media: docs: move driver-specific info to driver-api

Those documents don't really describe the driver API.

Instead, they contain development-specific information.

Yet, as the main index file describes the content of it as:

"how specific kernel subsystems work
from the point of view of a kernel developer"

It seems to be the better fit.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation version 2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 135 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531081036.435762997@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

media: dvb: point to the location of the old README.dvb-usb file

This file got renamed, but the references still point to the
old place.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>

[media] dvb-usb-dibusb-mc-common: Add MODULE_LICENSE

dvb-usb-dibusb-mc-common is licensed under GPLv2, and if we don't say
so then it won't even load since it needs a GPL-only symbol.

Fixes: e91455a1495a ("[media] dvb-usb: split out common parts of dibusb")

Reported-by: Dominique Dumont <dod@debian.org>
Cc: stable@vger.kernel.org # 4.9+
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

[media] dvb-usb: remove another redundant #include <linux/kconfig.h>

Kernel source files need not include <linux/kconfig.h> explicitly
because the top Makefile forces to include it with:

-include $(srctree)/include/linux/kconfig.h

Remove another reduntdant include, that managed to sneak by commit
97139d4a6f26 ("treewide: remove redundant #include <linux/kconfig.h>").

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

[media] dvb-usb: split out common parts of dibusb

Tha ARM randconfig builds came up with another rare build failure
for the dib3000mc driver, when dvb-usb-dibusb-mb is built-in and
dib3000mc is a loadable module:

ERROR: "dibusb_dib3000mc_frontend_attach" [drivers/media/usb/dvb-usb/dvb-usb-nova-t-usb2.ko] undefined!
ERROR: "dibusb_dib3000mc_tuner_attach" [drivers/media/usb/dvb-usb/dvb-usb-nova-t-usb2.ko] undefined!

Apparently this used to be a valid configuration (build-time, not
run-time), but broke as part of a cleanup.

I tried reverting the cleanup, but saw that the code was still wrong
then. This tries to fix the code properly, by moving the problematic
functions into a new file that now is built as a loadable module or
built-in, whichever is correct for a particular configuration. It fixes
the regression as well as the runtime problem that already existed.

The new module dependency chain is now:

dvb-usb-{dibusb_mc,a800,dib0700,umt-010,gp8psk} dvb-usb-dibusb-mb
| | | |
dvb-usb-dibusb-mc-common | ___________| |
| | | | |
dib3000mc (frontend) | | | dib3000mb (frontend)
| | |
| | |
dvb-usb-dibusb-common

I have also checked the two other files that were changed in the original
cleanup, and found them to be correct in either version, so I do not
touch that part.

As this is a rather obscure bug, there is no need for backports.

Fixes: 028c70ff42783 ("[media] dvb-usb/dvb-usb-v2: use IS_ENABLED")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>