Message-ID:
 <PN3P287MB1829A86F2A43F4A892151DC58B822@PN3P287MB1829.INDP287.PROD.OUTLOOK.COM>
Date: Thu, 1 May 2025 08:42:38 +0000
From: Tarang Raval <tarang.raval@...iconsignals.io>
To: Himanshu Bhavani <himanshu.bhavani@...iconsignals.io>
CC: "krzk+dt@...nel.org" <krzk+dt@...nel.org>, Rob Herring <robh@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>, Sascha
 Hauer <s.hauer@...gutronix.de>, Pengutronix Kernel Team
	<kernel@...gutronix.de>, Fabio Estevam <festevam@...il.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"imx@...ts.linux.dev" <imx@...ts.linux.dev>,
	"linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] arm64: dts: imx8mp-var-som: Fix LDO5 shutdown causing SD
 card timeout

Hi Himanshu,

Thanks for the update

> Fix SD card timeout issue caused by LDO5 regulator getting disabled
> after boot.
> 
> The kernel log shows LDO5 being disabled, which leads to a timeout
> on USDHC2:
> [   33.760561] LDO5: disabling
> [   81.119861] mmc1: Timeout waiting for hardware interrupt.
> 
> To prevent this, set regulator-boot-on and regulator-always-on for
> LDO5. Also add the vqmmc regulator to properly support 1.8V/3.3V
> signaling for USDHC2 using a GPIO-controlled regulator.
>
> Fixes: 6c2a1f4f71258 ("arm64: dts: imx8mp-var-som-symphony: Add Variscite Symphony board and VAR-SOM-MX8MP SoM")
> Signed-off-by: Himanshu Bhavani <himanshu.bhavani@...iconsignals.io>
> ---
> 
> kernel hangs during boot with the following logs:
> 
> [   33.760561] LDO5: disabling
> [   81.119861] mmc1: Timeout waiting for hardware interrupt.
> [   81.119872] mmc1: sdhci: ============ SDHCI REGISTER DUMP ===========
> [   81.119876] mmc1: sdhci: Sys addr:  0x00000010 | Version:  0x00000002
> [   81.119882] mmc1: sdhci: Blk size:  0x00000200 | Blk cnt:  0x00000010
> [   81.119886] mmc1: sdhci: Argument:  0x00844358 | Trn mode: 0x0000002b
> [   81.119891] mmc1: sdhci: Present:   0x01f88009 | Host ctl: 0x00000012
> [   81.119896] mmc1: sdhci: Power:     0x00000002 | Blk gap:  0x00000080
> [   81.119900] mmc1: sdhci: Wake-up:   0x00000008 | Clock:    0x0000003f
> [   81.119904] mmc1: sdhci: Timeout:   0x0000008f | Int stat: 0x00000000
> [   81.119908] mmc1: sdhci: Int enab:  0x117f100b | Sig enab: 0x117f100b
> [   81.119912] mmc1: sdhci: ACmd stat: 0x00000000 | Slot int: 0x00000502
> [   81.119917] mmc1: sdhci: Caps:      0x07eb0000 | Caps_1:   0x0000b407
> [   81.119921] mmc1: sdhci: Cmd:       0x0000193a | Max curr: 0x00ffffff
> [   81.119925] mmc1: sdhci: Resp[0]:   0x00000900 | Resp[1]:  0x0076b27f
> [   81.119929] mmc1: sdhci: Resp[2]:   0x325b5900 | Resp[3]:  0x00000900
> [   81.119933] mmc1: sdhci: Host ctl2: 0x00000008
> [   81.119937] mmc1: sdhci: ADMA Err:  0x00000003 | ADMA Ptr: 0x4003f204
> [   81.119941] mmc1: sdhci-esdhc-imx: ========= ESDHC IMX DEBUG STATUS DUMP =========
> [   81.119944] mmc1: sdhci-esdhc-imx: cmd debug status:  0x21b0
> [   81.119949] mmc1: sdhci-esdhc-imx: data debug status:  0x2200
> [   81.119954] mmc1: sdhci-esdhc-imx: trans debug status:  0x2300
> [   81.119959] mmc1: sdhci-esdhc-imx: dma debug status:  0x2400
> [   81.119964] mmc1: sdhci-esdhc-imx: adma debug status:  0x2594
> [   81.119970] mmc1: sdhci-esdhc-imx: fifo debug status:  0x2608
> [   81.119976] mmc1: sdhci-esdhc-imx: async fifo debug status:  0x2798
> [   81.119981] mmc1: sdhci: ===========================================
> 
> ---
>  arch/arm64/boot/dts/freescale/imx8mp-var-som.dtsi | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx8mp-var-som.dtsi b/arch/arm64/boot/dts/freescale/imx8mp-var-som.dtsi
> index b2ac2583a592..8d50e8382a1a 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mp-var-som.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mp-var-som.dtsi
> @@ -35,7 +35,6 @@ memory@...00000 {
>                        <0x1 0x00000000 0 0xc0000000>;
>          };
>  
> -
>          reg_usdhc2_vmmc: regulator-usdhc2-vmmc {
>                  compatible = "regulator-fixed";
>                  regulator-name = "VSD_3V3";
> @@ -46,6 +45,16 @@ reg_usdhc2_vmmc: regulator-usdhc2-vmmc {
>                  startup-delay-us = <100>;
>                  off-on-delay-us = <12000>;
>          };
> +
> +       reg_usdhc2_vqmmc: regulator-usdhc2-vqmmc {
> +               compatible = "regulator-gpio";
> +               regulator-name = "VSD_VSEL";
> +               regulator-min-microvolt = <1800000>;
> +               regulator-max-microvolt = <3300000>;
> +               gpio = <&gpio2 12 GPIO_ACTIVE_HIGH>;
> +               gpios-states = <1>;

You can remove gpios-states because we've already configured 
a pull-up in the pinmux, so this is not required.

> +               states = <3300000 0x0 1800000 0x1>;
> +       };
>  };
>
>  &A53_0 {
> @@ -158,6 +167,8 @@ ldo5: LDO5 {
>                                  regulator-name = "LDO5";
>                                  regulator-min-microvolt = <1800000>;
>                                  regulator-max-microvolt = <3300000>;
> +                               regulator-boot-on;
> +                               regulator-always-on;

Instead of using regulator-always-on for LDO5, we should set 
vin-supply = <&ldo5>; in the reg_usdhc2_vqmmc node. This 
cleanly defines the power dependency and avoids keeping 
LDO5 always on unnecessarily.

>                          };
>                  };
>          };
> @@ -205,6 +216,7 @@ &usdhc2 {
>          pinctrl-2 = <&pinctrl_usdhc2_200mhz>, <&pinctrl_usdhc2_gpio>;
>          cd-gpios = <&gpio1 14 GPIO_ACTIVE_LOW>;
>          vmmc-supply = <&reg_usdhc2_vmmc>;
> +       vqmmc-supply = <&reg_usdhc2_vqmmc>;
>          bus-width = <4>;
>          status = "okay";
>  };
> --
> 2.34.1

Otherwise LGTM.

Best Regards,
Tarang

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