[PATCH v2] media: mipi-csis: Emit V4L2_EVENT_FRAME_SYNC events

[PATCH v2] media: mipi-csis: Emit V4L2_EVENT_FRAME_SYNC events

[Stefan Klug]

The Samsung CSIS MIPI receiver provides a start-of-frame interrupt and
a framecount register. As the CSI receiver is the hardware unit that lies
closest to the sensor, the frame counter is the best we can get on these
devices. In case of the ISI available on the i.MX8 M Plus it is also the
only native start-of-frame signal available.
This patch exposes the sof interrupt and the framecount as
V4L2_EVENT_FRAME_SYNC event on the subdevice.

It was tested on a Debix-Som-A with a 6.8-rc4 kernel.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
---
Changes v1 -> v2:
 - fixed formatting issues from review
 - moved frame variable declaration to top of subscribe_event()

Thanks all for the review!

 drivers/media/platform/nxp/imx-mipi-csis.c | 34 +++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/nxp/imx-mipi-csis.c b/drivers/media/platform/nxp/imx-mipi-csis.c
index db8ff5f5c4d3..664be27c4224 100644
--- a/drivers/media/platform/nxp/imx-mipi-csis.c
+++ b/drivers/media/platform/nxp/imx-mipi-csis.c
@@ -30,6 +30,7 @@
 
 #include <media/v4l2-common.h>
 #include <media/v4l2-device.h>
+#include <media/v4l2-event.h>
 #include <media/v4l2-fwnode.h>
 #include <media/v4l2-mc.h>
 #include <media/v4l2-subdev.h>
@@ -742,6 +743,18 @@ static void mipi_csis_stop_stream(struct mipi_csis_device *csis)
 	mipi_csis_system_enable(csis, false);
 }
 
+static void mipi_csis_queue_event_sof(struct mipi_csis_device *csis)
+{
+	u32 frame;
+	struct v4l2_event event = {
+		.type = V4L2_EVENT_FRAME_SYNC,
+	};
+
+	frame = mipi_csis_read(csis, MIPI_CSIS_FRAME_COUNTER_CH(0));
+	event.u.frame_sync.frame_sequence = frame;
+	v4l2_event_queue(csis->sd.devnode, &event);
+}
+
 static irqreturn_t mipi_csis_irq_handler(int irq, void *dev_id)
 {
 	struct mipi_csis_device *csis = dev_id;
@@ -765,6 +778,10 @@ static irqreturn_t mipi_csis_irq_handler(int irq, void *dev_id)
 				event->counter++;
 		}
 	}
+
+	if (status & MIPI_CSIS_INT_SRC_FRAME_START)
+		mipi_csis_queue_event_sof(csis);
+
 	spin_unlock_irqrestore(&csis->slock, flags);
 
 	mipi_csis_write(csis, MIPI_CSIS_INT_SRC, status);
@@ -1154,8 +1171,23 @@ static int mipi_csis_log_status(struct v4l2_subdev *sd)
 	return 0;
 }
 
+static int mipi_csis_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
+				     struct v4l2_event_subscription *sub)
+{
+	if (sub->type != V4L2_EVENT_FRAME_SYNC)
+		return -EINVAL;
+
+	/* V4L2_EVENT_FRAME_SYNC doesn't require an id, so zero should be set */
+	if (sub->id != 0)
+		return -EINVAL;
+
+	return v4l2_event_subscribe(fh, sub, 0, NULL);
+}
+
 static const struct v4l2_subdev_core_ops mipi_csis_core_ops = {
 	.log_status	= mipi_csis_log_status,
+	.subscribe_event =  mipi_csis_subscribe_event,
+	.unsubscribe_event = v4l2_event_subdev_unsubscribe,
 };
 
 static const struct v4l2_subdev_video_ops mipi_csis_video_ops = {
@@ -1358,7 +1390,7 @@ static int mipi_csis_subdev_init(struct mipi_csis_device *csis)
 	snprintf(sd->name, sizeof(sd->name), "csis-%s",
 		 dev_name(csis->dev));
 
-	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS;
 	sd->ctrl_handler = NULL;
 
 	sd->entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
-- 
2.40.1


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Re: [PATCH v2] media: mipi-csis: Emit V4L2_EVENT_FRAME_SYNC events

[Laurent Pinchart]

Hi Stefan,

Thank you for the patch.

On Thu, Mar 14, 2024 at 10:36:50AM +0100, Stefan Klug wrote:
> The Samsung CSIS MIPI receiver provides a start-of-frame interrupt and
> a framecount register. As the CSI receiver is the hardware unit that lies
> closest to the sensor, the frame counter is the best we can get on these
> devices. In case of the ISI available on the i.MX8 M Plus it is also the
> only native start-of-frame signal available.

You still have either an extra line break or a missing blank line :-)

> This patch exposes the sof interrupt and the framecount as
> V4L2_EVENT_FRAME_SYNC event on the subdevice.
> 
> It was tested on a Debix-Som-A with a 6.8-rc4 kernel.
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
> Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
> ---
> Changes v1 -> v2:
>  - fixed formatting issues from review
>  - moved frame variable declaration to top of subscribe_event()
> 
> Thanks all for the review!
> 
>  drivers/media/platform/nxp/imx-mipi-csis.c | 34 +++++++++++++++++++++-
>  1 file changed, 33 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/nxp/imx-mipi-csis.c b/drivers/media/platform/nxp/imx-mipi-csis.c
> index db8ff5f5c4d3..664be27c4224 100644
> --- a/drivers/media/platform/nxp/imx-mipi-csis.c
> +++ b/drivers/media/platform/nxp/imx-mipi-csis.c
> @@ -30,6 +30,7 @@
>  
>  #include <media/v4l2-common.h>
>  #include <media/v4l2-device.h>
> +#include <media/v4l2-event.h>
>  #include <media/v4l2-fwnode.h>
>  #include <media/v4l2-mc.h>
>  #include <media/v4l2-subdev.h>
> @@ -742,6 +743,18 @@ static void mipi_csis_stop_stream(struct mipi_csis_device *csis)
>  	mipi_csis_system_enable(csis, false);
>  }
>  
> +static void mipi_csis_queue_event_sof(struct mipi_csis_device *csis)
> +{
> +	u32 frame;
> +	struct v4l2_event event = {
> +		.type = V4L2_EVENT_FRAME_SYNC,
> +	};

Nitpicking, we usually sort declarations by decreasing length. No need
for a v3.

> +
> +	frame = mipi_csis_read(csis, MIPI_CSIS_FRAME_COUNTER_CH(0));
> +	event.u.frame_sync.frame_sequence = frame;
> +	v4l2_event_queue(csis->sd.devnode, &event);
> +}
> +
>  static irqreturn_t mipi_csis_irq_handler(int irq, void *dev_id)
>  {
>  	struct mipi_csis_device *csis = dev_id;
> @@ -765,6 +778,10 @@ static irqreturn_t mipi_csis_irq_handler(int irq, void *dev_id)
>  				event->counter++;
>  		}
>  	}
> +
> +	if (status & MIPI_CSIS_INT_SRC_FRAME_START)
> +		mipi_csis_queue_event_sof(csis);
> +
>  	spin_unlock_irqrestore(&csis->slock, flags);
>  
>  	mipi_csis_write(csis, MIPI_CSIS_INT_SRC, status);
> @@ -1154,8 +1171,23 @@ static int mipi_csis_log_status(struct v4l2_subdev *sd)
>  	return 0;
>  }
>  
> +static int mipi_csis_subscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
> +				     struct v4l2_event_subscription *sub)
> +{
> +	if (sub->type != V4L2_EVENT_FRAME_SYNC)
> +		return -EINVAL;
> +
> +	/* V4L2_EVENT_FRAME_SYNC doesn't require an id, so zero should be set */
> +	if (sub->id != 0)
> +		return -EINVAL;
> +
> +	return v4l2_event_subscribe(fh, sub, 0, NULL);
> +}
> +
>  static const struct v4l2_subdev_core_ops mipi_csis_core_ops = {
>  	.log_status	= mipi_csis_log_status,
> +	.subscribe_event =  mipi_csis_subscribe_event,
> +	.unsubscribe_event = v4l2_event_subdev_unsubscribe,
>  };
>  
>  static const struct v4l2_subdev_video_ops mipi_csis_video_ops = {
> @@ -1358,7 +1390,7 @@ static int mipi_csis_subdev_init(struct mipi_csis_device *csis)
>  	snprintf(sd->name, sizeof(sd->name), "csis-%s",
>  		 dev_name(csis->dev));
>  
> -	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS;
>  	sd->ctrl_handler = NULL;
>  
>  	sd->entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;

-- 
Regards,

Laurent Pinchart

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