clk: add clk_ignore_unused option to keep boot clocks on

This is primarily useful when there's a driver that doesn't claim clocks
properly, but the bootloader leaves them on. It's not expected to be used
in normal cases, but for bringup and debug it's very useful to have the
option to not gate unclaimed clocks that are still on.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
[mturquette@linaro.org: fixed up trivial merge issue]

1 files changed, 11 insertions, 0 deletions

diff --git a/Documentation/clk.txt b/Documentation/clk.txt
index 4274a546eb5..b9911c27f49 100644
--- a/Documentation/clk.txt
+++ b/Documentation/clk.txt
@@ -231,3 +231,14 @@ To better enforce this policy, always follow this simple rule: any
 statically initialized clock data MUST be defined in a separate file
 from the logic that implements its ops.  Basically separate the logic
 from the data and all is well.
+
+	Part 6 - Disabling clock gating of unused clocks
+
+Sometimes during development it can be useful to be able to bypass the
+default disabling of unused clocks. For example, if drivers aren't enabling
+clocks properly but rely on them being on from the bootloader, bypassing
+the disabling means that the driver will remain functional while the issues
+are sorted out.
+
+To bypass this disabling, include "clk_ignore_unused" in the bootargs to the
+kernel.