[PATCH 1/2] Documentation: phy: introduce new optional property to specify drive impedance

From: Shawn Lin <shawn.lin@rock-chips.com>
To: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	devicetree@vger.kernel.org, linux-rockchip@lists.infradead.org,
	Heiko Stuebner <heiko@sntech.de>,
	Douglas Anderson <dianders@chromium.org>,
	linux-kernel@vger.kernel.org,
	Shawn Lin <shawn.lin@rock-chips.com>
Subject: [PATCH 1/2] Documentation: phy: introduce new optional property to specify drive impedance
Date: Thu,  5 Jan 2017 17:31:21 +0800	[thread overview]
Message-ID: <1483608682-226716-1-git-send-email-shawn.lin@rock-chips.com> (raw)

We need to modify the drive impedance according to the
different hardware condition. So let's expose this to
the DT.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
---

 Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
index e3ea557..731aeb9 100644
--- a/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
+++ b/Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt
@@ -14,6 +14,11 @@ specified by name:
 		access to it), it is strongly suggested.
  - clocks: Should have a phandle to the card clock exported by the SDHCI driver.
 
+Optional Properties:
+- drive_impedance: Must be one of 33, 40, 50, 66, 100. This property allows
+	different boards to specify their own drive impedance depending on the
+	hardware condition.
+
 Example:
 
 
-- 
1.9.1
