Re: [PATCH v5 06/11] drm: bridge: samsung-dsim: Add atomic_check

[Marek Szyprowski <m.szyprowski@samsung.com>]

Hi Jagan,

On 16.09.2022 20:17, Jagan Teki wrote:
> Look like an explicit fixing up of mode_flags is required for DSIM IP
> present in i.MX8M Mini/Nano SoCs.
>
> At least the LCDIF + DSIM needs active low sync polarities in order
> to correlate the correct sync flags of the surrounding components in
> the chain to make sure the whole pipeline can work properly.
>
> On the other hand the i.MX 8M Mini Applications Processor Reference Manual,
> Rev. 3, 11/2020 says.
> "13.6.3.5.2 RGB interface
>   Vsync, Hsync, and VDEN are active high signals."
>
> No clear evidence about whether it can be documentation issues or
> something, so added a comment FIXME for this and updated the active low
> sync polarities using SAMSUNG_DSIM_TYPE_IMX8MM hw_type.
>
> v5:
> * rebase based new bridge changes [mszyprow]
> * remove DSIM_QUIRK_FIXUP_SYNC_POL
> * add hw_type check for sync polarities change.
>
> v4:
> * none
>
> v3:
> * add DSIM_QUIRK_FIXUP_SYNC_POL to handle mode_flasg fixup
>
> v2:
> * none
>
> v1:
> * fix mode flags in atomic_check instead of mode_fixup
>
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> ---
>   drivers/gpu/drm/bridge/samsung-dsim.c | 26 ++++++++++++++++++++++++++
>   include/drm/bridge/samsung-dsim.h     |  1 +
>   2 files changed, 27 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
> index 6d524338d4ff..8abf89326424 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -1315,6 +1315,31 @@ static void samsung_dsim_atomic_post_disable(struct drm_bridge *bridge,
>   	pm_runtime_put_sync(dsi->dev);
>   }
>   
> +static int samsung_dsim_atomic_check(struct drm_bridge *bridge,
> +				     struct drm_bridge_state *bridge_state,
> +				     struct drm_crtc_state *crtc_state,
> +				     struct drm_connector_state *conn_state)
> +{
> +	struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> +	struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
> +
> +	if (dsi->plat_data->hw_type & SAMSUNG_DSIM_TYPE_IMX8MM) {

Again the above should be 'if (dsi->plat_data->hw_type == 
SAMSUNG_DSIM_TYPE_IMX8MM)', hw_type is not a bitmask.


> +		/**
> +		 * FIXME:
> +		 * At least LCDIF + DSIM needs active low sync,
> +		 * but i.MX 8M Mini Applications Processor Reference Manual,
> +		 * Rev. 3, 11/2020 says
> +		 *
> +		 * 13.6.3.5.2 RGB interface
> +		 * Vsync, Hsync, and VDEN are active high signals.
> +		 */
> +		adjusted_mode->flags |= (DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
> +		adjusted_mode->flags &= ~(DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
> +	}
> +
> +	return 0;
> +}
> +
>   static void samsung_dsim_mode_set(struct drm_bridge *bridge,
>   				  const struct drm_display_mode *mode,
>   				  const struct drm_display_mode *adjusted_mode)
> @@ -1337,6 +1362,7 @@ static const struct drm_bridge_funcs samsung_dsim_bridge_funcs = {
>   	.atomic_duplicate_state		= drm_atomic_helper_bridge_duplicate_state,
>   	.atomic_destroy_state		= drm_atomic_helper_bridge_destroy_state,
>   	.atomic_reset			= drm_atomic_helper_bridge_reset,
> +	.atomic_check			= samsung_dsim_atomic_check,
>   	.atomic_pre_enable		= samsung_dsim_atomic_pre_enable,
>   	.atomic_enable			= samsung_dsim_atomic_enable,
>   	.atomic_disable			= samsung_dsim_atomic_disable,
> diff --git a/include/drm/bridge/samsung-dsim.h b/include/drm/bridge/samsung-dsim.h
> index 57b27d75369e..0c5a905f3de7 100644
> --- a/include/drm/bridge/samsung-dsim.h
> +++ b/include/drm/bridge/samsung-dsim.h
> @@ -27,6 +27,7 @@ enum samsung_dsim_type {
>   	SAMSUNG_DSIM_TYPE_EXYNOS5410,
>   	SAMSUNG_DSIM_TYPE_EXYNOS5422,
>   	SAMSUNG_DSIM_TYPE_EXYNOS5433,
> +	SAMSUNG_DSIM_TYPE_IMX8MM,
>   	SAMSUNG_DSIM_TYPE_COUNT,
>   };
>   

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland


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