linux-kernel - Re: [PATCH 3/5] drm/sun4i: Enable LVDS output on sun20i D1s/T113

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Message-ID: <aFut-yuJS2lfWaE8@shepard>
Date: Wed, 25 Jun 2025 10:06:19 +0200
From: Paul Kocialkowski <paulk@...-base.io>
To: Kuba Szczodrzyński <kuba@...zodrzynski.pl>
Cc: Maxime Ripard <mripard@...nel.org>,
	Samuel Holland <samuel@...lland.org>, Chen-Yu Tsai <wens@...e.org>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
	linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org,
	linux-phy@...ts.infradead.org, devicetree@...r.kernel.org,
	dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH 3/5] drm/sun4i: Enable LVDS output on sun20i D1s/T113

Hi,

Some comments below.

On Fri 21 Feb 25, 17:17, Kuba Szczodrzyński wrote:
> The Allwinner D1s/T113 needs to use the combo D-PHY to enable LVDS
> output.
> 
> Enable LVDS support in the TCON and configure it using the PHY.
> 
> Signed-off-by: Kuba Szczodrzyński <kuba@...zodrzynski.pl>
> ---
>  drivers/gpu/drm/sun4i/sun4i_tcon.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> index ccf335a61..58230a552 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
> @@ -171,6 +171,30 @@ static void sun6i_tcon_setup_lvds_phy(struct sun4i_tcon *tcon,
>  			  SUN6I_TCON0_LVDS_ANA0_EN_DRVD(val));
>  }
>  
> +static void sun20i_tcon_setup_lvds_dphy(struct sun4i_tcon *tcon,
> +					const struct drm_encoder *encoder)
> +{
> +	union phy_configure_opts opts = { };
> +
> +	if (!tcon->quirks->has_combo_dphy || !tcon->dphy)
> +		return;
> +
> +	phy_init(tcon->dphy);
> +	phy_set_mode(tcon->dphy, PHY_MODE_LVDS);
> +	phy_configure(tcon->dphy, &opts);
> +	phy_power_on(tcon->dphy);

While the callback doesn't have any return code (and it probably should, feel
free to fix that), the return codes for the phy_ calls should be checked and
the function aborted early in case of error.

> +}
> +
> +static void sun20i_tcon_disable_lvds_dphy(struct sun4i_tcon *tcon,
> +					  const struct drm_encoder *encoder)
> +{
> +	if (!tcon->quirks->has_combo_dphy || !tcon->dphy)
> +		return;
> +
> +	phy_power_off(tcon->dphy);
> +	phy_exit(tcon->dphy);

Same comment here.

> +}
> +
>  static void sun4i_tcon_lvds_set_status(struct sun4i_tcon *tcon,
>  				       const struct drm_encoder *encoder,
>  				       bool enabled)
> @@ -1550,8 +1574,12 @@ static const struct sun4i_tcon_quirks sun9i_a80_tcon_tv_quirks = {
>  
>  static const struct sun4i_tcon_quirks sun20i_d1_lcd_quirks = {
>  	.has_channel_0		= true,
> +	.has_combo_dphy		= true,
> +	.supports_lvds		= true,
>  	.dclk_min_div		= 1,
>  	.set_mux		= sun8i_r40_tcon_tv_set_mux,
> +	.setup_lvds_phy		= sun20i_tcon_setup_lvds_dphy,
> +	.disable_lvds_phy	= sun20i_tcon_disable_lvds_dphy,
>  };
>  
>  /* sun4i_drv uses this list to check if a device node is a TCON */
> -- 
> 2.25.1
> 
> 

-- 
Paul Kocialkowski,

Independent contractor - sys-base - https://www.sys-base.io/
Free software developer - https://www.paulk.fr/

Expert in multimedia, graphics and embedded hardware support with Linux.

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