From 04c2facad8fee66c981a51852806d8923336f362 Mon Sep 17 00:00:00 2001 From: Andrew Lunn Date: Tue, 4 Feb 2014 18:33:11 +0100 Subject: drivers: phy: Make NULL a valid phy reference The common clock framework considers NULL a valid clock reference. This makes handling optional clocks simple, in that if the optional clock is not available, a NULL reference can be used in the place of a real clock, simplifying the clock consumer. Extend this concept to the phy consumer API. A NULL can be passed to the release calls, the phy_init() and phy_exit() calls, and phy_power_on() and phy_power_off() and a NOP is performed. Signed-off-by: Andrew Lunn Tested-by: Gregory CLEMENT Acked-by: Kishon Vijay Abraham I Signed-off-by: Jason Cooper --- Documentation/phy.txt | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'Documentation/phy.txt') diff --git a/Documentation/phy.txt b/Documentation/phy.txt index 0103e4b15b0e..2e24b993e95f 100644 --- a/Documentation/phy.txt +++ b/Documentation/phy.txt @@ -84,6 +84,12 @@ The only difference between the two APIs is that devm_phy_get associates the device with the PHY using devres on successful PHY get. On driver detach, release function is invoked on the the devres data and devres data is freed. +It should be noted that NULL is a valid phy reference. All phy +consumer calls on the NULL phy become NOPs. That is the release calls, +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. + 5. Releasing a reference to the PHY When the controller no longer needs the PHY, it has to release the reference -- cgit v1.2.3