[media] cx231xx: remember status of i2c port_3 switch

This is used later for is_tuner function that switches i2c behaviour for
some tuners.

[mchehab@osg.samsung.com: Fix CodingStyle on a multi-line comment]
Signed-off-by: Matthias Schwarzott <zzam@gentoo.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/usb/cx231xx/cx231xx-avcore.c

@@ -1272,6 +1272,14 @@ int cx231xx_enable_i2c_port_3(struct cx231xx *dev, bool is_port_3)
 
 	if (dev->board.dont_use_port_3)
 		is_port_3 = false;
+
+	/*
+	 * Should this code check dev->port_3_switch_enabled first
+	 * to skip unnecessary reading of the register?
+	 * If yes, the flag dev->port_3_switch_enabled must be initialized
+	 * correctly.
+	 */
+
 	status = cx231xx_read_ctrl_reg(dev, VRT_GET_REGISTER,
 				       PWR_CTL_EN, value, 4);
 	if (status < 0)
@@ -1294,6 +1302,10 @@ int cx231xx_enable_i2c_port_3(struct cx231xx *dev, bool is_port_3)
 	status = cx231xx_write_ctrl_reg(dev, VRT_SET_REGISTER,
 					PWR_CTL_EN, value, 4);
 
+	/* remember status of the switch for usage in is_tuner */
+	if (status >= 0)
+		dev->port_3_switch_enabled = is_port_3;
+
 	return status;
 
 }

drivers/media/usb/cx231xx/cx231xx.h

@@ -629,6 +629,7 @@ struct cx231xx {
 	/* I2C adapters: Master 1 & 2 (External) & Master 3 (Internal only) */
 	struct cx231xx_i2c i2c_bus[3];
 	unsigned int xc_fw_load_done:1;
+	unsigned int port_3_switch_enabled:1;
 	/* locks */
 	struct mutex gpio_i2c_lock;
 	struct mutex i2c_lock;