net: axienet: Use clock framework to get device clock rate

This driver was previously always calculating the MDIO clock divisor
(from AXI bus clock to MDIO bus clock) based on the CPU clock frequency,
assuming that it is the same as the AXI bus frequency, but that
simplistic method only works on the MicroBlaze platform.

Add support for specifying the clock used for the device in the device
tree using the clock framework. If the clock is specified then it will
be used when calculating the clock divisor. The previous CPU clock
detection method is left for backward compatibility if no clock is
specified.

Signed-off-by: Robert Hancock <hancock@sedsystems.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/net/xilinx_axienet.txt b/Documentation/devicetree/bindings/net/xilinx_axienet.txt
index 38f9ec076743..2dea90332ebb 100644
--- a/Documentation/devicetree/bindings/net/xilinx_axienet.txt
+++ b/Documentation/devicetree/bindings/net/xilinx_axienet.txt
@@ -31,6 +31,11 @@ Optional properties:
 		  1 to enable partial TX checksum offload,
 		  2 to enable full TX checksum offload
 - xlnx,rxcsum	: Same values as xlnx,txcsum but for RX checksum offload
+- clocks	: AXI bus clock for the device. Refer to common clock bindings.
+		  Used to calculate MDIO clock divisor. If not specified, it is
+		  auto-detected from the CPU clock (but only on platforms where
+		  this is possible). New device trees should specify this - the
+		  auto detection is only for backward compatibility.
 
 Example:
 	axi_ethernet_eth: ethernet@40c00000 {
@@ -38,6 +43,7 @@ Example:
 		device_type = "network";
 		interrupt-parent = <&microblaze_0_axi_intc>;
 		interrupts = <2 0>;
+		clocks = <&axi_clk>;
 		phy-mode = "mii";
 		reg = <0x40c00000 0x40000>;
 		xlnx,rxcsum = <0x2>;