media: i2c: ov9281: Use frame period for sleep

This only applies to an ov9281 configured as an fsync slave.

We need to sleep at least as long as the frame sampling period after
making the fsync slave start streaming (we are assuming that the fsync
master is already started and is generating the fsin signal).

Previously, we were hardcoding the time to sleep based on a frame rate
of 120fps.  Instead, calculate the frame sampling period based on our
frame length setting.

Bug 1982522

Change-Id: I7d5c99c59e3eaf6a5016a3de02fc89e5b769b0aa
Signed-off-by: Andrew Chew <achew@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1570497
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: svccoveritychecker <svccoveritychecker@nvidia.com>
Reviewed-by: Xia Yang <xiay@nvidia.com>
Reviewed-by: Raymond Poudrier <rapoudrier@nvidia.com>
GVS: Gerrit_Virtual_Submit

1 files changed, 10 insertions, 3 deletions

diff --git a/drivers/media/i2c/ov9281.c b/drivers/media/i2c/ov9281.c
index 6c17983cb..2e505cb8a 100644
--- a/drivers/media/i2c/ov9281.c
+++ b/drivers/media/i2c/ov9281.c
@@ -90,6 +90,7 @@
 #define OV9281_DEFAULT_FRAME_LENGTH     0x071C
 #define OV9281_MIN_FRAME_LENGTH         0x0001
 #define OV9281_MAX_FRAME_LENGTH         0xFFFF
+#define OV9281_FRAME_LENGTH_1SEC        (0x40d * 120) /* TODO: try to calc */
 
 #define OV9281_MIN_EXPOSURE_COARSE      0x00000001
 #define OV9281_MAX_EXPOSURE_COARSE      0x000FFFFF
@@ -124,6 +125,7 @@ struct ov9281 {
 
         s32                             group_hold_prev;
         bool                            group_hold_en;
+        int                             frame_period_ms;
         struct regmap                   *regmap;
         struct camera_common_data       *s_data;
         struct camera_common_pdata      *pdata;
@@ -467,6 +469,11 @@ static int ov9281_set_frame_length(struct ov9281 *priv, s32 val)
         if (err)
                 goto fail;
 
+        priv->frame_period_ms = (frame_length * 1000) /
+                                OV9281_FRAME_LENGTH_1SEC;
+        dev_dbg(&priv->i2c_client->dev,
+                 "%s: frame_period_ms: %d\n", __func__, priv->frame_period_ms);
+
         return 0;
 
 fail:
@@ -702,11 +709,11 @@ static int ov9281_s_stream(struct v4l2_subdev *sd, int enable)
          * camera host.  So, after starting streaming, we assume fsync
          * master has already been told to start streaming, and we wait some
          * amount of time in order to skip the possible short frame.  The
-         * length of time to wait should be at least our sample period.
-         * Assume worse case of 120fps (8.3ms), and add a bit more.
+         * length of time to wait should be at least our frame period.
+         * Add a little bit extra as a safety margin.
          */
         if (priv->fsync == OV9281_FSYNC_SLAVE)
-                msleep_range(10);
+                msleep_range(priv->frame_period_ms + 10);
 
         return 0;