v4l2-subdev.h>
 
-#define AD5820_NAME		"ad5820"
-
 /* Register definitions */
 #define AD5820_POWER_DOWN		(1 << 15)
 #define AD5820_DAC_SHIFT		4
@@ -359,13 +357,17 @@ static int ad5820_remove(struct i2c_client *client)
 }
 
 static const struct i2c_device_id ad5820_id_table[] = {
-	{ AD5820_NAME, 0 },
+	{ "ad5820", 0 },
+	{ "ad5821", 0 },
+	{ "ad5823", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, ad5820_id_table);
 
 static const struct of_device_id ad5820_of_table[] = {
 	{ .compatible = "adi,ad5820" },
+	{ .compatible = "adi,ad5821" },
+	{ .compatible = "adi,ad5823" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, ad5820_of_table);
@@ -374,7 +376,7 @@ static SIMPLE_DEV_PM_OPS(ad5820_pm, ad5820_suspend, ad5820_resume);
 
 static struct i2c_driver ad5820_i2c_driver = {
 	.driver		= {
-		.name	= AD5820_NAME,
+		.name	= "ad5820",
 		.pm	= &ad5820_pm,
 		.of_match_table = ad5820_of_table,
 	},