[PATCH] dt/bindings: update fsl-fec regarding compatible and clocks

On Mon, Feb 17, 2014 at 10:24:39PM +0100, Gerhard Sittig wrote:

On Mon, Feb 10, 2014 at 19:50 +0800, Shawn Guo wrote:

quoted

Update fsl-fec to explicitly list the supported compatible strings
and add missing 'clocks' and 'clock-names' properties.  It does not
change anything about how kernel drive works.  Instead, it just reflects
how kernel driver works today.

Signed-off-by: Shawn Guo <redacted>
---
 Documentation/devicetree/bindings/net/fsl-fec.txt |   19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/net/fsl-fec.txt b/Documentation/devicetree/bindings/net/fsl-fec.txt
index 845ff84..3ebd395 100644
--- a/Documentation/devicetree/bindings/net/fsl-fec.txt
+++ b/Documentation/devicetree/bindings/net/fsl-fec.txt

@@ -1,9 +1,26 @@
 * Freescale Fast Ethernet Controller (FEC)
 
 Required properties:
-- compatible : Should be "fsl,<soc>-fec"
+- compatible : Should contain one of the following:
+		"fsl,imx25-fec"
+		"fsl,imx27-fec"
+		"fsl,imx28-fec"
+		"fsl,imx6q-fec"
+		"fsl,mvf600-fec"

This appears to miss all the PowerPC based SoCs.  See
  git grep 'fsl,.*-fec' arch/*/boot/dts

Hmm, this is a binding for IMX FEC/ENET, and the driver is
drivers/net/ethernet/freescale/fec_main.c.  I think I've listed all the
compatibles that the driver supports.

quoted

 - reg : Address and length of the register set for the device
 - interrupts : Should contain fec interrupt
+- clocks: phandle to the clocks feeding the FEC controller and phy. The
+  following two are required:
+   - "ipg": the peripheral access clock
+   - "ahb": the bus clock for MAC
+  The following two are optional:
+   - "ptp": the sampling clock for PTP (IEEE 1588).  On SoC like i.MX6Q,
+     the clock could come from either the internal clock control module
+     or external oscillator via pad depending on board design.
+   - "enet_out": the phy reference clock provided by SoC via pad, which
+     is available on SoC like i.MX28.
+- clock-names: Must contain the clock names described just above
+

Listing 'clocks' under the "required properties" all of a sudden
invalidates existing device trees, if they don't carry the
property which before the change was not required, not even
documented.

Since the day we move to device tree clock lookup, the driver fec_main
does not probe at all if the property is absent.

The PowerPC based chips probably have differing sets of clocks.
I'm aware of the MPC512x, where one "per" clock is sufficient,
and even this spec is optional.  Other machines may not have yet
been converted to CCF.

Again, the binding is created for IMX FEC/ENET controller and the driver
fec_main, so I'm not sure you should look at this binding for
PowerPC/MPC512x stuff at all.

Your description needs to get rephrased, it triggers Mark
Rutland's regular "clocks are not just phandles" reply.  See how
he suggested quite a few times a better wording.

Can you give a pointer or good example?  I worded it following an
example [1] found on recent linux-next/spi tree. 

Shawn

[1] https://git.kernel.org/cgit/linux/kernel/git/broonie/spi.git/commit/?h=topic/sunxi&id=3558fe900e8af6c3bfadeff24a12ffb19ac9b108