Document the Tegra SDHCI inbound and outbound sampling trimmer values.
Signed-off-by: Aapo Vienamo <avienamo@xxxxxxxxxx>
Acked-by: Thierry Reding <treding@xxxxxxxxxx>
---
.../devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt b/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt
index 9713e052f736..edecf97231b9 100644
--- a/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt
+++ b/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.txt
@@ -67,6 +67,10 @@ Optional properties for Tegra210 and Tegra186:
- nvidia,pad-autocal-pull-up-offset-hs400,
nvidia,pad-autocal-pull-down-offset-hs400 : Specify drive strength
calibration offsets for HS400 mode.
+- nvidia,default-tap : Specify the default inbound sampling clock
+ trimmer value for non-tunable modes.
+- nvidia,default-trim : Specify the default outbound clock trimmer
+ value.
Notes on the pad calibration pull up and pulldown offset values:
- The property values are drive codes which are programmed into the
@@ -77,6 +81,13 @@ Optional properties for Tegra210 and Tegra186:
- The SDR104 and HS400 timing specific values are used in
corresponding modes if specified.
+ Notes on tap and trim values:
+ - The values are used for compensating trace length differences
+ by adjusting the sampling point.
+ - The values are programmed to the Vendor Clock Control Register.
+ Please refer to the reference manual of the SoC for correct
+ values.
+
Example:
sdhci@700b0000 {
compatible = "nvidia,tegra210-sdhci", "nvidia,tegra124-sdhci";
--
2.18.0
