media: Kconfig: cleanup VIDEO_DEV dependencies

media Kconfig has two entries associated to V4L API:
VIDEO_DEV and VIDEO_V4L2.

On Kernel 2.6.x, there were two V4L APIs, each one with its own flag.
VIDEO_DEV were meant to:
	1) enable Video4Linux and make its Kconfig options to appear;
	2) it makes the Kernel build the V4L core.

while VIDEO_V4L2 where used to distinguish between drivers that
implement the newer API and drivers that implemented the former one.

With time, such meaning changed, specially after the removal of
all V4L version 1 drivers.

At the current implementation, VIDEO_DEV only does (1): it enables
the media options related to V4L, that now has:

	menu "Video4Linux options"
		visible if VIDEO_DEV

	source "drivers/media/v4l2-core/Kconfig"
	endmenu

but it doesn't affect anymore the V4L core drivers.

The rationale is that the V4L2 core has a "soft" dependency
at the I2C bus, and now requires to select a number of other
Kconfig options:

	config VIDEO_V4L2
		tristate
		depends on (I2C || I2C=n) && VIDEO_DEV
		select RATIONAL
		select VIDEOBUF2_V4L2 if VIDEOBUF2_CORE
		default (I2C || I2C=n) && VIDEO_DEV

In the past, merging them would be tricky, but it seems that it is now
possible to merge those symbols, in order to simplify V4L dependencies.

Let's keep VIDEO_DEV, as this one is used on some make *defconfig
configurations.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> # for meson-vdec & meson-ge2d
Acked-by: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/input/rmi4/Kconfig

@@ -110,7 +110,7 @@ config RMI4_F3A
 
 config RMI4_F54
 	bool "RMI4 Function 54 (Analog diagnostics)"
-	depends on VIDEO_V4L2=y || (RMI4_CORE=m && VIDEO_V4L2=m)
+	depends on VIDEO_DEV=y || (RMI4_CORE=m && VIDEO_DEV=m)
 	select VIDEOBUF2_VMALLOC
 	select RMI4_F55
 	help

drivers/input/touchscreen/Kconfig

@@ -131,7 +131,7 @@ config TOUCHSCREEN_ATMEL_MXT
 config TOUCHSCREEN_ATMEL_MXT_T37
 	bool "Support T37 Diagnostic Data"
 	depends on TOUCHSCREEN_ATMEL_MXT
-	depends on VIDEO_V4L2=y || (TOUCHSCREEN_ATMEL_MXT=m && VIDEO_V4L2=m)
+	depends on VIDEO_DEV=y || (TOUCHSCREEN_ATMEL_MXT=m && VIDEO_DEV=m)
 	select VIDEOBUF2_VMALLOC
 	help
 	  Say Y here if you want support to output data from the T37
@@ -1252,7 +1252,7 @@ config TOUCHSCREEN_SUN4I
 config TOUCHSCREEN_SUR40
 	tristate "Samsung SUR40 (Surface 2.0/PixelSense) touchscreen"
 	depends on USB && MEDIA_USB_SUPPORT && HAS_DMA
-	depends on VIDEO_V4L2
+	depends on VIDEO_DEV
 	select VIDEOBUF2_DMA_SG
 	help
 	  Say Y here if you want support for the Samsung SUR40 touchscreen

drivers/media/Kconfig

@@ -160,6 +160,9 @@ menu "Media core support"
 config VIDEO_DEV
 	tristate "Video4Linux core"
 	default MEDIA_CAMERA_SUPPORT || MEDIA_ANALOG_TV_SUPPORT || MEDIA_RADIO_SUPPORT || MEDIA_SDR_SUPPORT || MEDIA_PLATFORM_SUPPORT || MEDIA_TEST_SUPPORT
+	depends on (I2C || I2C=n)
+	select RATIONAL
+	select VIDEOBUF2_V4L2 if VIDEOBUF2_CORE
 	help
 	  Enables the V4L2 API, used by cameras, analog TV, video grabbers,
 	  radio devices and by some input devices.

drivers/media/common/saa7146/Kconfig

@@ -5,6 +5,6 @@ config VIDEO_SAA7146
 
 config VIDEO_SAA7146_VV
 	tristate
-	depends on VIDEO_V4L2
+	depends on VIDEO_DEV
 	select VIDEOBUF_DMA_SG
 	select VIDEO_SAA7146

drivers/media/dvb-core/Kconfig

@@ -6,7 +6,7 @@
 config DVB_MMAP
 	bool "Enable DVB memory-mapped API (EXPERIMENTAL)"
 	depends on DVB_CORE
-	depends on VIDEO_V4L2=y || VIDEO_V4L2=DVB_CORE
+	depends on VIDEO_DEV=y || VIDEO_DEV=DVB_CORE
 	select VIDEOBUF2_VMALLOC
 	help
 	  This option enables DVB experimental memory-mapped API, which

drivers/media/dvb-frontends/Kconfig

@@ -510,7 +510,7 @@ config DVB_RTL2832
 
 config DVB_RTL2832_SDR
 	tristate "Realtek RTL2832 SDR"
-	depends on DVB_CORE && I2C && I2C_MUX && VIDEO_V4L2 && MEDIA_SDR_SUPPORT && USB
+	depends on DVB_CORE && I2C && I2C_MUX && VIDEO_DEV && MEDIA_SDR_SUPPORT && USB
 	select DVB_RTL2832
 	select VIDEOBUF2_VMALLOC
 	default m if !MEDIA_SUBDRV_AUTOSELECT
@@ -681,7 +681,7 @@ config DVB_AU8522_DTV
 
 config DVB_AU8522_V4L
 	tristate "Auvitek AU8522 based ATV demod"
-	depends on VIDEO_V4L2 && DVB_CORE && I2C
+	depends on VIDEO_DEV && DVB_CORE && I2C
 	select DVB_AU8522
 	default m if !MEDIA_SUBDRV_AUTOSELECT
 	help