From: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
The MAX9286 can generate a framesync signal to synchronize the cameras,
using an internal timer. Support this mode of operation and configure it
through the .s_frameinterval() operation. If the frame interval is not
0, framesync is switched to manual mode with the specified interval,
otherwise automatic mode is used.
Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---
drivers/media/i2c/max9286.c | 66 +++++++++++++++++++++++++++++++++++--
1 file changed, 63 insertions(+), 3 deletions(-)
diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
index fa2f6a823fe6..dce1146635d2 100644
--- a/drivers/media/i2c/max9286.c
+++ b/drivers/media/i2c/max9286.c
@@ -174,6 +174,7 @@ struct max9286_priv {
struct v4l2_ctrl *pixelrate;
struct v4l2_mbus_framefmt fmt[MAX9286_N_SINKS];
+ struct v4l2_fract interval;
/* Protects controls and fmt structures */
struct mutex mutex;
@@ -474,6 +475,37 @@ static int max9286_check_config_link(struct max9286_priv *priv,
return 0;
}
+static void max9286_set_fsync_period(struct max9286_priv *priv)
+{
+ u32 fsync;
+
+ if (!priv->interval.numerator || !priv->interval.denominator) {
+ /*
+ * Special case, a null interval enables automatic FRAMESYNC
+ * mode. FRAMESYNC is taken from the slowest link.
+ */
+ max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ |
+ MAX9286_FSYNCMETH_AUTO);
+ return;
+ }
+
+ /*
+ * Manual FRAMESYNC
+ *
+ * The FRAMESYNC generator is configured with a period expressed as a
+ * number of PCLK periods, which runs at 75MHz.
+ */
+ fsync = div_u64(75000000ULL * priv->interval.numerator,
+ priv->interval.denominator);
+
+ max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_OUT |
+ MAX9286_FSYNCMETH_MANUAL);
+
+ max9286_write(priv, 0x06, (fsync >> 0) & 0xff);
+ max9286_write(priv, 0x07, (fsync >> 8) & 0xff);
+ max9286_write(priv, 0x08, (fsync >> 16) & 0xff);
+}
+
/* -----------------------------------------------------------------------------
* V4L2 Subdev
*/
@@ -656,6 +688,8 @@ static int max9286_s_stream(struct v4l2_subdev *sd, int enable)
int ret;
if (enable) {
+ max9286_set_fsync_period(priv);
+
/*
* The frame sync between cameras is transmitted across the
* reverse channel as GPIO. We must open all channels while
@@ -715,6 +749,32 @@ static int max9286_s_stream(struct v4l2_subdev *sd, int enable)
return 0;
}
+static int max9286_g_frame_interval(struct v4l2_subdev *sd,
+ struct v4l2_subdev_frame_interval *interval)
+{
+ struct max9286_priv *priv = sd_to_max9286(sd);
+
+ if (interval->pad == MAX9286_SRC_PAD)
+ return -EINVAL;
+
+ interval->interval = priv->interval;
+
+ return 0;
+}
+
+static int max9286_s_frame_interval(struct v4l2_subdev *sd,
+ struct v4l2_subdev_frame_interval *interval)
+{
+ struct max9286_priv *priv = sd_to_max9286(sd);
+
+ if (interval->pad == MAX9286_SRC_PAD)
+ return -EINVAL;
+
+ priv->interval = interval->interval;
+
+ return 0;
+}
+
static int max9286_enum_mbus_code(struct v4l2_subdev *sd,
struct v4l2_subdev_state *sd_state,
struct v4l2_subdev_mbus_code_enum *code)
@@ -806,6 +866,8 @@ static int max9286_get_fmt(struct v4l2_subdev *sd,
static const struct v4l2_subdev_video_ops max9286_video_ops = {
.s_stream = max9286_s_stream,
+ .g_frame_interval = max9286_g_frame_interval,
+ .s_frame_interval = max9286_s_frame_interval,
};
static const struct v4l2_subdev_pad_ops max9286_pad_ops = {
@@ -998,9 +1060,7 @@ static int max9286_setup(struct max9286_priv *priv)
MAX9286_CSILANECNT(priv->csi2_data_lanes) |
MAX9286_DATATYPE_YUV422_8BIT);
- /* Automatic: FRAMESYNC taken from the slowest Link. */
- max9286_write(priv, 0x01, MAX9286_FSYNCMODE_INT_HIZ |
- MAX9286_FSYNCMETH_AUTO);
+ max9286_set_fsync_period(priv);
/* Enable HS/VS encoding, use D14/15 for HS/VS, invert VS. */
max9286_write(priv, 0x0c, MAX9286_HVEN | MAX9286_INVVS |
--
Regards,
Laurent Pinchart
