linux-kernel - Re: [PATCH v7 5/8] drm/mediatek: dpi: Add dpintf support

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Date:   Wed, 19 Jan 2022 17:15:31 +0800
From:   CK Hu <ck.hu@...iatek.com>
To:     Guillaume Ranquet <granquet@...libre.com>,
        Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        "David Airlie" <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        "Matthias Brugger" <matthias.bgg@...il.com>
CC:     <linux-kernel@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
        "Markus Schneider-Pargmann" <msp@...libre.com>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
Subject: Re: [PATCH v7 5/8] drm/mediatek: dpi: Add dpintf support

Hi, Guillaume:

On Fri, 2021-12-17 at 16:08 +0100, Guillaume Ranquet wrote:
> From: Markus Schneider-Pargmann <msp@...libre.com>
> 
> dpintf is the displayport interface hardware unit. This unit is
> similar
> to dpi and can reuse most of the code.
> 
> This patch adds support for mt8195-dpintf to this dpi driver. Main
> differences are:
>  - Some features/functional components are not available for dpintf
>    which are now excluded from code execution once is_dpintf is set
>  - dpintf can and needs to choose between different clockdividers
> based
>    on the clockspeed. This is done by choosing a different clock
> parent.
>  - There are two additional clocks that need to be managed. These are
>    only set for dpintf and will be set to NULL if not supplied. The
>    clk_* calls handle these as normal clocks then.
>  - Some register contents differ slightly between the two components.
> To
>    work around this I added register bits/masks with a DPINTF_ prefix
>    and use them where different.
> 
> Based on a separate driver for dpintf created by
> Jason-JH.Lin <jason-jh.lin@...iatek.com>.
> 
> Signed-off-by: Markus Schneider-Pargmann <msp@...libre.com>
> Signed-off-by: Guillaume Ranquet <granquet@...libre.com>
> Reviewed-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@...labora.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c          | 304 ++++++++++++++++
> ----
>  drivers/gpu/drm/mediatek/mtk_dpi_regs.h     |  38 +++
>  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c |   4 +
>  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h |   1 +
>  drivers/gpu/drm/mediatek/mtk_drm_drv.c      |   5 +-
>  include/linux/soc/mediatek/mtk-mmsys.h      |   2 +
>  6 files changed, 299 insertions(+), 55 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c
> b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index 4554e2de14309..fbc43ea4049b9 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -63,6 +63,14 @@ enum mtk_dpi_out_color_format {
>  	MTK_DPI_COLOR_FORMAT_YCBCR_422_FULL
>  };
>  
> +enum TVDPLL_CLK {
> +	TVDPLL_PLL = 0,
> +	TVDPLL_D2 = 2,
> +	TVDPLL_D4 = 4,
> +	TVDPLL_D8 = 8,
> +	TVDPLL_D16 = 16,
> +};
> +
>  struct mtk_dpi {
>  	struct drm_encoder encoder;
>  	struct drm_bridge bridge;
> @@ -71,8 +79,10 @@ struct mtk_dpi {
>  	void __iomem *regs;
>  	struct device *dev;
>  	struct clk *engine_clk;
> +	struct clk *dpi_ck_cg;
>  	struct clk *pixel_clk;
>  	struct clk *tvd_clk;
> +	struct clk *pclk_src[5];
>  	int irq;
>  	struct drm_display_mode mode;
>  	const struct mtk_dpi_conf *conf;
> @@ -125,6 +135,18 @@ struct mtk_dpi_conf {
>  	bool edge_sel_en;
>  	const u32 *output_fmts;
>  	u32 num_output_fmts;
> +	bool is_ck_de_pol;

Seperate is_ck_de_pol to an independent patch.

> +	bool is_dpintf;

Ditto for is_dpintf. And I would like change the name to what this
actually do.

> +	bool csc_support;

Ditto for csc_support.

> +	bool swap_input_support;

Ditto for swap_input_support.

> +	// Mask used for HWIDTH, HPORCH, VSYNC_WIDTH and VSYNC_PORCH 

/* ... */

> (no shift)
> +	u32 dimension_mask;

Ditto for dimension_mask.

> +	// Mask used for HSIZE and VSIZE (no shift)
> +	u32 hvsize_mask;

Ditto for hvsize_mask.

> +	u32 channel_swap_shift;

Ditto for channel_swap_shift.

> +	u32 yuv422_en_bit;

Ditto for yuv422_en_bit.

> +	u32 csc_enable_bit;

Ditto for csc_enable_bit.

> +	const struct mtk_dpi_yc_limit *limit;

Ditto for limit.

>  };
>  
>  
> +
> +static const struct mtk_dpi_conf mt8195_dpintf_conf = {
> +	.cal_factor = mt8195_dpintf_calculate_factor,
> +	.output_fmts = mt8195_output_fmts,
> +	.num_output_fmts = ARRAY_SIZE(mt8195_output_fmts),
> +	.is_dpintf = true,
> +	.csc_support = true,

For every SoC, csc_support is true. Why do we need csc_support?

Regards,
CK

> +	.dimension_mask = DPINTF_HPW_MASK,
> +	.hvsize_mask = DPINTF_HSIZE_MASK,
> +	.channel_swap_shift = DPINTF_CH_SWAP,
> +	.yuv422_en_bit = DPINTF_YUV422_EN,
> +	.csc_enable_bit = DPINTF_CSC_ENABLE,
> +	.limit = &mtk_dpintf_limit,
>  };
>  
>