dt-bindings: phy: Add RX equalizer properties for Broadcom SATA PHY

Define two new properties: brcm,rx-aeq-mode which allows configuring the
SATA PHY RX equalizers and when "manual" is used, brcm,rx-aeq can be
used to set the exact value.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

Documentation/devicetree/bindings/phy/brcm-sata-phy.txt

@@ -27,7 +27,16 @@ Sub-nodes optional properties:
      This property is not applicable for "brcm,iproc-ns2-sata-phy",
      "brcm,iproc-nsp-sata-phy" and "brcm,iproc-sr-sata-phy".
 
-Example:
+- brcm,rxaeq-mode: string that indicates the desired RX equalizer
+  mode, possible values are:
+	"off" (equivalent to not specifying the property)
+	"auto"
+	"manual" (brcm,rxaeq-value is used in that case)
+
+- brcm,rxaeq-value: when 'rxaeq-mode' is set to "manual", provides the RX
+  equalizer value that should be used. Allowed range is 0..63.
+
+Example
 	sata-phy@f0458100 {
 		compatible = "brcm,bcm7445-sata-phy", "brcm,phy-sata3";
 		reg = <0xf0458100 0x1e00>, <0xf045804c 0x10>;