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-rw-r--r--Documentation/driver-api/phy/phy.rst25
1 files changed, 24 insertions, 1 deletions
diff --git a/Documentation/driver-api/phy/phy.rst b/Documentation/driver-api/phy/phy.rst
index 8fc1ce0bb905..8e8b3e8f9523 100644
--- a/Documentation/driver-api/phy/phy.rst
+++ b/Documentation/driver-api/phy/phy.rst
@@ -94,7 +94,8 @@ Inorder to dereference the private data (in phy_ops), the phy provider driver
can use phy_set_drvdata() after creating the PHY and use phy_get_drvdata() in
phy_ops to get back the private data.
-4. Getting a reference to the PHY
+Getting a reference to the PHY
+==============================
Before the controller can make use of the PHY, it has to get a reference to
it. This framework provides the following APIs to get a reference to the PHY.
@@ -130,6 +131,28 @@ the phy_init() and phy_exit() calls, and phy_power_on() and
phy_power_off() calls are all NOP when applied to a NULL phy. The NULL
phy is useful in devices for handling optional phy devices.
+Order of API calls
+==================
+
+The general order of calls should be::
+
+ [devm_][of_]phy_get()
+ phy_init()
+ phy_power_on()
+ [phy_set_mode[_ext]()]
+ ...
+ phy_power_off()
+ phy_exit()
+ [[of_]phy_put()]
+
+Some PHY drivers may not implement :c:func:`phy_init` or :c:func:`phy_power_on`,
+but controllers should always call these functions to be compatible with other
+PHYs. Some PHYs may require :c:func:`phy_set_mode <phy_set_mode_ext>`, while
+others may use a default mode (typically configured via devicetree or other
+firmware). For compatibility, you should always call this function if you know
+what mode you will be using. Generally, this function should be called after
+:c:func:`phy_power_on`, although some PHY drivers may allow it at any time.
+
Releasing a reference to the PHY
================================