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From: Peter Geis <pgwipeout@gmail.com>
To: Aapo Vienamo <avienamo@nvidia.com>,
	Thierry Reding <thierry.reding@gmail.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Mikko Perttunen <mperttunen@nvidia.com>,
	linux-mmc@vger.kernel.org, devicetree@vger.kernel.org,
	linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/8] arm64: dts: tegra186: Add SDMMC4 DQS trim value
Date: Thu, 9 Aug 2018 08:23:16 -0400	[thread overview]
Message-ID: <03fc6726-25ff-20de-d271-ebae19b753c7@gmail.com> (raw)
In-Reply-To: <20180809150226.64657f56@dhcp-10-21-25-168>



On 08/09/2018 08:02 AM, Aapo Vienamo wrote:
> On Thu, 9 Aug 2018 13:49:22 +0200
> Thierry Reding <thierry.reding@gmail.com> wrote:
> 
>> On Tue, Aug 07, 2018 at 05:00:01PM +0300, Aapo Vienamo wrote:
>>> Add the HS400 DQS trim value for Tegra186 SDMMC4.
>>>
>>> Signed-off-by: Aapo Vienamo <avienamo@nvidia.com>
>>> ---
>>>   arch/arm64/boot/dts/nvidia/tegra186.dtsi | 1 +
>>>   1 file changed, 1 insertion(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/nvidia/tegra186.dtsi b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
>>> index 6e9ef26..9e07bc6 100644
>>> --- a/arch/arm64/boot/dts/nvidia/tegra186.dtsi
>>> +++ b/arch/arm64/boot/dts/nvidia/tegra186.dtsi
>>> @@ -313,6 +313,7 @@
>>>   		nvidia,pad-autocal-pull-down-offset-1v8-timeout = <0x0a>;
>>>   		nvidia,default-tap = <0x5>;
>>>   		nvidia,default-trim = <0x9>;
>>> +		nvidia,dqs-trim = <63>;
>>>   		status = "disabled";
>>>   	};
>>>     
>>
>> Isn't this technically dependent on the board layout and as such would
>> belong in the board DTS file? Or does this value work on all existing
>> Tegra186 platforms?
> 
> This value is specified as part of the controller initialization
> sequence in the TRM. I've understood that this (and other tap and trim)
> value(s) are used for compensating the propagation delay differences
> that are caused by the internal SoC layout.
> 
>   -Aapo
> --

The Tegra2 and Tegra3 TRMs also specify recommended DQS values, and I am 
working on at least one device that differs in the platform data from 
the default value.
I see that you mentioned this is for the newer devices that support 
HS200/HS400 modes, but does it enable setting DQS on older devices?

  reply	other threads:[~2018-08-09 12:23 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-07 13:59 [PATCH 0/8] Tegra SDHCI support HS400 on Tegra210 and Tegra186 Aapo Vienamo
2018-08-07 13:59 ` [PATCH 1/8] dt-bindings: mmc: Add DQS trim value to Tegra SDHCI Aapo Vienamo
2018-08-09 11:36   ` Thierry Reding
2018-08-09 11:45     ` Aapo Vienamo
2018-08-09 13:46       ` Thierry Reding
2018-08-09 14:06         ` Aapo Vienamo
2018-08-09 14:09           ` Thierry Reding
2018-08-07 13:59 ` [PATCH 2/8] mmc: tegra: Parse and program DQS trim value Aapo Vienamo
2018-08-09 11:40   ` Thierry Reding
2018-08-09 11:42   ` Thierry Reding
2018-08-07 13:59 ` [PATCH 3/8] mmc: tegra: Implement HS400 enhanced strobe Aapo Vienamo
2018-08-09 11:43   ` Thierry Reding
2018-08-09 12:22     ` Aapo Vienamo
2018-08-09 13:47       ` Thierry Reding
2018-08-07 14:00 ` [PATCH 4/8] mmc: tegra: Implement HS400 delay line calibration Aapo Vienamo
2018-08-09 11:48   ` Thierry Reding
2018-08-09 12:29     ` Aapo Vienamo
2018-08-07 14:00 ` [PATCH 5/8] arm64: dts: tegra186: Add SDMMC4 DQS trim value Aapo Vienamo
2018-08-09 11:49   ` Thierry Reding
2018-08-09 12:02     ` Aapo Vienamo
2018-08-09 12:23       ` Peter Geis [this message]
2018-08-09 12:37         ` Aapo Vienamo
2018-08-09 12:50           ` Peter Geis
2018-08-09 13:52       ` Thierry Reding
2018-08-07 14:00 ` [PATCH 6/8] arm64: dts: tegra210: " Aapo Vienamo
2018-08-07 14:00 ` [PATCH 7/8] arm64: dts: tegra186: Enable HS400 Aapo Vienamo
2018-08-07 14:00 ` [PATCH 8/8] arm64: dts: tegra210: " Aapo Vienamo

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