From 6ca187abb2fc1a52b2a8e0422f3ffce2e3bb7ad0 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Thu, 15 Jan 2009 05:53:18 -0300 Subject: V4L/DVB (10251): cx25840: add comments explaining what the init() does. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/cx25840/cx25840-core.c | 10 ++++++++++ include/media/cx25840.h | 12 ++++++++++++ 2 files changed, 22 insertions(+) diff --git a/drivers/media/video/cx25840/cx25840-core.c b/drivers/media/video/cx25840/cx25840-core.c index 25eb3bec9e5d..be467b4b9545 100644 --- a/drivers/media/video/cx25840/cx25840-core.c +++ b/drivers/media/video/cx25840/cx25840-core.c @@ -1101,6 +1101,16 @@ static void log_audio_status(struct i2c_client *client) /* ----------------------------------------------------------------------- */ +/* 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 db431d513f2f..2c3fbaa33f74 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, -- cgit v1.2.3