Messages in this thread Patch in this message | | | From | Mike Tipton <> | Subject | [PATCH] clk: Add support for enabling/disabling clocks from debugfs | Date | Mon, 29 Jun 2020 17:30:24 -0700 |
| |
For test and debug purposes, it's often necessary to enable or disable clocks from shell. Add a new debugfs file (clk_prepare_enable) that calls clk_prepare_enable() when writing "1" and clk_disable_unprepare() when writing "0".
This can have security implications, so only support it when the code has been modified to #define CLOCK_ALLOW_WRITE_DEBUGS.
Signed-off-by: Mike Tipton <mdtipton@codeaurora.org> --- drivers/clk/clk.c | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 236923b25543..3640bbc56870 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -3034,13 +3034,14 @@ static int clk_dump_show(struct seq_file *s, void *data) } DEFINE_SHOW_ATTRIBUTE(clk_dump); -#undef CLOCK_ALLOW_WRITE_DEBUGFS -#ifdef CLOCK_ALLOW_WRITE_DEBUGFS /* - * This can be dangerous, therefore don't provide any real compile time - * configuration option for this feature. + * These features can be dangerous, therefore don't provide any real compile + * time configuration option for them. * People who want to use this will need to modify the source code directly. */ +#undef CLOCK_ALLOW_WRITE_DEBUGFS +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS + static int clk_rate_set(void *data, u64 val) { struct clk_core *core = data; @@ -3054,6 +3055,31 @@ static int clk_rate_set(void *data, u64 val) } #define clk_rate_mode 0644 + +static int clk_prepare_enable_set(void *data, u64 val) +{ + struct clk_core *core = data; + int ret = 0; + + if (val) + ret = clk_prepare_enable(core->hw->clk); + else + clk_disable_unprepare(core->hw->clk); + + return ret; +} + +static int clk_prepare_enable_get(void *data, u64 *val) +{ + struct clk_core *core = data; + + *val = core->enable_count && core->prepare_count; + return 0; +} + +DEFINE_DEBUGFS_ATTRIBUTE(clk_prepare_enable_fops, clk_prepare_enable_get, + clk_prepare_enable_set, "%llu\n"); + #else #define clk_rate_set NULL #define clk_rate_mode 0444 @@ -3231,6 +3257,10 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry) debugfs_create_u32("clk_notifier_count", 0444, root, &core->notifier_count); debugfs_create_file("clk_duty_cycle", 0444, root, core, &clk_duty_cycle_fops); +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS + debugfs_create_file("clk_prepare_enable", 0644, root, core, + &clk_prepare_enable_fops); +#endif if (core->num_parents > 0) debugfs_create_file("clk_parent", 0444, root, core, -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
| |