media: ov772x: make set_fmt() and s_frame_interval() return -EBUSY while streaming

The ov772x driver is going to offer a V4L2 sub-device interface, so
changing the output data format and the frame interval on this sub-device
can be made anytime.  However, these requests are preferred to fail while
the video stream on the device is active.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
index d380e75..9ff8e60 100644 (file)
--- a/drivers/media/i2c/ov772x.c
+++ b/drivers/media/i2c/ov772x.c
@@ -424,9 +424,10 @@ struct ov772x_priv {
        /* band_filter = COM8[5] ? 256 - BDBASE : 0 */
        struct v4l2_ctrl                 *band_filter_ctrl;
        unsigned int                      fps;
-       /* lock to protect power_count */
+       /* lock to protect power_count and streaming */
        struct mutex                      lock;
        int                               power_count;
+       int                               streaming;
 #ifdef CONFIG_MEDIA_CONTROLLER
        struct media_pad pad;
 #endif
@@ -603,18 +604,28 @@ static int ov772x_s_stream(struct v4l2_subdev *sd, int enable)
 {
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        struct ov772x_priv *priv = to_ov772x(sd);
+       int ret = 0;
 
-       if (!enable) {
-               ov772x_mask_set(client, COM2, SOFT_SLEEP_MODE, SOFT_SLEEP_MODE);
-               return 0;
-       }
+       mutex_lock(&priv->lock);
 
-       ov772x_mask_set(client, COM2, SOFT_SLEEP_MODE, 0);
+       if (priv->streaming == enable)
+               goto done;
 
-       dev_dbg(&client->dev, "format %d, win %s\n",
-               priv->cfmt->code, priv->win->name);
+       ret = ov772x_mask_set(client, COM2, SOFT_SLEEP_MODE,
+                             enable ? 0 : SOFT_SLEEP_MODE);
+       if (ret)
+               goto done;
 
-       return 0;
+       if (enable) {
+               dev_dbg(&client->dev, "format %d, win %s\n",
+                       priv->cfmt->code, priv->win->name);
+       }
+       priv->streaming = enable;
+
+done:
+       mutex_unlock(&priv->lock);
+
+       return ret;
 }
 
 static unsigned int ov772x_select_fps(struct ov772x_priv *priv,
@@ -743,9 +754,15 @@ static int ov772x_s_frame_interval(struct v4l2_subdev *sd,
        unsigned int fps;
        int ret = 0;
 
+       mutex_lock(&priv->lock);
+
+       if (priv->streaming) {
+               ret = -EBUSY;
+               goto error;
+       }
+
        fps = ov772x_select_fps(priv, tpf);
 
-       mutex_lock(&priv->lock);
        /*
         * If the device is not powered up by the host driver do
         * not apply any changes to H/W at this time. Instead
@@ -1222,6 +1239,12 @@ static int ov772x_set_fmt(struct v4l2_subdev *sd,
        }
 
        mutex_lock(&priv->lock);
+
+       if (priv->streaming) {
+               ret = -EBUSY;
+               goto error;
+       }
+
        /*
         * If the device is not powered up by the host driver do
         * not apply any changes to H/W at this time. Instead