Re: [PATCH v2 5/5] arm64: dts: renesas: Add LCDC overlays for RZ/T2H and RZ/N2H EVKs with ADV7513

Hi Geert,

Thank you for the review. Sorry for the delayed response.

On Thu, Aug 13, 2026 at 12:56 PM Geert Uytterhoeven
<[email protected]> wrote:
>
> Hi Prabhakar,
>
> On Mon, 15 Jun 2026 at 13:55, Prabhakar <[email protected]> wrote:
> > From: Lad Prabhakar <[email protected]>
> >
> > Add DT overlay support enabling the DU/LCDC pipeline on the RZ/T2H
> > (r9a09g077) and RZ/N2H (r9a09g087) evaluation kits when fitted with a
> > CN15/CN20 ADV7513 HDMI transmitter.
> >
> > Move the LED8 and LED9 preprocessor conditionals inside the node
> > definitions so that the nodes remain present in the base DTS. This
> > allows the LCDC overlay to reference and disable them when their pins
> > are reassigned to display functions.
> >
> > According to the hardware manual, the LCDC pins should use slew-rate
> > setting 1 (fast). However, testing on the RZ/T2H and RZ/N2H EVKs with
> > the ADV7513 HDMI transmitter showed unstable display output with visible
> > screen flicker when configured for fast slew-rate operation. Configure
> > the LCDC pins with slew-rate setting 0 (slow) instead, which provides
> > stable display output on the evaluation platforms.
> >
> > Signed-off-by: Lad Prabhakar <[email protected]>
>
> Thanks for your patch!
>
> > --- /dev/null
> > +++ b/arch/arm64/boot/dts/renesas/r9a09g077m44-evk-cn15-lcdc.dtso
>
> > +/*
> > + * RZ/T2H LCDC configuration:
> > + * ----------------------------------------------------------
> > + * Function        Pin     SW Setting
> > + * ----------------------------------------------------------
> > + * LCDC_DATG0     P11_0, SW6[3]: OFF, SW6[4]: ON, SW6[5]: OFF
> > + * LCDC_DATB1     P18_0, SW8[3]: OFF, SW8[4]: ON
> > + * LCDC_DATB2     P18_1, SW8[1]: OFF, SW8[2]: ON
> > + * HEADER_IRQ8    P22_6, SW2[1]: ON, SW2[2]: OFF
>
> What is IRQ8 connected to on the display board?
> It is not described in the .dts[io].
>
Actually this is connected to pin 28 (INT) of the ADV7513 chip.

> BTW, r9a09g077m44-rzt2h-evk.dts uses a mix of "SWx[y]" and "SWx-y" (and
> tables), which makes it harder than needed to see which functionality
> is affected by a given switch.
>
I'll add a patch to use consistent notation.

> > + */
> > +#include "rzt2h-n2h-evk-du-adv7513.dtsi"
>
> In case of dynamic overlays, any conflicting pins must be disabled
> first, so please move this #include to the end of this file.
>
> > +
> > +&{/leds/led-4} {
> > +       /* P18_0 is used for DU function LCDC_DATB1. */
> > +       status = "disabled";
> > +};
> > +
> > +&{/leds/led-5} {
> > +       /* P18_1 is used for DU function LCDC_DATB2. */
> > +       status = "disabled";
> > +};
> > +
> > +/*
> > + * Disable SDHI0 as SW2 settings for eMMC/SD card conflict with DU pin
> > + * settings.
> > + */
> > +&sdhi0 {
> > +       status = "disabled";
> > +};
>
> > --- /dev/null
> > +++ b/arch/arm64/boot/dts/renesas/r9a09g087m44-evk-cn20-lcdc.dtso
>
> > +/*
> > + * RZ/N2H LCDC configuration:
> > + * ----------------------------------------------------------
> > + * Function        Pin     SW Setting
> > + * ----------------------------------------------------------
> > + * LCDC_DATG0     P11_0, DSW12[3]: ON, DSW12[4]: OFF
> > + * LCDC_DATG3     P14_3, DSW18[5]: OFF, DSW18[6]: ON
>
> and DSW19[3]: OFF, DSW19[4]: ON?
>
Ack.

> > + * LCDC_DATG6     P14_6, DSW15[8]: ON, DSW15[9]: OFF, DSW15[10]: OFF
> > + * LCDC_DATB2     P18_1, DSW18[9]: OFF, DSW18[10]: ON
> > + * I2C_SDA1       P03_3, DSW7[1]: ON, DSW7[2]: OFF
> > + * I2C_SCL1       P03_4, DSW7[3]: ON, DSW7[4]: OFF
>
> I2C_SDA1 and I2C_SCL1 are exchanged?
>
Ack.

> BTW, r9a09g087m44-rzn2h-evk.dts uses a mix of "SWx[y]" and "SWx-y" (and
> tables), which makes it harder than needed to see which functionality
> is affected by a given switch.
>
I'll update it to be consistent.

> > + * ------------------------------------------------
> > + */
> > +
> > +#include "rzt2h-n2h-evk-du-adv7513.dtsi"
>
> In case of dynamic overlays, any conflicting pins must be disabled
> first, so please move this #include to the end of this file.
>
Ok.

> > +
> > +&{/keys/key-1} {
> > +       /* P18_2 is used for DU function LCDC_DATB3. */
> > +       status = "disabled";
> > +};
> > +
> > +&{/leds/led-4} {
> > +       /* P18_1 is used for DU function LCDC_DATB2. */
> > +       status = "disabled";
> > +};
> > +
> > +&{/leds/led-7} {
> > +       /* P14_3 is used for DU function LCDC_DATG3. */
> > +       status = "disabled";
> > +};
> > +
> > +&{/leds/led-8} {
> > +       /* P14_6 is used for DU function LCDC_DATG6. */
> > +       status = "disabled";
> > +};
> > +
> > +&i2c0 {
> > +       status = "disabled";
>
> Needs the same comment as led-8 above?
>
Ok, I will add a comment for it.

Cheers,
Prabhakar