Re: [PATCH v3 1/3] arm: dts: rk3288-tinker.dtsi: Fix SD card detection

From: Heiko Stuebner <heiko@sntech.de>
To: David Summers <beagleboard@davidjohnsummers.uk>
Cc: devicetree@vger.kernel.org, ulf.hansson@linaro.org,
	Robin Murphy <robin.murphy@arm.com>,
	linux-mmc@vger.kernel.org, jh80.chung@samsung.com,
	linux-rockchip@lists.infradead.org, robh+dt@kernel.org,
	frowand.list@gmail.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 1/3] arm: dts: rk3288-tinker.dtsi: Fix SD card detection
Date: Tue, 12 Mar 2019 15:08:15 +0100	[thread overview]
Message-ID: <10436027.DUyLE1RSiR@phil> (raw)
In-Reply-To: <20190309153923.22806-1-beagleboard@davidjohnsummers.uk>

Am Samstag, 9. März 2019, 16:39:21 CET schrieb David Summers:
> The Problem:
> 
> On ASUS Tinker Board S, when booting from the eMMC, and there is card
> in the sd slot, there are constant errors.
> 
> Also when warm reboot, uboot can not access the sd slot
> 
> Cause:
> 
> Identified by Robin Murphy @ ARM. The Card Detect on rk3288
> devices is pulled up by vccio-sd; so when the regulator powers this
> off, card detect gives spurious errors. A second problem, is during
> power down, vccio-sd apprears to be powered down. This causes a
> problem when warm rebooting from the sd card. This was identified by
> Jonas Karlman.
> 
> History:
> 
> A common fault on these rk3288 board, which impliment the reference
> design.
> 
> When this arose before:
> 
> http://lists.infradead.org/pipermail/linux-arm-kernel/2014-August/281153.html
> 
> And Ulf and Jaehoon clearly said this was a broken card detect design,
> which should be solved via polling
> 
> Solution:
> 
> Hence broken-cd is set as a property. This cures the errors. The
> powering down of vccio-sd during reboot is cured by adding
> regulator-boot-on.
> 
> This solutions has been fairly widely reviewed and tested.
> 
> Signed-off-by: David Summers <beagleboard@davidjohnsummers.uk>
> Reviewed by: Robin Murphy <robin.murphy@arm.com>
> Reviewed by: Jonas Karlman <jonas@kwiboo.se>
> Test by: TheSaint @ ArchLinux Arm

please follow patch submission guidelines, here it would be
Tested-by: ... with an actual Name + mail address

Also I did try to go through the way big mail thread but didn't
find an actual "Reviewed-by" from Robin Murphy, similar to what
he pointed out in patch2

Other than that and including the past discussions, this looks good.

Heiko

> ---
>  arch/arm/boot/dts/rk3288-tinker.dtsi | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/rk3288-tinker.dtsi b/arch/arm/boot/dts/rk3288-tinker.dtsi
> index aa107ee41b8b..ef653c3209bc 100644
> --- a/arch/arm/boot/dts/rk3288-tinker.dtsi
> +++ b/arch/arm/boot/dts/rk3288-tinker.dtsi
> @@ -254,6 +254,7 @@
>  			};
>  
>  			vccio_sd: LDO_REG5 {
> +				regulator-boot-on;
>  				regulator-min-microvolt = <1800000>;
>  				regulator-max-microvolt = <3300000>;
>  				regulator-name = "vccio_sd";
> @@ -430,7 +431,7 @@
>  	bus-width = <4>;
>  	cap-mmc-highspeed;
>  	cap-sd-highspeed;
> -	card-detect-delay = <200>;
> +	broken-cd;
>  	disable-wp;			/* wp not hooked up */
>  	pinctrl-names = "default";
>  	pinctrl-0 = <&sdmmc_clk &sdmmc_cmd &sdmmc_cd &sdmmc_bus4>;
> 

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