linux-kernel - Re: [PATCH v3 1/6] phy: allwinner: phy-sun6i-mipi-dphy: Support LVDS in combo D-PHY

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <6d421d06-c534-40f3-8732-8f80a29b6821@linumiz.com>
Date: Thu, 20 Nov 2025 07:24:53 +0100
From: Parthiban <parthiban@...umiz.com>
To: Kuba Szczodrzyński <kuba@...zodrzynski.pl>,
 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>
Cc: parthiban@...umiz.com, 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,
 paulk@...-base.io
Subject: Re: [PATCH v3 1/6] phy: allwinner: phy-sun6i-mipi-dphy: Support LVDS
 in combo D-PHY

Dear Kuba,

Thanks for your efforts.

On 11/16/25 2:47 PM, Kuba Szczodrzyński wrote:
> Some Allwinner chips (notably the D1s/T113 and the A100) have a "combo
> MIPI DSI D-PHY" which is required when using single-link LVDS0.
> 
> In this mode, the DSI peripheral is not used and the PHY is not
> configured for DSI. Instead, the COMBO_PHY_REGx registers are set to
> enable LVDS operation.
> 
> Enable the PHY driver to work in LVDS mode on chips with a combo D-PHY.
> 
> Also change the SUN50I_COMBO_PHY_REG1 macro names to reflect the correct
> register name.
> 
> Signed-off-by: Kuba Szczodrzyński <kuba@...zodrzynski.pl>
> ---
>  drivers/phy/allwinner/phy-sun6i-mipi-dphy.c | 70 ++++++++++++++++++++-
>  1 file changed, 68 insertions(+), 2 deletions(-)

I tried integrating your changes in A133 display pipeline and I couldn't get the LVDS working.
Am still narrowing down what is missing in your patch. Driver registration is success and I
can see /dev/fb0 as well. But nothing on the display itself.

But with below changes from my patch,

diff --git a/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c b/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c
index 36eab95271b2..d164b2ea5dfd 100644
--- a/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c
+++ b/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c
@@ -314,13 +314,11 @@ static void sun50i_a100_mipi_dphy_tx_power_on(struct sun6i_dphy *dphy)
        /* Disable sigma-delta modulation. */
        regmap_write(dphy->regs, SUN50I_DPHY_PLL_REG2, 0);
 
-       regmap_update_bits(dphy->regs, SUN6I_DPHY_ANA4_REG,
-                          SUN6I_DPHY_ANA4_REG_EN_MIPI,
-                          SUN6I_DPHY_ANA4_REG_EN_MIPI);
-
        regmap_update_bits(dphy->regs, SUN50I_COMBO_PHY_REG0,
+                          SUN50I_COMBO_PHY_REG0_EN_LVDS |
                           SUN50I_COMBO_PHY_REG0_EN_MIPI |
                           SUN50I_COMBO_PHY_REG0_EN_COMBOLDO,
+                          SUN50I_COMBO_PHY_REG0_EN_LVDS |
                           SUN50I_COMBO_PHY_REG0_EN_MIPI |
                           SUN50I_COMBO_PHY_REG0_EN_COMBOLDO);
 
@@ -528,6 +526,22 @@ static int sun6i_dphy_exit(struct phy *phy)
        return 0;
 }

LVDS works fine.

Could you please share the diff of your dts / dtsi?

Thanks,
Parthiban