[PATCH v2 06/11] Documentation: mmc: sdhci-of-arasan: Add ability to export card clock
From: Douglas Anderson <hidden>
Date: 2016-06-13 23:09:33
Also in:
linux-mmc, linux-rockchip, lkml
Subsystem:
multimedia card (mmc), secure digital (sd) and sdio subsystem, open firmware and flattened device tree bindings, the rest · Maintainers:
Ulf Hansson, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
Some SD/eMMC PHYs (like the PHY from Arasan that is designed to work with arasan,sdhci-5.1) need to know the card clock frequency in order to function properly. Physically in a SoC this clock is exported from the SDHCI IP block to the PHY IP block and the PHY needs to know the speed. Let's export the SDHCI card clock using a standard device tree mechanism so that the PHY can get access to it and query the card clock frequency. Signed-off-by: Douglas Anderson <redacted> Acked-by: Rob Herring <redacted> --- Changes in v2: - Adjust commit message wording (Rob) - Add Rob Herring's Ack. Documentation/devicetree/bindings/mmc/arasan,sdhci.txt | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt b/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt
index 476604e6ce2a..3404afa9b938 100644
--- a/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt
+++ b/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt@@ -30,6 +30,12 @@ Optional Properties: - arasan,soc-ctl-syscon: A phandle to a syscon device (see ../mfd/syscon.txt) used to access core corecfg registers. Offsets of registers in this syscon are determined based on the main compatible string for the device. + - clock-output-names: If specified, this will be the name of the card clock + which will be exposed by this device. Required if #clock-cells is + specified. + - #clock-cells: If specified this should be the value <0>. With this property + in place we will export a clock representing the Card Clock. This clock + is expected to be consumed by our PHY. You must also specify Example: sdhci@e0100000 {
@@ -61,7 +67,9 @@ Example: arasan,soc-ctl-syscon = <&grf>; assigned-clocks = <&cru SCLK_EMMC>; assigned-clock-rates = <200000000>; + clock-output-names = "emmc_cardclock"; phys = <&emmc_phy>; phy-names = "phy_arasan"; + #clock-cells = <0>; status = "disabled"; };
--
2.8.0.rc3.226.g39d4020