From 110754563c52b9cf375d48cfbe93cc1a5e92d530 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Mon, 20 Jun 2016 10:56:51 -0700 Subject: Documentation: phy: Let the rockchip eMMC PHY get an exported card clock As of an earlier change in this series ("Documentation: mmc: sdhci-of-arasan: Add ability to export card clock") the SDHCI driver used on Rockchip SoCs can now expose its clock. Let's now specify that the PHY can use it. Letting the PHY get access to this clock means it can adjust phyctrl_frqsel field appropriately. Although the Rockchip PHY appears slightly different than the reference Arasan one, you can see that the Arasan datasheet [1] had it defined as: Select the frequency range of DLL operation: 3b'000 => 200MHz to 170 MHz 3b'001 => 170MHz to 140 MHz 3b'010 => 140MHz to 110 MHz 3b'011 => 110MHz to 80MHz 3b'100 => 80MHz to 50 MHz 3b'101 => 275Mhz to 250MHz 3b'110 => 250MHz to 225MHz 3b'111 => 225MHz to 200MHz On the Rockchip version of the PHY we have less granularity but the idea is the same. [1]: https://arasan.com/wp-content/media/eMMC-5-1-Total-Solution_Rev-1-3.pdf Signed-off-by: Douglas Anderson Acked-by: Kishon Vijay Abraham I Acked-by: Rob Herring Reviewed-by: Heiko Stuebner Signed-off-by: Ulf Hansson --- Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'Documentation/devicetree/bindings/phy') diff --git a/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt index 555cb0f40690..e3ea55763b0a 100644 --- a/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt +++ b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt @@ -7,6 +7,13 @@ Required properties: - reg: PHY register address offset and length in "general register files" +Optional clocks using the clock bindings (see ../clock/clock-bindings.txt), +specified by name: + - clock-names: Should contain "emmcclk". Although this is listed as optional + (because most boards can get basic functionality without having + access to it), it is strongly suggested. + - clocks: Should have a phandle to the card clock exported by the SDHCI driver. + Example: @@ -20,6 +27,8 @@ grf: syscon@ff770000 { emmcphy: phy@f780 { compatible = "rockchip,rk3399-emmc-phy"; reg = <0xf780 0x20>; + clocks = <&sdhci>; + clock-names = "emmcclk"; #phy-cells = <0>; }; }; -- cgit v1.2.3