On 08/09/2018 08:02 AM, Aapo Vienamo wrote:

On Thu, 9 Aug 2018 13:49:22 +0200
Thierry Reding [off-list ref] wrote:

quoted

On Tue, Aug 07, 2018 at 05:00:01PM +0300, Aapo Vienamo wrote:

quoted

Add the HS400 DQS trim value for Tegra186 SDMMC4.

Signed-off-by: Aapo Vienamo <redacted>
---
  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?