[RFC PATCH 09/11] sdhci: dt-bindings: configuration settings

Krishna Yarlagadda
2024-05-06T22:53:21Z

SDHCI vendor tuning registers are configured using config setting
framework. Document available config for Tegra SDHCI controllers.

Signed-off-by: Krishna Yarlagadda <kyarlagadda@nvidia.com>
---
.../bindings/mmc/nvidia,tegra20-sdhci.yaml | 36 +++++++++++++++++++
1 file changed, 36 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.yaml b/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.yaml
index 72987f0326a1..002bc1ffc156 100644
--- a/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.yaml
+++ b/Documentation/devicetree/bindings/mmc/nvidia,tegra20-sdhci.yaml
@@ -177,6 +177,37 @@ properties:
operates at a 1.8 V fixed I/O voltage.
$ref: /schemas/types.yaml#/definitions/flag

+ config:
+ description: Config settings for SDHCI devices.
+ Config setting is the configuration based on chip/board/system
+ characterization on interface/controller settings. This is needed for
+ - making the controller internal configuration to better perform
+ - making the interface to work proper by setting drive strength, slew
+ rates etc
+ - making the low power leakage.
+ SDHCI has configuration based on device speed modes.
+ - common is set on all speeds and can be overridden by speed mode.
+ - List of speed modes and their config name
+ "default", /* MMC_TIMING_LEGACY */
+ "sd-mmc-highspeed", /* MMC_TIMING_MMC_HS */
+ "sd-mmc-highspeed", /* MMC_TIMING_SD_HS */
+ "uhs-sdr12", /* MMC_TIMING_UHS_SDR12 */
+ "uhs-sdr25", /* MMC_TIMING_UHS_SDR25 */
+ "uhs-sdr50", /* MMC_TIMING_UHS_SDR50 */
+ "uhs-sdr104", /* MMC_TIMING_UHS_SDR104 */
+ "uhs-ddr52", /* MMC_TIMING_UHS_DDR50 */
+ "uhs-ddr52", /* MMC_TIMING_MMC_DDR52 */
+ "mmc-hs200", /* MMC_TIMING_MMC_HS200 */
+ "mmc-hs400", /* MMC_TIMING_MMC_HS400 */
+ type: object
+ unevaluatedProperties: true
+ properties:
+ nvidia,num-tuning-iter:
+ description: Specify DQS trim value for HS400 timing.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 0
+ maximum: 0xffff
+
required:
- compatible
- reg
@@ -278,6 +309,11 @@ examples:
wp-gpios = <&gpio 57 0>; /* gpio PH1 */
power-gpios = <&gpio 155 0>; /* gpio PT3 */
bus-width = <8>;
+ config {
+ mmc-hs200 {
+ nvidia,num-tuning-iter = <0x2>;
+ };
+ };
};

- |
--
2.43.2