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Date: Thu, 11 Apr 2024 08:51:52 +0200
From: Stephan Gerhold <stephan@gerhold.net>
To: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
Cc: Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] arm64: dts: qcom: sa8155p-adp: use correct gpio for
 SDHC2 CD
Message-ID: <ZheIiMZaTAFrxCOm@gerhold.net>
References: <20240410134022.732767-1-volodymyr_babchuk@epam.com>
 <Zhb53i8-pJhDMVZM@gerhold.net>
 <87cyqw6fvh.fsf@epam.com>
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On Wed, Apr 10, 2024 at 09:57:02PM +0000, Volodymyr Babchuk wrote:
> Stephan Gerhold <stephan@gerhold.net> writes:
> > On Wed, Apr 10, 2024 at 01:41:30PM +0000, Volodymyr Babchuk wrote:
> >> Card Detect pin for SHDC2 on SA8155P-ADP is connected to GPIO4 of
> >> PMM8155AU_1, not to internal TLMM. This change fixes two issues at
> >> once: not working ethernet (because GPIO4 is used for MAC TX) and SD
> >> detection.
> >> 
> >> Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
> >> ---
> >>  arch/arm64/boot/dts/qcom/sa8155p-adp.dts | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >> 
> >> diff --git a/arch/arm64/boot/dts/qcom/sa8155p-adp.dts b/arch/arm64/boot/dts/qcom/sa8155p-adp.dts
> >> index 5e4287f8c8cd1..6b08ce246b78c 100644
> >> --- a/arch/arm64/boot/dts/qcom/sa8155p-adp.dts
> >> +++ b/arch/arm64/boot/dts/qcom/sa8155p-adp.dts
> >> @@ -384,7 +384,7 @@ &remoteproc_cdsp {
> >>  &sdhc_2 {
> >>  	status = "okay";
> >>  
> >> -	cd-gpios = <&tlmm 4 GPIO_ACTIVE_LOW>;
> >> +	cd-gpios = <&pmm8155au_1_gpios 4 GPIO_ACTIVE_LOW>;
> >
> > Good catch!
> 
> Yeah... It took time to understand why ethernet is not working
> sometimes. It appeared that there were race between SDHC and MAC
> initialization.
> 
> >
> >>  	pinctrl-names = "default", "sleep";
> >>  	pinctrl-0 = <&sdc2_on>;
> >>  	pinctrl-1 = <&sdc2_off>;
> >
> > These two pinctrl configure "gpio96" for "sd-cd-pins". Yet another wrong
> > GPIO? Should probably drop that and add proper pinctrl for the actual
> > GPIO in the PMIC. Seems like Qualcomm configured the PMIC GPIO with
> > pull-up downstream [1] (not sure if this is the right file). It might be
> > redundant if there is an external pull-up on the board, but only the
> > schematic could tell that for sure.
> 
> If I only had schematic for this board... gpio96 puzzles me as well. I
> can understand where wrong GPIO4 come from. But gpio96 origin is
> completely unclear. I have user manual for the board, it mention
> functions of some GPIOs, but there is nothing about gpio96. Anyways, I
> removed it from the DTS (see diff below) and I see no issues with SD card.
> 

I believe this might have been mistakenly copied from some SM8150
example, there you can occasionally find cd-gpios defined as <&tlmm 96>.
E.g. in sm8150-pinctrl.dtsi downstream:

https://git.codelinaro.org/clo/la/kernel/msm-4.14/-/blob/484af352989c912db8f3b6393fc090006029066f/arch/arm64/boot/dts/qcom/sm8150-pinctrl.dtsi#L70-81

> > FWIW: Looking closer at the broken commit, the regulator voltage setup
> > of &sdhc_2 looks suspicious too. Typically one would want a 1.8V capable
> > regulator for the vqmmc-supply to properly use ultra high-speed modes,
> > but &vreg_l13c_2p96 seems to be configured with 2.504V-2.960V at the
> > moment. On downstream it seems to be 1.8V-2.96V [2] (again, not sure if
> > this is the right file). I would recommend re-checking this too and
> > testing if UHS cards are detected correctly (if you have the board).
> 
> This is actually a good catch. I changed the voltage range to 1.8V-2.96V and
> now my card detects in UHS/SDR104 mode. Prior to this change it worked only
> in HS mode.
> 

Yay!

> > &vreg_l17a_2p96 has the same 2.504V-2.960V, but has 2.704V-2.960V
> > downstream [3]. This is close at least, might be fine as-is (but I'm not
> > convinced there is a good reason to differ there).
> >
> 
> Well, I believe that downstream configuration is more correct, but I
> can't prove it, so I'll leave it as is.
> 

Ack.

> Diff for additional changes looks like this:
> 
> diff --git a/arch/arm64/boot/dts/qcom/sa8155p-adp.dts b/arch/arm64/boot/dts/qcom/sa8155p-adp.dts
> index 6b08ce246b78c..b2a3496ff68ad 100644
> --- a/arch/arm64/boot/dts/qcom/sa8155p-adp.dts
> +++ b/arch/arm64/boot/dts/qcom/sa8155p-adp.dts
> @@ -283,7 +283,7 @@ vreg_l12c_1p808: ldo12 {
>  
>                 vreg_l13c_2p96: ldo13 {
>                         regulator-name = "vreg_l13c_2p96";
> -                       regulator-min-microvolt = <2504000>;
> +                       regulator-min-microvolt = <1800000>;
>                         regulator-max-microvolt = <2960000>;
>                         regulator-initial-mode = <RPMH_REGULATOR_MODE_HPM>;
>                 };
> @@ -386,8 +386,8 @@ &sdhc_2 {
>  
>         cd-gpios = <&pmm8155au_1_gpios 4 GPIO_ACTIVE_LOW>;
>         pinctrl-names = "default", "sleep";
> -       pinctrl-0 = <&sdc2_on>;
> -       pinctrl-1 = <&sdc2_off>;
> +       pinctrl-0 = <&sdc2_on &pmm8155au_1_sdc2_on>;
> +       pinctrl-1 = <&sdc2_off &pmm8155au_1_sdc2_off>;
>         vqmmc-supply = <&vreg_l13c_2p96>; /* IO line power */
>         vmmc-supply = <&vreg_l17a_2p96>;  /* Card power line */
>         bus-width = <4>;
> @@ -505,13 +505,6 @@ data-pins {
>                         bias-pull-up;           /* pull up */
>                         drive-strength = <16>;  /* 16 MA */
>                 };
> -
> -               sd-cd-pins {
> -                       pins = "gpio96";
> -                       function = "gpio";
> -                       bias-pull-up;           /* pull up */
> -                       drive-strength = <2>;   /* 2 MA */
> -               };
>         };
>  
>         sdc2_off: sdc2-off-state {
>         @@ -532,13 +525,6 @@ data-pins {
>                         bias-pull-up;           /* pull up */
>                         drive-strength = <2>;   /* 2 MA */
>                 };
> -
> -               sd-cd-pins {
> -                       pins = "gpio96";
> -                       function = "gpio";
> -                       bias-pull-up;           /* pull up */
> -                       drive-strength = <2>;   /* 2 MA */
> -               };
>         };
>  
>         usb2phy_ac_en1_default: usb2phy-ac-en1-default-state {
> @@ -604,3 +590,25 @@ phy-reset-pins {
>                 };
>         };
>  };
> +
> +&pmm8155au_1_gpios {
> +       pmm8155au_1_sdc2_on: pmm8155au_1-sdc2-on-state {
> +               sd-cd-pin {
> +                       pins = "gpio4";
> +                       function = "normal";
> +                       input-enable;
> +                       bias-pull-up;
> +                       power-source = <0>;
> +               };
> +       };
> +
> +       pmm8155au_1_sdc2_off: pmm8155au_1-sdc2-off-state {
> +               sd-cd-pin {
> +                       pins = "gpio4";
> +                       function = "normal";
> +                       input-enable;
> +                       bias-pull-up;
> +                       power-source = <0>;
> +               };
> +       };

Since the configuration is the same for both on and off state, you can
combine this into one node and then reference it twice. Also, the single
subnode should not be needed:

	pmm8155au_1_sdc2_cd: pmm8155au_1-sdc2-cd-state {
		pins = "gpio4";
		function = "normal";
		input-enable;
		bias-pull-up;
		power-source = <0>;
	};

&sdhc_2 {
	pinctrl-0 = <&sdc2_on &pmm8155au_1_sdc2_cd>;
	pinctrl-1 = <&sdc2_off &pmm8155au_1_sdc2_cd>;
};

Looks good to me otherwise, thanks for cleaning this up!

> 
> I am planning to send v2 tomorrow.
> 

Thanks!
Stephan