Re: [PATCH 1/5] ARM: dts: at91: sama5d2_ptc_ek: fix sdmmc0 node description

From: <Eugen.Hristev@microchip.com>
To: <Ludovic.Desroches@microchip.com>, <Nicolas.Ferre@microchip.com>,
	<alexandre.belloni@bootlin.com>, <robh+dt@kernel.org>
Cc: <devicetree@vger.kernel.org>, <Tudor.Ambarus@microchip.com>,
	<linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<Codrin.Ciubotariu@microchip.com>,
	<Cristian.Birsan@microchip.com>
Subject: Re: [PATCH 1/5] ARM: dts: at91: sama5d2_ptc_ek: fix sdmmc0 node description
Date: Thu, 2 Apr 2020 10:27:54 +0000	[thread overview]
Message-ID: <8f7194a7-ad9e-5d27-7db1-d41a88d909de@microchip.com> (raw)
In-Reply-To: <5f762bdc-fe07-adbc-af8d-7670b5b4b286@microchip.com>

On 02.04.2020 13:07, Ludovic Desroches - M43218 wrote:
> On 4/2/2020 11:20 AM, Eugen Hristev - M18282 wrote:
>> On 02.04.2020 01:15, Ludovic Desroches wrote:
>>> Remove non-removable and mmc-ddr-1_8v properties from the sdmmc0
>>> node which come probably from an unchecked copy/paste.
>>>
>>> Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
>>> Fixes:42ed535595ec "ARM: dts: at91: introduce the sama5d2 ptc ek board"
>>> Cc: stable@vger.kernel.org # 4.19 and later
>>> ---
>>>     arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts | 2 --
>>>     1 file changed, 2 deletions(-)
>>>
>>> diff --git a/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts b/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts
>>> index 1c24ac8019ba7..772809c54c1f3 100644
>>> --- a/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts
>>> +++ b/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts
>>> @@ -125,8 +125,6 @@ sdmmc0: sdio-host@a0000000 {
>>>     			bus-width = <8>;
>>>     			pinctrl-names = "default";
>>>     			pinctrl-0 = <&pinctrl_sdmmc0_default>;
>>> -			non-removable;
>>> -			mmc-ddr-1_8v;
>>
>> Hi Ludovic,
>>
>> I am not sure about the removal of mmc-ddr-1_8v; this means eMMCs
>> connected on this slot won't work in high speed mode, some people use
>> eMMC to SD-Card adapters and stick them into SD-Card slots.
>> Would it be a problem to keep this property here ?
> 
> Hi Eugen,
> 
> It's not a problem to keep it, but I don't think it makes sense. In this
> case mmc-ddr-3_3v should be added too.
> 
> Will it work 'out of the box' with any eMMC to SD-Card adapters and
> eMMCs? I remember discussions where we said HW changes were needed to be
> able to select the voltage for the IOs other than using the VDDSEL
> signal of the controller.

Yes indeed , ddr-3_3v would be needed for those. I can follow up later 
with a patch to add that if required.

Thanks !

> 
> Regards
> 
> Ludovic
> 
> 
>>
>> Thanks,
>> Eugen
>>
>>>     			status = "okay";
>>>     		};
>>>     
>>>
>>
> 