[PATCH v3 2/4] dt-bindings: phy: Add a new property drive-impedance-ohm for RK's emmc PHY

Christoph Muellner
2019-03-22T11:34:51Z

This patch documents the new proprty drive-impedance-ohm for
Rockchip's eMMC PHY node.

Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
---
Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
index e3ea55763b0a..e728786f21e0 100644
--- a/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
+++ b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
@@ -7,12 +7,15 @@ 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:
+Optional properties:
- 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.
+ See ../clock/clock-bindings.txt for details.
- clocks: Should have a phandle to the card clock exported by the SDHCI driver.
+ - drive-impedance-ohm: Specifies the drive impedance in Ohm.
+ Possible values are 33, 40, 50, 66 and 100.
+ If not set, the default value of 50 will be applied.

Example:

@@ -29,6 +32,7 @@ grf: syscon@ff770000 {
reg = <0xf780 0x20>;
clocks = <&sdhci>;
clock-names = "emmcclk";
+ drive-impedance-ohm = <50>;
#phy-cells = <0>;
};
};
--
2.11.0