From: Peter Geis <pgwipeout@gmail.com>
To: Aapo Vienamo <avienamo@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>,
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 08:50:05 -0400 [thread overview]
Message-ID: <66f8381b-7c57-d88b-6e75-e9df7843f93c@gmail.com> (raw)
In-Reply-To: <20180809153732.4c91e425@dhcp-10-21-25-168>
On 08/09/2018 08:37 AM, Aapo Vienamo wrote:
> On Thu, 9 Aug 2018 08:23:16 -0400
> Peter Geis <pgwipeout@gmail.com> wrote:
>
>> 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?
>
> I can't find any mention of _SDMMC_ DQS trimmer on Tegra2, Tegra3 or
> Tegra124 TRMs. As far as I can tell, programming the DQS trimmer value
> is only required by HS400 signaling on Tegra210 and Tegra186.
>
> -Aapo
>
Apologies, I was referring to the default Tap/Trim values.
DQS found it's way into my brain from the memory controller.
next prev parent reply other threads:[~2018-08-09 12:50 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
2018-08-09 12:37 ` Aapo Vienamo
2018-08-09 12:50 ` Peter Geis [this message]
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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