Re: [PATCH v6 6/6] arm64: dts: qcom: Add device tree for Nord RRD board

[Shawn Guo]

On Thu, Jul 16, 2026 at 07:17:14PM +0200, Konrad Dybcio wrote:
> On 7/16/26 4:26 PM, Shawn Guo wrote:
> > Add initial device tree for the Qualcomm Dragonwing IQ10 RRD (Robotics
> > Reference Design) board, which is built on Nord Embedded variant. Enable
> > the debug UART, UFS storage, PMICs, I2C and SPI.
> > 
> > Co-developed-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Shawn Guo <shengchao.guo@xxxxxxxxxxxxxxxx>
> > ---
> 
> [...]
> 
> > +	/* PMIC A - Kobra_MM (PMM8650AU) - SID 0x0, Bus E0 */
> 
> This comment is very useful
> 
> > +	regulators-0 {
> > +		compatible = "qcom,pmm8654au-rpmh-regulators";
> > +		qcom,pmic-id = "A_E0";
> > +
> > +		/* LDO Regulators */
> 
> This is much less so
> 
> [...]

Indeed! Will drop.

> > +		vreg_l7a_1p2: ldo7 {
> > +			regulator-name = "vreg_l7a_1p2";
> > +			regulator-min-microvolt = <1200000>;
> > +			regulator-max-microvolt = <1200000>;
> > +			regulator-initial-mode = <RPMH_REGULATOR_MODE_HPM>;
> > +			regulator-always-on;
> > +			regulator-boot-on;
> > +			regulator-allow-set-load;
> 
> You made a lot of the regulators always-/boot-on - are you sure about
> each one of them?

As Bartosz replied, we will drop always-on/boot-on from vreg_l3e_1p8 and
vreg_l2i_1p2 regulator.

> > +			regulator-allowed-modes = <RPMH_REGULATOR_MODE_LPM
> > +						   RPMH_REGULATOR_MODE_HPM>;
> 
> It's commonplace to restrict regulators to HPM only because not all of
> the drivers that should be voting on desired load actually do it. Do
> you have any intermittent failures, particularly around PHYs?

We haven't seen failures like that. But to be on the side side, I would
rather follow your suggest to restrict UFS PHY regulators to be HPM only.

> 
> [...]
> 
> 
> > +&i2c7 {
> > +	clock-frequency = <400000>;
> > +
> > +	status = "okay";
> 
> It's commonplace to add comments like:
> 
> /* Type-C controller @ 0x15 */

We would like to drop untested/unused I2C buses/devices instead.

> 
> Otherwise this lgtm
> 
> Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>

Thank you, Konrad!

Shawn