clk: Introduce clk_has_parent()

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This new function is similar to clk_set_parent(), except that it doesn't
actually change the parent. It merely checks that the given parent clock
can be a parent for the given clock.

A situation where this is useful is to check that a particular setup is
valid before switching to it. One specific use-case for this is atomic
modesetting in the DRM framework where setting a mode is divided into a
check phase where a given configuration is validated before applying
changes to the hardware.

Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>

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Thierry Reding 2015-01-21 17:13:00 +01:00 • committed by Michael Turquette

parent 97bf6af1f9

commit 4e88f3de89

2 changed files with 47 additions and 0 deletions

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30

drivers/clk/clk.c

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17

include/linux/clk.h

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