[PATCH v6 33/39] media: imx: csi: Avoid faulty sensor frames at stream start
From: slongerbeam@gmail.com (Steve Longerbeam)
Date: 2017-03-28 00:42:54
Also in:
linux-devicetree, linux-media, lkml
Subsystem:
media drivers for freescale imx, media input infrastructure (v4l/dvb), staging subsystem, the rest · Maintainers:
Steve Longerbeam, Philipp Zabel, Mauro Carvalho Chehab, Greg Kroah-Hartman, Linus Torvalds
If the attached sensor reports faulty frames at stream start via g_skip_frames callback, add a delay to avoid them before enabling the CSI hardware. Especially for sensors with a bt.656 interface, any shifts in the SAV/EAV sync codes will cause the CSI to lose vert/horiz sync. Signed-off-by: Steve Longerbeam <redacted> --- drivers/staging/media/imx/imx-media-csi.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)
diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c
index d9c3a3b..8597d7e 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c@@ -9,6 +9,7 @@ * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ +#include <linux/delay.h> #include <linux/gcd.h> #include <linux/interrupt.h> #include <linux/module.h>
@@ -591,6 +592,7 @@ static int csi_setup(struct csi_priv *priv) static int csi_start(struct csi_priv *priv) { + u32 bad_frames = 0; int ret; if (!priv->sensor) {
@@ -598,6 +600,25 @@ static int csi_start(struct csi_priv *priv) return -EINVAL; } + ret = v4l2_subdev_call(priv->sensor->sd, sensor, + g_skip_frames, &bad_frames); + if (!ret && bad_frames) { + struct v4l2_fract *fi = &priv->frame_interval; + u32 delay_usec; + + /* + * This sensor has bad frames when it is turned on, + * add a delay to avoid them before enabling the CSI + * hardware. Especially for sensors with a bt.656 interface, + * any shifts in the SAV/EAV sync codes will cause the CSI + * to lose vert/horiz sync. + */ + delay_usec = DIV_ROUND_UP_ULL( + (u64)USEC_PER_SEC * fi->numerator * bad_frames, + fi->denominator); + usleep_range(delay_usec, delay_usec + 1000); + } + if (priv->dest == IPU_CSI_DEST_IDMAC) { ret = csi_idmac_start(priv); if (ret)
--
2.7.4