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-rw-r--r--Documentation/clk.txt11
-rw-r--r--Documentation/kernel-parameters.txt8
-rw-r--r--drivers/clk/clk.c13
3 files changed, 32 insertions, 0 deletions
diff --git a/Documentation/clk.txt b/Documentation/clk.txt
index 4274a54..b9911c2 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.
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 4609e81..9aa5562 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -44,6 +44,7 @@ parameter is applicable:
AVR32 AVR32 architecture is enabled.
AX25 Appropriate AX.25 support is enabled.
BLACKFIN Blackfin architecture is enabled.
+ CLK Common clock infrastructure is enabled.
DRM Direct Rendering Management support is enabled.
DYNAMIC_DEBUG Build in debug messages and enable them at runtime
EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
@@ -465,6 +466,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
cio_ignore= [S390]
See Documentation/s390/CommonIO for details.
+ clk_ignore_unused
+ [CLK]
+ Keep all clocks already enabled by bootloader on,
+ even if no driver has claimed them. This is useful
+ for debug and development, but should not be
+ needed on a platform with proper driver support.
+ For more information, see Documentation/clk.txt.
clock= [BUGS=X86-32, HW] gettimeofday clocksource override.
[Deprecated]
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 20ce67f..934cfd1 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -499,10 +499,23 @@ out:
return;
}
+static bool clk_ignore_unused;
+static int __init clk_ignore_unused_setup(char *__unused)
+{
+ clk_ignore_unused = true;
+ return 1;
+}
+__setup("clk_ignore_unused", clk_ignore_unused_setup);
+
static int clk_disable_unused(void)
{
struct clk *clk;
+ if (clk_ignore_unused) {
+ pr_warn("clk: Not disabling unused clocks\n");
+ return 0;
+ }
+
clk_prepare_lock();
hlist_for_each_entry(clk, &clk_root_list, child_node)
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