[v1,1/1] media: rkisp1: Fix filter mode register configuration

25283 diff mbox series

The rkisp1_flt_config() function performs an initial direct write to
RKISP1_CIF_ISP_FILT_MODE without including the RKISP1_CIF_ISP_FLT_ENA
bit, which clears the filter enable bit in the hardware.

The subsequent read/modify/write sequence then reads back the register
with the enable bit already cleared and cannot restore it, resulting in
the filter being inadvertently disabled.

Remove the redundant direct write. The read/modify/write sequence alone
correctly preserves the existing enable bit state while updating the
DNR mode and filter configuration bits.

Signed-off-by: Rui Wang <rui.wang@ideasonboard.com>
---
 drivers/media/platform/rockchip/rkisp1/rkisp1-params.c | 6 ------
 1 file changed, 6 deletions(-)

Hi Rui,

Thank you for the patch.

Quoting Rui Wang (2025-12-02 02:50:25)
> The rkisp1_flt_config() function performs an initial direct write to
> RKISP1_CIF_ISP_FILT_MODE without including the RKISP1_CIF_ISP_FLT_ENA
> bit, which clears the filter enable bit in the hardware.

That sentence is a bit hard for me to understand. Maybe:

"The rkisp1_flt_config() function overwrites RKISP1_CIF_ISP_FILT_MODE
without preserving the RKISP1_CIF_ISP_FLT_ENA bit thereby unconditionally
disabling the hardware block on reconfiguration.

But as I'm no native speaker you could maybe wait for feedback from a
native speaker.

Functionality wise the change is correct.

Reviewed-by: Stefan Klug <stefan.klug@ideasonboard.com>

Best regards,
Stefan

> 
> The subsequent read/modify/write sequence then reads back the register
> with the enable bit already cleared and cannot restore it, resulting in
> the filter being inadvertently disabled.
> 
> Remove the redundant direct write. The read/modify/write sequence alone
> correctly preserves the existing enable bit state while updating the
> DNR mode and filter configuration bits.
> 
> Signed-off-by: Rui Wang <rui.wang@ideasonboard.com>
> ---
>  drivers/media/platform/rockchip/rkisp1/rkisp1-params.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c
> index c9f88635224c..6442436a5e42 100644
> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c
> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c
> @@ -411,12 +411,6 @@ static void rkisp1_flt_config(struct rkisp1_params *params,
>         rkisp1_write(params->rkisp1, RKISP1_CIF_ISP_FILT_LUM_WEIGHT,
>                      arg->lum_weight);
>  
> -       rkisp1_write(params->rkisp1, RKISP1_CIF_ISP_FILT_MODE,
> -                    (arg->mode ? RKISP1_CIF_ISP_FLT_MODE_DNR : 0) |
> -                    RKISP1_CIF_ISP_FLT_CHROMA_V_MODE(arg->chr_v_mode) |
> -                    RKISP1_CIF_ISP_FLT_CHROMA_H_MODE(arg->chr_h_mode) |
> -                    RKISP1_CIF_ISP_FLT_GREEN_STAGE1(arg->grn_stage1));
> -
>         /* avoid to override the old enable value */
>         filt_mode = rkisp1_read(params->rkisp1, RKISP1_CIF_ISP_FILT_MODE);
>         filt_mode &= RKISP1_CIF_ISP_FLT_ENA;
> -- 
> 2.43.0
>