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

[Kuba Szczodrzyński]

W dniu 2025-11-20 o 07:24:53, Parthiban pisze:

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 <k...@szczodrzynski.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?

Hi,
Here's the DTS overlay I used to enable an LVDS panel on T113. You'll need to 
adapt the panel specification to your particular display.
I did not need to change the phy driver, so this extra requirement might be 
specific to A133.

/dts-v1/;
/plugin/;

&{/} {
        panel {
                compatible = "panel-lvds";
                data-mapping = "jeida-18";
                ddc-i2c-bus = <&i2c2>;

                port {
                        panel_input: endpoint {
                                remote-endpoint = <&tcon_lcd0_out_lvds>;
                        };
                };
        };
};

&tcon_lcd0 {
        pinctrl-names = "default";
        pinctrl-0 = <&lcd_lvds0_pins>;
};

&tcon_lcd0_out {
        reg = <1>;
        #address-cells = <1>;
        #size-cells = <0>;

        tcon_lcd0_out_lvds: endpoint@0 {
                reg = <0>;
                remote-endpoint = <&panel_input>;
        };
};

Regards
Kuba

Thanks,
Parthiban