V4L/DVB (10190): cx88: Fix some Kbuild troubles

As Randy Dunlap <randy.dunlap@oracle.com> reported, cx88 has some compilation issues:

drivers/built-in.o: In function `cx88_call_i2c_clients':
(.text+0x20af17): undefined reference to `videobuf_dvb_get_frontend'
drivers/built-in.o: In function `cx8802_probe':
cx88-mpeg.c:(.devinit.text+0x268c4): undefined reference to `videobuf_dvb_alloc_frontend'
cx88-mpeg.c:(.devinit.text+0x268ea): undefined reference to `videobuf_dvb_dealloc_frontends'

With those configs:

CONFIG_VIDEO_CX88=y
CONFIG_VIDEO_CX88_BLACKBIRD=y
CONFIG_VIDEO_CX88_DVB=m
CONFIG_DVB_CORE=m

After carefully examining the code, with the current code, several cx88 drivers
(cx8800, cx8802, cx88_dvb and cx88_blackbird) should be compiled as a module,
if one of them is marked as such. Just fixing Kconfig could create a very complex
set of rules. Also, this hides a problem with the current approach where the dvb
functionality weren't confined inside dvb module.

What happens is that:
	- cx88-i2c (part of cx8800) has some special rules if DVB;
	- cx88-mpeg (cx8802 module) has also part of DVB init code;
	- cx88-dvb has the rest of the dvb code;
	- cx88-blackbird can be used with cx88-mpeg, having cx88-dvb or not.

So, instead of doing some tricks at Kconfig and wait for a next breakage,
this patch moves the dvb code inside cx88-i2c and cx88-mpeg into cx88-dvb.

Another problem is that cx8802 were being compiled, even without cx88-dvb
and cx88-blackbird modules.

While on this code, let's fix also a reported problem:
http://www.linuxtv.org/pipermail/linux-dvb/2009-January/031225.html

A solution for the issue were proposed here:
http://www.mail-archive.com/linux-media@vger.kernel.org/msg00021.html

Thanks to Randy, Andy, Gregoire and Thomas for helping us to detect
and solve the issues.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/media/video/cx88/cx88.h b/drivers/media/video/cx88/cx88.h
index eb9ce30dc5e6..60a8b3187f14 100644
--- a/drivers/media/video/cx88/cx88.h
+++ b/drivers/media/video/cx88/cx88.h
@@ -302,6 +302,7 @@ struct cx88_dmaqueue {
         struct btcx_riscmem    stopper;
         u32                    count;
 };
+struct cx88_core;
 
 struct cx88_core {
         struct list_head           devlist;
@@ -334,7 +335,8 @@ struct cx88_core {
 
         /* config info -- dvb */
 #if defined(CONFIG_VIDEO_CX88_DVB) || defined(CONFIG_VIDEO_CX88_DVB_MODULE)
-        int                        (*prev_set_voltage)(struct dvb_frontend* fe, fe_sec_voltage_t voltage);
+        int                        (*prev_set_voltage)(struct dvb_frontend *fe, fe_sec_voltage_t voltage);
+        void                       (*gate_ctrl)(struct cx88_core  *core, int open);
 #endif
 
         /* state info */