clk: propagate parent change up one level

This patch adds support for propagation of setup of clock's parent one level
up.

This feature is helpful when a driver changes topology of its clocks using
clk_set_parent().  The problem occurs when on one platform/SoC driver's clock
is located at MUX output but on the other platform/SoC there is a gated proxy
clock between the MUX and driver's clock.  In such a case, driver's code has to
be modified to use one clock for enabling and the other clock for setup of a
parent.

The code updates are avoided by propagating setup of a parent up one level.

Additionally, this patch adds CLK_SET_PARENT_PARENT (sorry for naming) flag to
inform clk-core that clk_set_parent() should be propagated.

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Change-Id: I206d23fb86cc09bce943ef9971a710876e3a7744

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 11860985fec..061052fa76e 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -27,6 +27,7 @@
 #define CLK_IS_ROOT		BIT(4) /* root clk, has no parent */
 #define CLK_IS_BASIC		BIT(5) /* Basic clk, can't do a to_clk_foo() */
 #define CLK_GET_RATE_NOCACHE	BIT(6) /* do not use the cached clk rate */
+#define CLK_SET_PARENT_PARENT	BIT(7) /* propagate parent change up one level */
 
 struct clk_hw;