V4L/DVB (10251): cx25840: add comments explaining what the init() does.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/cx25840/cx25840-core.c b/drivers/media/video/cx25840/cx25840-core.c
index 25eb3bec..be467b4 100644
--- a/drivers/media/video/cx25840/cx25840-core.c
+++ b/drivers/media/video/cx25840/cx25840-core.c
@@ -1101,6 +1101,16 @@
/* ----------------------------------------------------------------------- */
+/* This init operation must be called to load the driver's firmware.
+ Without this the audio standard detection will fail and you will
+ only get mono.
+
+ Since loading the firmware is often problematic when the driver is
+ compiled into the kernel I recommend postponing calling this function
+ until the first open of the video device. Another reason for
+ postponing it is that loading this firmware takes a long time (seconds)
+ due to the slow i2c bus speed. So it will speed up the boot process if
+ you can avoid loading the fw as long as the video device isn't used. */
static int cx25840_init(struct v4l2_subdev *sd, u32 val)
{
struct cx25840_state *state = to_state(sd);
diff --git a/include/media/cx25840.h b/include/media/cx25840.h
index db431d5..2c3fbaa 100644
--- a/include/media/cx25840.h
+++ b/include/media/cx25840.h
@@ -21,6 +21,18 @@
#ifndef _CX25840_H_
#define _CX25840_H_
+/* Note that the cx25840 driver requires that the bridge driver calls the
+ v4l2_subdev's init operation in order to load the driver's firmware.
+ Without this the audio standard detection will fail and you will
+ only get mono.
+
+ Since loading the firmware is often problematic when the driver is
+ compiled into the kernel I recommend postponing calling this function
+ until the first open of the video device. Another reason for
+ postponing it is that loading this firmware takes a long time (seconds)
+ due to the slow i2c bus speed. So it will speed up the boot process if
+ you can avoid loading the fw as long as the video device isn't used. */
+
enum cx25840_video_input {
/* Composite video inputs In1-In8 */
CX25840_COMPOSITE1 = 1,
