V4L/DVB (7115): Fix bug #9833: regression when compiling V4L without I2C

Adrian Bunk reported:

> > Commit 8ffbc65594 causes the following
> > compile error with CONFIG_VIDEO_DEV=y/m, CONFIG_I2C=n:
> >
> > <--  snip  -->
> >
> > ...
> >   MODPOST 26 modules
> > ERROR: "i2c_attach_client" [drivers/media/video/v4l2-common.ko] undefined!
> > make[2]: *** [__modpost] Error 1
> >
> > <--  snip  -->

...

And what should happen if CONFIG_VIDEO_DEV=y, CONFIG_I2C=m?

CC: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/Kconfig

@@ -25,6 +25,11 @@ config VIDEO_DEV
 	  To compile this driver as a module, choose M here: the
 	  module will be called videodev.
 
+config VIDEO_V4L2_COMMON
+	tristate
+	depends on (I2C || I2C=n) && VIDEO_DEV
+	default (I2C || I2C=n) && VIDEO_DEV
+
 config VIDEO_V4L1
 	bool "Enable Video For Linux API 1 (DEPRECATED)"
 	depends on VIDEO_DEV

drivers/media/video/Makefile

@@ -10,8 +10,9 @@ msp3400-objs	:=	msp3400-driver.o msp3400-kthreads.o
 
 stkwebcam-objs	:=	stk-webcam.o stk-sensor.o
 
-obj-$(CONFIG_VIDEO_DEV) += videodev.o v4l2-common.o compat_ioctl32.o \
-			   v4l2-int-device.o
+obj-$(CONFIG_VIDEO_DEV) += videodev.o compat_ioctl32.o v4l2-int-device.o
+
+obj-$(CONFIG_VIDEO_V4L2_COMMON) += v4l2-common.o
 
 ifeq ($(CONFIG_VIDEO_V4L1_COMPAT),y)
   obj-$(CONFIG_VIDEO_DEV) += v4l1-compat.o

drivers/media/video/v4l2-common.c

@@ -973,6 +973,18 @@ u32 v4l2_ctrl_next(const u32 * const * ctrl_classes, u32 id)
 	return **ctrl_classes;
 }
 
+int v4l2_chip_match_host(u32 match_type, u32 match_chip)
+{
+	switch (match_type) {
+	case V4L2_CHIP_MATCH_HOST:
+		return match_chip == 0;
+	default:
+		return 0;
+	}
+}
+EXPORT_SYMBOL(v4l2_chip_match_host);
+
+#if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
 int v4l2_chip_match_i2c_client(struct i2c_client *c, u32 match_type, u32 match_chip)
 {
 	switch (match_type) {
@@ -984,6 +996,7 @@ int v4l2_chip_match_i2c_client(struct i2c_client *c, u32 match_type, u32 match_c
 		return 0;
 	}
 }
+EXPORT_SYMBOL(v4l2_chip_match_i2c_client);
 
 int v4l2_chip_ident_i2c_client(struct i2c_client *c, struct v4l2_chip_ident *chip,
 		u32 ident, u32 revision)
@@ -1000,16 +1013,7 @@ int v4l2_chip_ident_i2c_client(struct i2c_client *c, struct v4l2_chip_ident *chi
 	}
 	return 0;
 }
-
-int v4l2_chip_match_host(u32 match_type, u32 match_chip)
-{
-	switch (match_type) {
-	case V4L2_CHIP_MATCH_HOST:
-		return match_chip == 0;
-	default:
-		return 0;
-	}
-}
+EXPORT_SYMBOL(v4l2_chip_ident_i2c_client);
 
 /* ----------------------------------------------------------------- */
 
@@ -1038,6 +1042,8 @@ int v4l2_i2c_attach(struct i2c_adapter *adapter, int address, struct i2c_driver
 	}
 	return err != -ENOMEM ? 0 : err;
 }
+EXPORT_SYMBOL(v4l2_i2c_attach);
+#endif
 
 /* ----------------------------------------------------------------- */
 
@@ -1061,15 +1067,3 @@ EXPORT_SYMBOL(v4l2_ctrl_get_menu);
 EXPORT_SYMBOL(v4l2_ctrl_query_menu);
 EXPORT_SYMBOL(v4l2_ctrl_query_fill);
 EXPORT_SYMBOL(v4l2_ctrl_query_fill_std);
-
-EXPORT_SYMBOL(v4l2_chip_match_i2c_client);
-EXPORT_SYMBOL(v4l2_chip_ident_i2c_client);
-EXPORT_SYMBOL(v4l2_chip_match_host);
-
-EXPORT_SYMBOL(v4l2_i2c_attach);
-
-/*
- * Local variables:
- * c-basic-offset: 8
- * End:
- */