On Tue, Feb 18, 2020 at 07:50:33PM +0200, Andrey Lebedev wrote:
> On Mon, Feb 17, 2020 at 06:51:35PM +0100, Maxime Ripard wrote:
> > > diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h b/drivers/gpu/drm/sun4i/sun4i_tcon.h
> > > index cfbf4e6c1679..bc87d28ee341 100644
> > > --- a/drivers/gpu/drm/sun4i/sun4i_tcon.h
> > > +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.h
> > > @@ -235,6 +235,8 @@ struct sun4i_tcon_quirks {
> > >  	bool	needs_de_be_mux; /* sun6i needs mux to select backend */
> > >  	bool    needs_edp_reset; /* a80 edp reset needed for tcon0 access */
> > >  	bool	supports_lvds;   /* Does the TCON support an LVDS output? */
> > > +	/* "compatible" string of TCON that exclusively supports LVDS */
> > > +	const char *lvds_compatible_tcon;
> >
> > However this is far more complicated than needed, you can simply add a
> > new quirks structure associated to the tcon0 compatible in
> > sun4i_tcon_of_table, and that will do
>
> Aha! Does this look good to you?
>
> From 4ad2978e404c63d4cca1b7890bc5bdd4d1e8965d Mon Sep 17 00:00:00 2001
> From: Andrey Lebedev <andrey@lebedev.lt>
> Date: Tue, 18 Feb 2020 19:47:33 +0200
> Subject: [PATCH] Mark tcon0 to be the only tcon capable of LVDS on sun7i-a20
>
> This allows to avoid warnings about reset line not provided for tcon1.
>
> Signed-off-by: Andrey Lebedev <andrey@lebedev.lt>
> ---
>  arch/arm/boot/dts/sun7i-a20.dtsi   |  6 ++++--
>  drivers/gpu/drm/sun4i/sun4i_tcon.c | 14 ++++++++++++--
>  2 files changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/boot/dts/sun7i-a20.dtsi b/arch/arm/boot/dts/sun7i-a20.dtsi
> index dc4f3f249aee..d50263c1ca9a 100644
> --- a/arch/arm/boot/dts/sun7i-a20.dtsi
> +++ b/arch/arm/boot/dts/sun7i-a20.dtsi
> @@ -405,7 +405,8 @@
>  		};
>
>  		tcon0: lcd-controller@1c0c000 {
> -			compatible = "allwinner,sun7i-a20-tcon";
> +			compatible = "allwinner,sun7i-a20-tcon0",
> +				     "allwinner,sun7i-a20-tcon";
>  			reg = <0x01c0c000 0x1000>;
>  			interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_HIGH>;
>  			resets = <&ccu RST_TCON0>, <&ccu RST_LVDS>;
> @@ -460,7 +461,8 @@
>  		};
>
>  		tcon1: lcd-controller@1c0d000 {
> -			compatible = "allwinner,sun7i-a20-tcon";
> +			compatible = "allwinner,sun7i-a20-tcon1",
> +				     "allwinner,sun7i-a20-tcon";
>  			reg = <0x01c0d000 0x1000>;
>  			interrupts = <GIC_SPI 45 IRQ_TYPE_LEVEL_HIGH>;
>  			resets = <&ccu RST_TCON1>;

This needs to be in a separate patch

> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> index 800a9bd86112..d9605d331010 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> @@ -1479,7 +1479,7 @@ static const struct sun4i_tcon_quirks sun6i_a31s_quirks = {
>  	.dclk_min_div		= 1,
>  };
>
> -static const struct sun4i_tcon_quirks sun7i_a20_quirks = {
> +static const struct sun4i_tcon_quirks sun7i_a20_tcon0_quirks = {
>  	.supports_lvds		= true,
>  	.has_channel_0		= true,
>  	.has_channel_1		= true,
> @@ -1489,6 +1489,15 @@ static const struct sun4i_tcon_quirks sun7i_a20_quirks = {
>  	.setup_lvds_phy		= sun4i_tcon_setup_lvds_phy,
>  };
>
> +static const struct sun4i_tcon_quirks sun7i_a20_tcon1_quirks = {
> +	.supports_lvds		= false,
> +	.has_channel_0		= true,
> +	.has_channel_1		= true,
> +	.dclk_min_div		= 4,
> +	/* Same display pipeline structure as A10 */
> +	.set_mux		= sun4i_a10_tcon_set_mux,
> +};
> +
>  static const struct sun4i_tcon_quirks sun8i_a33_quirks = {
>  	.has_channel_0		= true,
>  	.has_lvds_alt		= true,
> @@ -1534,7 +1543,8 @@ const struct of_device_id sun4i_tcon_of_table[] = {
>  	{ .compatible = "allwinner,sun5i-a13-tcon", .data = &sun5i_a13_quirks },
>  	{ .compatible = "allwinner,sun6i-a31-tcon", .data = &sun6i_a31_quirks },
>  	{ .compatible = "allwinner,sun6i-a31s-tcon", .data = &sun6i_a31s_quirks },
> -	{ .compatible = "allwinner,sun7i-a20-tcon", .data = &sun7i_a20_quirks },
> +	{ .compatible = "allwinner,sun7i-a20-tcon0", .data = &sun7i_a20_tcon0_quirks },
> +	{ .compatible = "allwinner,sun7i-a20-tcon1", .data = &sun7i_a20_tcon1_quirks },
>  	{ .compatible = "allwinner,sun8i-a23-tcon", .data = &sun8i_a33_quirks },
>  	{ .compatible = "allwinner,sun8i-a33-tcon", .data = &sun8i_a33_quirks },
>  	{ .compatible = "allwinner,sun8i-a83t-tcon-lcd", .data = &sun8i_a83t_lcd_quirks },

And we need to support older DT as well, so you shouldn't remove the
older TCON compatible and its structure. Make sure to document the new
compatibles too.

Maxime