Re: [PATCH 1/3 v2] ARM: dts: rk3288-tinker.dtsi: Fix SD card detection

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On 2019-02-24 20:35, David Summers wrote:
> On 24/02/2019 19:26, Jonas Karlman wrote:
>> On 2019-02-22 19:47, David Summers wrote:
>>> The Problem:
>>>
>>> On ASUS Tinker Board S, when booting from the eMMC, and there is no
>>> card sd slot, then there are constant errors.
>>>
>>> Cause:
>>>
>>> Thanks must go to Robin Murphy @ ARM for idenifying the problem. The
>>> rk808 on the Tinker Board and Tinker Board S has many regulators, one
>>> vccio_sd powers the IO for the sd card. Unfortunatly this is also used
>>> in the card detect. Now when no card is install, the regulator is
>>> powered down. This means that the card detect floats, and this means
>>> random card detection.
>>>
>>> The Solution:
>>>
>>> Make sure that the sd IO is always powered, this means card detection
>>> is always active, which is what should be done on a board with an sd
>>> slot, which both the Tinker Board and Tinker Board S are. Hence change
>>> is made to the .dtsi which takes effect on all Tinker Boards as
>>> required.
>>>
>>> The change also adds "regulator-boot-on" the Tinker Board boot from
>>> uboot, and the sd card is always one option. Hence the IO must be
>>> powered in uboot, and so setting this flag.
>>>
>>> Also removed is "disable-wp" the micro sd card which are used have no
>>> write  protection, so the concept doesn't mean anything, and the
>>> Tinker Boards work without this. Hence it is removed to simply.
>>>
>>> This change came from ArchLinux Arm, but we note it is the fix also
>>> used by Armbian:
>>>
>>> https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FMiouyouyou%2FRockMyy%2Fblob%2Fmaster%2Fpatches%2Fkernel%2Fv5.0%2FDTS%2F0016-ARM-DTSI-rk3288-tinker-Setting-up-the-SD-regulators.patch&data=02%7C01%7C%7Cf5937082939e4163c84b08d69a8f3b61%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636866337295767294&sdata=tK8QE3bsG9LW%2FJcvFzLKa8%2BPj5u%2F8exbEn8m2vqKly0%3D&reserved=0
>>>
>>> Signed-off-by: David Summers <beagleboard@xxxxxxxxxxxxxxxxxxx>
>>> ---
>>>   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..6b7e55085b0c 100644
>>> --- a/arch/arm/boot/dts/rk3288-tinker.dtsi
>>> +++ b/arch/arm/boot/dts/rk3288-tinker.dtsi
>>> @@ -254,6 +254,8 @@
>>>   			};
>>>   
>>>   			vccio_sd: LDO_REG5 {
>>> +				regulator-always-on;
>>> +				regulator-boot-on;
>>>   				regulator-min-microvolt = <1800000>;
>>>   				regulator-max-microvolt = <3300000>;
>>>   				regulator-name = "vccio_sd";
>>> @@ -431,7 +433,6 @@
>>>   	cap-mmc-highspeed;
>>>   	cap-sd-highspeed;
>>>   	card-detect-delay = <200>;
>>> -	disable-wp;			/* wp not hooked up */
>> I think disable-wp correctly describes that wp is not expected to work and should not be removed.
>>
>>  From comment in mmc_sd_get_ro():
>> "Some systems don't feature a write-protect pin and don't need one.
>> E.g. because they only have micro-SD card slot. For those systems
>> assume that the SD card is always read-write."
>>
>> Without disable-wp core will call dw_mci_get_ro() to get wp status.
>>
>>
>> This patch also fixes reboot when booting from sd-card and having emmc zeroed out.
>>
>> Tested-by: Jonas Karlman <jonas@xxxxxxxxx>
>>
>> Regards,
>> Jonas
>>
>>>   	pinctrl-names = "default";
>>>   	pinctrl-0 = <&sdmmc_clk &sdmmc_cmd &sdmmc_cd &sdmmc_bus4>;
>>>   	status = "okay";
> Hi Jonas,
>
> Thanks for testing - did you get an error with "disable-wp" ?
>
> We tested this with @TheSaint On ArchLinux Arm, and it worked!
>
> With the "regulator-boot-on" and on reboot, it should keep power on the 
> sd card - so reboot should work.

I tested both with and without "disable-wp" removed and both works without error.
SD-card reboots now works as it should thanks to "regulator-always-on" and "regulator-boot-on", I only tested using both.

On a side note I have also been testing [1] to make reboot with UHS signal voltage work and will send out a RFC v2
after I have concluded testing on my other devices supporting UHS signal voltage.

[1] https://github.com/Kwiboo/linux-rockchip/compare/patch-rk-5.x-tinker-uhs%5E%5E%5E...patch-rk-5.x-tinker-uhs

Regards,
Jonas

>
> Regards,
>
> David.
>
>


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