Commit d842a7cf authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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media: adv7842: enable reduced fps detection 



The pixelclock detection of the adv7842 is precise enough to detect
if the framerate is 60 Hz or 59.94 Hz (aka "reduced fps").

Implement this detection.

Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
parent 3ae17c66

drivers/media/i2c/adv7842.c

+9 −0
Original line number Diff line number Diff line
@@ -1525,6 +1525,7 @@ static void adv7842_fill_optional_dv_timings_fields(struct v4l2_subdev *sd, 
	v4l2_find_dv_timings_cap(timings, adv7842_get_dv_timings_cap(sd),

			is_digital_input(sd) ? 250000 : 1000000,

			adv7842_check_dv_timings, NULL);

	timings->bt.flags |= V4L2_DV_FL_CAN_DETECT_REDUCED_FPS;

}



static int adv7842_query_dv_timings(struct v4l2_subdev *sd,
@@ -1596,6 +1597,14 @@ static int adv7842_query_dv_timings(struct v4l2_subdev *sd, 
			bt->il_vbackporch = 0;

		}

		adv7842_fill_optional_dv_timings_fields(sd, timings);

		if ((timings->bt.flags & V4L2_DV_FL_CAN_REDUCE_FPS) &&

		    freq < bt->pixelclock) {

			u32 reduced_freq = ((u32)bt->pixelclock / 1001) * 1000;

			u32 delta_freq = abs(freq - reduced_freq);



			if (delta_freq < ((u32)bt->pixelclock - reduced_freq) / 2)

				timings->bt.flags |= V4L2_DV_FL_REDUCED_FPS;

		}

	} else {

		/* find format

		 * Since LCVS values are inaccurate [REF_03, p. 339-340],