Re: [PATCH v2 2/3] netdev/of/phy: Add MDIO bus multiplexer support.

On 09/28/2011 10:32 AM, Michał Mirosław wrote:

W dniu 28 września 2011 18:51 użytkownik David Daney
[off-list ref]  napisał:

quoted

On 09/28/2011 12:25 AM, Michał Mirosław wrote:

quoted

2011/9/28 David Daney[off-list ref]:
[...]

quoted

+Example :
+
+       /* The parent MDIO bus. */
+       smi1: mdio@1180000001900 {
+               compatible = "cavium,octeon-3860-mdio";
+               #address-cells =<1>;
+               #size-cells =<0>;
+               reg =<0x11800 0x00001900 0x0 0x40>;
+       };
+
+       /*
+          An NXP sn74cbtlv3253 dual 1-of-4 switch controlled by a
+          pair of GPIO lines.  Child busses 2 and 3 populated with 4
+          PHYs each.
+        */
+       mdio-mux {
+               compatible = "cavium,mdio-mux-sn74cbtlv3253",
"cavium,mdio-mux";
+               gpios =<&gpio1 3 0>,<&gpio1 4 0>;
+               mdio-parent-bus =<&smi1>;
+               #address-cells =<1>;
+               #size-cells =<0>;

This should probably have 'compatible = "nxp,sn74cbtlv3253";' here.

No, the sn74cbtlv3253 is a general purpose part that could be used to
multiplex anything (I2C, SPI, random analog signals, etc.).  Only when it is
in the "cavium,mdio-mux-sn74cbtlv3253" configuration is it an MDIO bus
multiplexer.

This should use some generic name then. 'mdio-mux-gpio' or something.
There's no point in introducing chip's model for a gate-like discrete
device.

That could be.  We could define an "mdio-mux-gpio" as something that selects the child bus based on the binary encoded value presented on the GPIO lines.

I will regenerate the patch set with this in mind.  Note that the only part of this patch that will change is this mdio-mux.txt file, no actual code is affected.  In patch 3/3 I will add "mdio-mux-gpio" to the .of_match_table.

Thanks,
David Daney