[PATCH/RFC v2 05/15] rcar-csi2: count usage for each source pad

[Niklas Söderlund]

The R-Car CSI-2 hardware can output the same virtual channel
simultaneously to more then one R-Car VIN. For this reason we need to
move the usage counting from the global device to each source pad.

If a source pads usage count go from 0 to 1 we need to signal that a new
stream should start, likewise if it go from 1 to 0 we need to stop a
stream. At the same time we only want to start or stop the R-Car
CSI-2 device only on the first or last stream.

Signed-off-by: Niklas Söderlund <niklas.soderlund+rene...@ragnatech.se>
---
 drivers/media/platform/rcar-vin/rcar-csi2.c | 38 +++++++++++++++++++++++------
 1 file changed, 30 insertions(+), 8 deletions(-)

diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c 
b/drivers/media/platform/rcar-vin/rcar-csi2.c
index 8ce0bfeef1113f9c..e0f56cc3d25179a9 100644
--- a/drivers/media/platform/rcar-vin/rcar-csi2.c
+++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
@@ -328,6 +328,14 @@ enum rcar_csi2_pads {
        NR_OF_RCAR_CSI2_PAD,
 };
 
+static int rcar_csi2_pad_to_vc(unsigned int pad)
+{
+       if (pad < RCAR_CSI2_SOURCE_VC0 || pad > RCAR_CSI2_SOURCE_VC3)
+               return -EINVAL;
+
+       return pad - RCAR_CSI2_SOURCE_VC0;
+}
+
 struct rcar_csi2_info {
        const struct phypll_hsfreqrange *hsfreqrange;
        const struct phtw_testdin_data *testdin_data;
@@ -350,7 +358,7 @@ struct rcar_csi2 {
        struct v4l2_mbus_framefmt mf;
 
        struct mutex lock;
-       int stream_count;
+       int stream_count[4];
 
        unsigned short lanes;
        unsigned char lane_swap[4];
@@ -630,7 +638,13 @@ static int rcar_csi2_s_stream(struct v4l2_subdev *sd, 
unsigned int pad,
 {
        struct rcar_csi2 *priv = sd_to_csi2(sd);
        struct v4l2_subdev *nextsd;
-       int ret;
+       unsigned int i, count = 0;
+       int ret, vc;
+
+       /* Only allow stream control on source pads and valid vc */
+       vc = rcar_csi2_pad_to_vc(pad);
+       if (vc < 0)
+               return vc;
 
        /* Only one stream on each source pad */
        if (stream != 0)
@@ -642,7 +656,10 @@ static int rcar_csi2_s_stream(struct v4l2_subdev *sd, 
unsigned int pad,
        if (ret)
                goto out;
 
-       if (enable && priv->stream_count == 0) {
+       for (i = 0; i < 4; i++)
+               count += priv->stream_count[i];
+
+       if (enable && count == 0) {
                pm_runtime_get_sync(priv->dev);
 
                ret = rcar_csi2_start(priv);
@@ -650,20 +667,23 @@ static int rcar_csi2_s_stream(struct v4l2_subdev *sd, 
unsigned int pad,
                        pm_runtime_put(priv->dev);
                        goto out;
                }
+       } else if (!enable && count == 1) {
+               rcar_csi2_stop(priv);
+               pm_runtime_put(priv->dev);
+       }
 
+       if (enable && priv->stream_count[vc] == 0) {
                ret = v4l2_subdev_call(nextsd, video, s_stream, 1);
                if (ret) {
                        rcar_csi2_stop(priv);
                        pm_runtime_put(priv->dev);
                        goto out;
                }
-       } else if (!enable && priv->stream_count == 1) {
-               rcar_csi2_stop(priv);
+       } else if (!enable && priv->stream_count[vc] == 1) {
                ret = v4l2_subdev_call(nextsd, video, s_stream, 0);
-               pm_runtime_put(priv->dev);
        }
 
-       priv->stream_count += enable ? 1 : -1;
+       priv->stream_count[vc] += enable ? 1 : -1;
 out:
        mutex_unlock(&priv->lock);
 
@@ -919,7 +939,9 @@ static int rcar_csi2_probe(struct platform_device *pdev)
        priv->dev = &pdev->dev;
 
        mutex_init(&priv->lock);
-       priv->stream_count = 0;
+
+       for (i = 0; i < 4; i++)
+               priv->stream_count[i] = 0;
 
        ret = rcar_csi2_probe_resources(priv, pdev);
        if (ret) {
-- 
2.15.1