[PATCH v3 4/7] media: synopsys: Add support for multiple streams

[Guoniu Zhou]

The current driver only supports single stream operation. Add support
for multiple concurrent streams by tracking enabled streams with a
bitmask and only initializing the hardware once for the first stream.

This enables use cases such as surround view systems where multiple
camera streams need to be processed simultaneously through the same
CSI-2 receiver interface.

Reviewed-by: Frank Li <Frank.Li at nxp.com>
Signed-off-by: Guoniu Zhou <guoniu.zhou at oss.nxp.com>
---
Changes in v3:
- Call pm_runtime_put() after dw_mipi_csi2rx_stop()
- Balance PM runtime get/put for asymmetric stream enable/disable operations

Changes in v2:
- Simplify error handling by keeping goto labels instead of early returns
---
 drivers/media/platform/synopsys/dw-mipi-csi2rx.c | 35 ++++++++++++++++--------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/drivers/media/platform/synopsys/dw-mipi-csi2rx.c b/drivers/media/platform/synopsys/dw-mipi-csi2rx.c
index f45466ede2bb..92178a3dec5d 100644
--- a/drivers/media/platform/synopsys/dw-mipi-csi2rx.c
+++ b/drivers/media/platform/synopsys/dw-mipi-csi2rx.c
@@ -113,6 +113,7 @@ struct dw_mipi_csi2rx_device {
 
 	enum v4l2_mbus_type bus_type;
 	u32 lanes_num;
+	u64 enabled_streams;
 
 	const struct dw_mipi_csi2rx_drvdata *drvdata;
 };
@@ -539,26 +540,33 @@ static int dw_mipi_csi2rx_enable_streams(struct v4l2_subdev *sd,
 					       DW_MIPI_CSI2RX_PAD_SRC,
 					       &streams_mask);
 
-	ret = pm_runtime_resume_and_get(dev);
-	if (ret)
-		goto err;
+	if (!csi2->enabled_streams) {
+		ret = pm_runtime_resume_and_get(dev);
+		if (ret)
+			goto err;
 
-	ret = dw_mipi_csi2rx_start(csi2);
-	if (ret) {
-		dev_err(dev, "failed to enable CSI hardware\n");
-		goto err_pm_runtime_put;
+		ret = dw_mipi_csi2rx_start(csi2);
+		if (ret) {
+			dev_err(dev, "failed to enable CSI hardware\n");
+			goto err_pm_runtime_put;
+		}
 	}
 
 	ret = v4l2_subdev_enable_streams(remote_sd, remote_pad->index, mask);
 	if (ret)
 		goto err_csi_stop;
 
+	csi2->enabled_streams |= streams_mask;
+
 	return 0;
 
 err_csi_stop:
-	dw_mipi_csi2rx_stop(csi2);
+	/* Stop CSI hardware if no streams are enabled */
+	if (!csi2->enabled_streams)
+		dw_mipi_csi2rx_stop(csi2);
 err_pm_runtime_put:
-	pm_runtime_put(dev);
+	if (!csi2->enabled_streams)
+		pm_runtime_put(dev);
 err:
 	return ret;
 }
@@ -583,10 +591,15 @@ static int dw_mipi_csi2rx_disable_streams(struct v4l2_subdev *sd,
 					       &streams_mask);
 
 	ret = v4l2_subdev_disable_streams(remote_sd, remote_pad->index, mask);
+	if (ret)
+		dev_err(dev, "failed to disable streams on remote subdev: %d\n", ret);
 
-	dw_mipi_csi2rx_stop(csi2);
+	csi2->enabled_streams &= ~streams_mask;
 
-	pm_runtime_put(dev);
+	if (!csi2->enabled_streams) {
+		dw_mipi_csi2rx_stop(csi2);
+		pm_runtime_put(dev);
+	}
 
 	return ret;
 }

-- 
2.34.1