linux-kernel - Re: [PATCH 07/17] arm64: dts: exynos: gs101: Add ufs, ufs-phy and ufs regulator dt nodes

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Date: Thu, 18 Apr 2024 14:20:15 +0100
From: Peter Griffin <peter.griffin@...aro.org>
To: Krzysztof Kozlowski <krzk@...nel.org>
Cc: mturquette@...libre.com, sboyd@...nel.org, robh@...nel.org, 
	krzk+dt@...nel.org, conor+dt@...nel.org, vkoul@...nel.org, kishon@...nel.org, 
	alim.akhtar@...sung.com, avri.altman@....com, bvanassche@....org, 
	s.nawrocki@...sung.com, cw00.choi@...sung.com, jejb@...ux.ibm.com, 
	martin.petersen@...cle.com, chanho61.park@...sung.com, ebiggers@...nel.org, 
	linux-scsi@...r.kernel.org, linux-phy@...ts.infradead.org, 
	devicetree@...r.kernel.org, linux-clk@...r.kernel.org, 
	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, tudor.ambarus@...aro.org, 
	andre.draszik@...aro.org, saravanak@...gle.com, willmcvicker@...gle.com
Subject: Re: [PATCH 07/17] arm64: dts: exynos: gs101: Add ufs, ufs-phy and ufs
 regulator dt nodes

Hi Krzysztof,

Thanks for your review feedback.

On Fri, 5 Apr 2024 at 08:53, Krzysztof Kozlowski <krzk@...nel.org> wrote:
>
> On 04/04/2024 14:25, Peter Griffin wrote:
> > Enable the ufs controller, ufs phy and ufs regulator in device tree.
> >
> > Signed-off-by: Peter Griffin <peter.griffin@...aro.org>
> > ---
> >  .../boot/dts/exynos/google/gs101-oriole.dts   | 17 +++++++++
> >  arch/arm64/boot/dts/exynos/google/gs101.dtsi  | 35 +++++++++++++++++++
>
> If you wish you can split DTSI and DTS into separate patches. Up to you.

Thanks for the heads up
>
> >  2 files changed, 52 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts b/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts
> > index 6be15e990b65..986eb5c9898a 100644
> > --- a/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts
> > +++ b/arch/arm64/boot/dts/exynos/google/gs101-oriole.dts
> > @@ -53,6 +53,14 @@ button-power {
> >                       wakeup-source;
> >               };
> >       };
> > +
> > +     ufs_0_fixed_vcc_reg: regulator-0 {
> > +             compatible = "regulator-fixed";
> > +             regulator-name = "ufs-vcc";
> > +             gpio = <&gpp0 1 0>;
>
> Use defines for GPIO flags,

Will fix in v2

> but more important: are you sure this is not
> coming from a PMIC? What's the voltage? It looks like a stub for missing
> PMIC, because UFS voltages are usually provided by PMIC.

UFS vcc is 1.2v. The gpio signal from gs101 SoC is called BOOTLD0, and
it is connected to slave pmic (S2MPG11) UFS_EN signal which is a gpio
enabled voltage rail for UFS (LDO8S).

The downstream driver code declares the UFS supply as regulator-fixed
even though it has a fully featured regulator driver for the pmic,
with the LDO8S regulator exposed. Checking the DT for the pmic the min
and max volt are different, so using regulator-fixed seems wrong for
downstream.

s_ldo8_reg: LDO8S {
    regulator-name = "S2MPG11_LDO8";
    regulator-min-microvolt = <1127800>;
    regulator-max-microvolt = <1278600>;
    regulator-always-on;
    regulator-initial-mode = <SEC_OPMODE_SUSPEND>;
    channel-mux-selection = <0x28>;
    schematic-name = "L8S_UFS_VCCQ";
    subsys-name = "UFS";
 };

So I think you're correct this is a stub pending full pmic support. I
propose in v2 to add a comment similar to what we have in
exynos850-e850-96.dts today above the regulator-fixed node like /*
TODO: Remove this once PMIC is implemented  */?

regards,

Peter.




>
> > +             regulator-boot-on;
> > +             enable-active-high;
> > +     };
> >  };
> >
> >  &ext_24_5m {
> > @@ -106,6 +114,15 @@ &serial_0 {
> >       status = "okay";
> >  };
> >
> > +&ufs_0 {
> > +     status = "okay";
> > +     vcc-supply = <&ufs_0_fixed_vcc_reg>;
> > +};
> > +
> > +&ufs_0_phy {
> > +     status = "okay";
> > +};
> > +
> >  &usi_uart {
> >       samsung,clkreq-on; /* needed for UART mode */
> >       status = "okay";
> > diff --git a/arch/arm64/boot/dts/exynos/google/gs101.dtsi b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> > index 608369cec47b..9c94829bf14c 100644
> > --- a/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> > +++ b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> > @@ -1277,6 +1277,41 @@ pinctrl_hsi2: pinctrl@...40000 {
> >                       interrupts = <GIC_SPI 503 IRQ_TYPE_LEVEL_HIGH 0>;
> >               };
> >
> > +             ufs_0_phy: phy@...04000 {
> > +                     compatible = "google,gs101-ufs-phy";
> > +                     reg = <0x14704000 0x3000>;
> > +                     reg-names = "phy-pma";
> > +                     samsung,pmu-syscon = <&pmu_system_controller>;
> > +                     #phy-cells = <0>;
> > +                     clocks = <&ext_24_5m>;
> > +                     clock-names = "ref_clk";
> > +                     status = "disabled";
> > +             };
> > +
> > +             ufs_0: ufs@...00000 {
> > +                     compatible = "google,gs101-ufs";
> > +
>
> Drop blank line.
>
> > +                     reg = <0x14700000 0x200>,
> > +                           <0x14701100 0x200>,
> > +                           <0x14780000 0xa000>,
> > +                           <0x14600000 0x100>;
>
>
> Best regards,
> Krzysztof
>