Re: [PATCH 3/3] drm/mediatek: dpi: add bus format negociation

[CK Hu <ck.hu@mediatek.com>]

Hi, Jitao:

On Tue, 2021-03-30 at 23:53 +0800, Jitao Shi wrote:
> Add the atomic_get_output_bus_fmts, atomic_get_input_bus_fmts to negociate
> the possible output and input formats for the current mode and monitor,
> and use the negotiated formats in a basic atomic_check callback.
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c | 96 ++++++++++++++++++++++++++++++++++++--
>  1 file changed, 91 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index 87bb27649c4c..4e45d1b01b0c 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -81,6 +81,8 @@ struct mtk_dpi {
>  	struct pinctrl *pinctrl;
>  	struct pinctrl_state *pins_gpio;
>  	struct pinctrl_state *pins_dpi;
> +	unsigned int in_bus_format;
> +	unsigned int out_bus_format;

Why do you keep these two value? You does not use them.

>  	bool ddr_edge_sel;
>  	int refcount;
>  };
> @@ -534,6 +536,92 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
>  	return 0;
>  }
>  
> +#define MAX_OUTPUT_SEL_FORMATS	2
> +
> +static u32 *mtk_dpi_bridge_atomic_get_output_bus_fmts(struct drm_bridge *bridge,
> +					struct drm_bridge_state *bridge_state,
> +					struct drm_crtc_state *crtc_state,
> +					struct drm_connector_state *conn_state,
> +					unsigned int *num_output_fmts)
> +{
> +	struct drm_display_mode *mode = &crtc_state->mode;
> +	u32 *output_fmts;
> +	struct mtk_dpi *dpi = bridge_to_dpi(bridge);
> +
> +	*num_output_fmts = 0;
> +
> +	output_fmts = kcalloc(MAX_OUTPUT_SEL_FORMATS, sizeof(*output_fmts),
> +			      GFP_KERNEL);
> +	if (!output_fmts)
> +		return NULL;
> +
> +	/* Default 8bit RGB fallback */
> +	if (dpi->conf->dual_edge) {
> +		output_fmts[0] =  MEDIA_BUS_FMT_RGB888_2X12_LE;
> +		output_fmts[1] =  MEDIA_BUS_FMT_RGB888_2X12_BE;

So mt8183 does not support MEDIA_BUS_FMT_RGB888_1X24?

> +		*num_output_fmts = 2;
> +	} else {
> +		output_fmts[0] =  MEDIA_BUS_FMT_RGB888_1X24;
> +		*num_output_fmts = 1;
> +	}
> +
> +	return output_fmts;
> +}
> +
> +#define MAX_INPUT_SEL_FORMATS	1
> +
> +static u32 *mtk_dpi_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> +					struct drm_bridge_state *bridge_state,
> +					struct drm_crtc_state *crtc_state,
> +					struct drm_connector_state *conn_state,
> +					u32 output_fmt,
> +					unsigned int *num_input_fmts)
> +{
> +	u32 *input_fmts;
> +
> +	*num_input_fmts = 0;
> +
> +	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
> +			     GFP_KERNEL);
> +	if (!input_fmts)
> +		return NULL;
> +
> +	*num_input_fmts = 1;
> +	input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> +
> +	return input_fmts;
> +}
> +
> +static int mtk_dpi_bridge_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 mtk_dpi *dpi = bridge->driver_private;
> +
> +	dpi->out_bus_format = bridge_state->output_bus_cfg.format;
> +
> +	dpi->in_bus_format = bridge_state->input_bus_cfg.format;
> +
> +	dev_dbg(dpi->dev, "input format 0x%04x, output format 0x%04x\n",
> +		bridge_state->input_bus_cfg.format,
> +		bridge_state->output_bus_cfg.format);
> +
> +	if (dpi->out_bus_format == MEDIA_BUS_FMT_RGB888_2X12_LE ||
> +	    dpi->out_bus_format == MEDIA_BUS_FMT_RGB888_2X12_BE) {

I think you could remove this 'if' checking.

Regards,
CK.

> +		dpi->ddr_edge_sel =
> +			(dpi->out_bus_format == MEDIA_BUS_FMT_RGB888_2X12_LE) ?
> +			 true : false;
> +	}
> +
> +	dpi->bit_num = MTK_DPI_OUT_BIT_NUM_8BITS;
> +	dpi->channel_swap = MTK_DPI_OUT_CHANNEL_SWAP_RGB;
> +	dpi->yc_map = MTK_DPI_OUT_YC_MAP_RGB;
> +	dpi->color_format = MTK_DPI_COLOR_FORMAT_RGB;
> +
> +	return 0;
> +}
> +
>  static int mtk_dpi_bridge_attach(struct drm_bridge *bridge,
>  				 enum drm_bridge_attach_flags flags)
>  {
> @@ -572,6 +660,9 @@ static const struct drm_bridge_funcs mtk_dpi_bridge_funcs = {
>  	.mode_set = mtk_dpi_bridge_mode_set,
>  	.disable = mtk_dpi_bridge_disable,
>  	.enable = mtk_dpi_bridge_enable,
> +	.atomic_check = mtk_dpi_bridge_atomic_check,
> +	.atomic_get_output_bus_fmts = mtk_dpi_bridge_atomic_get_output_bus_fmts,
> +	.atomic_get_input_bus_fmts = mtk_dpi_bridge_atomic_get_input_bus_fmts,
>  };
>  
>  static void mtk_dpi_start(struct mtk_ddp_comp *comp)
> @@ -621,11 +712,6 @@ static int mtk_dpi_bind(struct device *dev, struct device *master, void *data)
>  		goto err_cleanup;
>  	}
>  
> -	dpi->bit_num = MTK_DPI_OUT_BIT_NUM_8BITS;
> -	dpi->channel_swap = MTK_DPI_OUT_CHANNEL_SWAP_RGB;
> -	dpi->yc_map = MTK_DPI_OUT_YC_MAP_RGB;
> -	dpi->color_format = MTK_DPI_COLOR_FORMAT_RGB;
> -
>  	return 0;
>  
>  err_cleanup: