Re: [PATCH v9 10/18] drm: bridge: samsung-dsim: Init exynos host for first DSI transfer

[Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>]

Hi Jagan,

On 09.12.2022 16:23, Jagan Teki wrote:
> The existing drm panels and bridges in Exynos required host
> initialization during the first DSI command transfer even though
> the initialization was done before.
>
> This host reinitialization is handled via DSIM_STATE_REINITIALIZED
> flag and triggers from host transfer.
>
> Do this exclusively for Exynos.
>
> Initial logic is derived from Marek Szyprowski changes.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
> ---
> Changes from v9:
> - derived from v8
> - added comments
>
>   drivers/gpu/drm/bridge/samsung-dsim.c | 15 ++++++++++++++-
>   include/drm/bridge/samsung-dsim.h     |  5 +++--
>   2 files changed, 17 insertions(+), 3 deletions(-)

The following chunk is missing compared to v8:

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c 
b/drivers/gpu/drm/bridge/samsung-dsim.c
index 6e9ad955ebd3..6a9403cb92ae 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1315,7 +1315,9 @@ static int samsung_dsim_init(struct samsung_dsim 
*dsi, unsigned int flag)
                 return 0;

         samsung_dsim_reset(dsi);
-       samsung_dsim_enable_irq(dsi);
+
+       if (!(dsi->state & DSIM_STATE_INITIALIZED))
+               samsung_dsim_enable_irq(dsi);

         if (driver_data->reg_values[RESET_TYPE] == DSIM_FUNCRST)
                 samsung_dsim_enable_lane(dsi, BIT(dsi->lanes) - 1);


> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
> index 2e15d753fdd0..ec3ab679afd9 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -1254,6 +1254,19 @@ static int samsung_dsim_init(struct samsung_dsim *dsi, unsigned int flag)
>   {
>   	const struct samsung_dsim_driver_data *driver_data = dsi->driver_data;
>   
> +	/*
> +	 * FIXME:
> +	 * The existing drm panels and bridges in Exynos required host
> +	 * initialization during the first DSI command transfer even though
> +	 * the initialization was done before.
> +	 *
> +	 * This host reinitialization is handled via DSIM_STATE_REINITIALIZED
> +	 * flag and triggers from host transfer. Do this exclusively for Exynos.
> +	 */
> +	if ((dsi->plat_data->hw_type == SAMSUNG_DSIM_TYPE_IMX8MM) &&
> +	    dsi->state & DSIM_STATE_REINITIALIZED)
> +		return 0;
> +
>   	if (dsi->state & flag)
>   		return 0;
>   
> @@ -1467,7 +1480,7 @@ static ssize_t samsung_dsim_host_transfer(struct mipi_dsi_host *host,
>   	if (!(dsi->state & DSIM_STATE_ENABLED))
>   		return -EINVAL;
>   
> -	ret = samsung_dsim_init(dsi, DSIM_STATE_INITIALIZED);
> +	ret = samsung_dsim_init(dsi, DSIM_STATE_REINITIALIZED);
>   	if (ret)
>   		return ret;
>   
> diff --git a/include/drm/bridge/samsung-dsim.h b/include/drm/bridge/samsung-dsim.h
> index b8132bf8e36f..0c5a905f3de7 100644
> --- a/include/drm/bridge/samsung-dsim.h
> +++ b/include/drm/bridge/samsung-dsim.h
> @@ -17,8 +17,9 @@ struct samsung_dsim;
>   
>   #define DSIM_STATE_ENABLED		BIT(0)
>   #define DSIM_STATE_INITIALIZED		BIT(1)
> -#define DSIM_STATE_CMD_LPM		BIT(2)
> -#define DSIM_STATE_VIDOUT_AVAILABLE	BIT(3)
> +#define DSIM_STATE_REINITIALIZED	BIT(2)
> +#define DSIM_STATE_CMD_LPM		BIT(3)
> +#define DSIM_STATE_VIDOUT_AVAILABLE	BIT(4)
>   
>   enum samsung_dsim_type {
>   	SAMSUNG_DSIM_TYPE_EXYNOS3250,

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