[v2,0/2] media: Add line end IRQ to imx-mipi-csis driver

Many boards, such as the NXP i.MX 8M Plus, feature multiple interrupt
registers. This series refactors interrupt status register debug handling to make
it more intuitive to add other registers such as LINE_END, which has an
entire register containing only one interrupt. Previously, the
mipi_csi_events[] list contained a debug enable field, and this replaces
that with a status_index, which indicates which status register contains
the mask for the interrupt.

The second patch adds the user line interrupt, which is useful for
debugging, as it allows a user to trigger an interrupt after the MIPI
CSI receiver has counted a configurable number of lines. This can make
it possible to discern the true resolution of the image stream reaching
the CSI receiver. It adds an entry to debugfs which lets users choose
how many lines are needed to trigger the interrupt, and can be disabled
both within and outside streaming by setting the value to 0.

---

Changes since v1:
- Moved from magic number to enum in status_index
- Clear INT_MSK_1 in enable_interrupts() when on == false
- use local variable in set_params() as in the interrupt handler
- move interrupt handling code outside of spinlock

Isaac Scott (2):
  media: platform: Refactor interrupt status registers
  media: platform: Add user line interrupt to imx-mipi-csis driver

 drivers/media/platform/nxp/imx-mipi-csis.c | 107 ++++++++++++++-------
 1 file changed, 74 insertions(+), 33 deletions(-)

Hi Isaac,

Thank you for the patch.

The subject line should start with "media: imx-mipi-csis: ".

On Fri, Jun 06, 2025 at 04:44:13PM +0100, Isaac Scott wrote:
> The NXP i.MX 8 MP CSI-2 receiver features multiple interrupt and debug
> status sources which span multiple registers. The driver currently
> supports two interrupt source registers, and attributes the
> mipi_csis_event event entries to those registers through a boolean debug
> field that indicate if the event relates to the main interrupt status
> (false) or debug interrupt status (true) register. To make it easier to
> add new event fields, replace the debug bool with a 'status index'
> integer than indicates the index of the corresponding status register.
> 
> Signed-off-by: Isaac Scott <isaac.scott@ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> ---
> 
> Changes since v1:
> - Switched from magic numbers to enum.
> ---
>  drivers/media/platform/nxp/imx-mipi-csis.c | 69 +++++++++++-----------
>  1 file changed, 36 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/media/platform/nxp/imx-mipi-csis.c b/drivers/media/platform/nxp/imx-mipi-csis.c
> index d060eadebc7a..394987d72c64 100644
> --- a/drivers/media/platform/nxp/imx-mipi-csis.c
> +++ b/drivers/media/platform/nxp/imx-mipi-csis.c
> @@ -248,8 +248,13 @@
>  #define MIPI_CSI2_DATA_TYPE_RAW14		0x2d
>  #define MIPI_CSI2_DATA_TYPE_USER(x)		(0x30 + (x))
>  
> +enum mipi_csis_event_type {
> +	MAIN = 0,
> +	DEBUG = 1,

Those names are too generic and prone to namespace clashes.
MIPI_CSIS_EVENT_TYPE_MAIN and MIPI_CSIS_EVENT_TYPE_DEBUG would be
better.

No need to resubmit for this, I'll update the code when applying.

> +};
> +
>  struct mipi_csis_event {
> -	bool debug;
> +	enum mipi_csis_event_type status_index;
>  	u32 mask;
>  	const char * const name;
>  	unsigned int counter;
> @@ -257,30 +262,30 @@ struct mipi_csis_event {
>  
>  static const struct mipi_csis_event mipi_csis_events[] = {
>  	/* Errors */
> -	{ false, MIPI_CSIS_INT_SRC_ERR_SOT_HS,		"SOT Error" },
> -	{ false, MIPI_CSIS_INT_SRC_ERR_LOST_FS,		"Lost Frame Start Error" },
> -	{ false, MIPI_CSIS_INT_SRC_ERR_LOST_FE,		"Lost Frame End Error" },
> -	{ false, MIPI_CSIS_INT_SRC_ERR_OVER,		"FIFO Overflow Error" },
> -	{ false, MIPI_CSIS_INT_SRC_ERR_WRONG_CFG,	"Wrong Configuration Error" },
> -	{ false, MIPI_CSIS_INT_SRC_ERR_ECC,		"ECC Error" },
> -	{ false, MIPI_CSIS_INT_SRC_ERR_CRC,		"CRC Error" },
> -	{ false, MIPI_CSIS_INT_SRC_ERR_UNKNOWN,		"Unknown Error" },
> -	{ true, MIPI_CSIS_DBG_INTR_SRC_DT_NOT_SUPPORT,	"Data Type Not Supported" },
> -	{ true, MIPI_CSIS_DBG_INTR_SRC_DT_IGNORE,	"Data Type Ignored" },
> -	{ true, MIPI_CSIS_DBG_INTR_SRC_ERR_FRAME_SIZE,	"Frame Size Error" },
> -	{ true, MIPI_CSIS_DBG_INTR_SRC_TRUNCATED_FRAME,	"Truncated Frame" },
> -	{ true, MIPI_CSIS_DBG_INTR_SRC_EARLY_FE,	"Early Frame End" },
> -	{ true, MIPI_CSIS_DBG_INTR_SRC_EARLY_FS,	"Early Frame Start" },
> +	{ MAIN, MIPI_CSIS_INT_SRC_ERR_SOT_HS,			"SOT Error"},
> +	{ MAIN, MIPI_CSIS_INT_SRC_ERR_LOST_FS,			"Lost Frame Start Error"},
> +	{ MAIN, MIPI_CSIS_INT_SRC_ERR_LOST_FE,			"Lost Frame End Error"},
> +	{ MAIN, MIPI_CSIS_INT_SRC_ERR_OVER,			"FIFO Overflow Error"},
> +	{ MAIN, MIPI_CSIS_INT_SRC_ERR_WRONG_CFG,		"Wrong Configuration Error"},
> +	{ MAIN, MIPI_CSIS_INT_SRC_ERR_ECC,			"ECC Error"},
> +	{ MAIN, MIPI_CSIS_INT_SRC_ERR_CRC,			"CRC Error"},
> +	{ MAIN, MIPI_CSIS_INT_SRC_ERR_UNKNOWN,			"Unknown Error"},
> +	{ DEBUG, MIPI_CSIS_DBG_INTR_SRC_DT_NOT_SUPPORT,		"Data Type Not Supported"},
> +	{ DEBUG, MIPI_CSIS_DBG_INTR_SRC_DT_IGNORE,		"Data Type Ignored"},
> +	{ DEBUG, MIPI_CSIS_DBG_INTR_SRC_ERR_FRAME_SIZE,		"Frame Size Error"},
> +	{ DEBUG, MIPI_CSIS_DBG_INTR_SRC_TRUNCATED_FRAME,	"Truncated Frame"},
> +	{ DEBUG, MIPI_CSIS_DBG_INTR_SRC_EARLY_FE,		"Early Frame End"},
> +	{ DEBUG, MIPI_CSIS_DBG_INTR_SRC_EARLY_FS,		"Early Frame Start"},
>  	/* Non-image data receive events */
> -	{ false, MIPI_CSIS_INT_SRC_EVEN_BEFORE,		"Non-image data before even frame" },
> -	{ false, MIPI_CSIS_INT_SRC_EVEN_AFTER,		"Non-image data after even frame" },
> -	{ false, MIPI_CSIS_INT_SRC_ODD_BEFORE,		"Non-image data before odd frame" },
> -	{ false, MIPI_CSIS_INT_SRC_ODD_AFTER,		"Non-image data after odd frame" },
> +	{ MAIN, MIPI_CSIS_INT_SRC_EVEN_BEFORE,			"Non-image data before even frame"},
> +	{ MAIN, MIPI_CSIS_INT_SRC_EVEN_AFTER,			"Non-image data after even frame"},
> +	{ MAIN, MIPI_CSIS_INT_SRC_ODD_BEFORE,			"Non-image data before odd frame"},
> +	{ MAIN, MIPI_CSIS_INT_SRC_ODD_AFTER,			"Non-image data after odd frame"},
>  	/* Frame start/end */
> -	{ false, MIPI_CSIS_INT_SRC_FRAME_START,		"Frame Start" },
> -	{ false, MIPI_CSIS_INT_SRC_FRAME_END,		"Frame End" },
> -	{ true, MIPI_CSIS_DBG_INTR_SRC_CAM_VSYNC_FALL,	"VSYNC Falling Edge" },
> -	{ true, MIPI_CSIS_DBG_INTR_SRC_CAM_VSYNC_RISE,	"VSYNC Rising Edge" },
> +	{ MAIN, MIPI_CSIS_INT_SRC_FRAME_START,			"Frame Start"},
> +	{ MAIN, MIPI_CSIS_INT_SRC_FRAME_END,			"Frame End"},
> +	{ DEBUG, MIPI_CSIS_DBG_INTR_SRC_CAM_VSYNC_FALL,		"VSYNC Falling Edge"},
> +	{ DEBUG, MIPI_CSIS_DBG_INTR_SRC_CAM_VSYNC_RISE,		"VSYNC Rising Edge"},
>  };
>  
>  #define MIPI_CSIS_NUM_EVENTS ARRAY_SIZE(mipi_csis_events)
> @@ -765,32 +770,30 @@ static irqreturn_t mipi_csis_irq_handler(int irq, void *dev_id)
>  	struct mipi_csis_device *csis = dev_id;
>  	unsigned long flags;
>  	unsigned int i;
> -	u32 status;
> -	u32 dbg_status;
> +	u32 status[2];
>  
> -	status = mipi_csis_read(csis, MIPI_CSIS_INT_SRC);
> -	dbg_status = mipi_csis_read(csis, MIPI_CSIS_DBG_INTR_SRC);
> +	status[MAIN] = mipi_csis_read(csis, MIPI_CSIS_INT_SRC);
> +	status[DEBUG] = mipi_csis_read(csis, MIPI_CSIS_DBG_INTR_SRC);
>  
>  	spin_lock_irqsave(&csis->slock, flags);
>  
>  	/* Update the event/error counters */
> -	if ((status & MIPI_CSIS_INT_SRC_ERRORS) || csis->debug.enable) {
> +	if ((status[MAIN] & MIPI_CSIS_INT_SRC_ERRORS) || csis->debug.enable) {
>  		for (i = 0; i < MIPI_CSIS_NUM_EVENTS; i++) {
>  			struct mipi_csis_event *event = &csis->events[i];
>  
> -			if ((!event->debug && (status & event->mask)) ||
> -			    (event->debug && (dbg_status & event->mask)))
> +			if (status[event->status_index] & event->mask)
>  				event->counter++;
>  		}
>  	}
>  
> -	if (status & MIPI_CSIS_INT_SRC_FRAME_START)
> +	if (status[MAIN] & 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);
> -	mipi_csis_write(csis, MIPI_CSIS_DBG_INTR_SRC, dbg_status);
> +	mipi_csis_write(csis, MIPI_CSIS_INT_SRC, status[MAIN]);
> +	mipi_csis_write(csis, MIPI_CSIS_DBG_INTR_SRC, status[DEBUG]);
>  
>  	return IRQ_HANDLED;
>  }