diff options
| -rw-r--r-- | Documentation/clk.txt | 11 | ||||
| -rw-r--r-- | Documentation/kernel-parameters.txt | 8 | ||||
| -rw-r--r-- | drivers/clk/clk.c | 13 |
3 files changed, 32 insertions, 0 deletions
diff --git a/Documentation/clk.txt b/Documentation/clk.txt index 4274a546eb57..b9911c27f496 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 4609e81dbc37..9aa5562fed9c 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 20ce67f82d65..934cfd18f72d 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) |