drivers/net/phy: add fixed-phy / fixed-link support

This patch adds support for having a "fixed-link" to some other MAC
(like some embedded switch-device).

For this purpose we introduce a new phy-driver, called "Fixed PHY".

Fixed PHY works only with CONFIG_DM_ETH enabled, since the fixed-link is
described with a subnode below ethernet interface.

Most ethernet drivers (unfortunately not all are following same scheme
for searching/attaching phys) are calling "phy_connect(...)" for getting
a phy-device.
At this point we link in, we search here for a subnode called "fixed-
link", once found we start phy_device_create(...) with the special phy-
id PHY_FIXED_ID (0xa5a55a5a).

During init the "Fixed PHY" driver has registered with this id and now
gets probed, during probe we get all the details about fixed-link out of
dts, later on the phy reports this values.

Signed-off-by: Hannes Schmelzer <hannes.schmelzer@br-automation.com>

Signed-off-by: Hannes Schmelzer <oe5hpm@oevsv.at>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/net/fixed-link.txt b/doc/device-tree-bindings/net/fixed-link.txt
new file mode 100644
index 0000000..5829bd8
--- /dev/null
+++ b/doc/device-tree-bindings/net/fixed-link.txt
@@ -0,0 +1,30 @@
+Fixed link Device Tree binding
+------------------------------
+
+Some Ethernet MACs have a "fixed link", and are not connected to a
+normal MDIO-managed PHY device. For those situations, a Device Tree
+binding allows to describe a "fixed link".
+
+Such a fixed link situation is described by creating a 'fixed-link'
+sub-node of the Ethernet MAC device node, with the following
+properties:
+
+* 'speed' (integer, mandatory), to indicate the link speed. Accepted
+  values are 10, 100 and 1000
+* 'full-duplex' (boolean, optional), to indicate that full duplex is
+  used. When absent, half duplex is assumed.
+* 'pause' (boolean, optional), to indicate that pause should be
+  enabled.
+* 'asym-pause' (boolean, optional), to indicate that asym_pause should
+  be enabled.
+
+Examples:
+
+ethernet@0 {
+	...
+	fixed-link {
+	      speed = <1000>;
+	      full-duplex;
+	};
+	...
+};