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author | Andrew Lunn <andrew@lunn.ch> | 2014-02-04 18:33:11 +0100 |
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committer | Jason Cooper <jason@lakedaemon.net> | 2014-02-05 05:27:54 +0000 |
commit | 04c2facad8fee66c981a51852806d8923336f362 (patch) | |
tree | 89bda05db2d208a151ed216bc4099d3371c7e6a2 /Documentation | |
parent | 38dbfb59d1175ef458d006556061adeaa8751b72 (diff) | |
download | op-kernel-dev-04c2facad8fee66c981a51852806d8923336f362.zip op-kernel-dev-04c2facad8fee66c981a51852806d8923336f362.tar.gz |
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 <andrew@lunn.ch>
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/phy.txt | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/phy.txt b/Documentation/phy.txt index 0103e4b..2e24b99 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 |