clk: Add support for enabling/disabling clocks from debugfs (03111b10) · Commits · 戴 / test

For test and debug purposes, it's simple enough 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_DEBUGFS. Signed-off-by:

Mike Tipton <mdtipton@codeaurora.org> Link: https://lore.kernel.org/r/20200630003024.6282-1-mdtipton@codeaurora.org [sboyd@kernel.org: Reword commit text and remove comment update] Signed-off-by:

Stephen Boyd <sboyd@kernel.org>

drivers/clk/clk.c

+29 −0

Original line number	Diff line number	Diff line
		@@ -3039,6 +3039,31 @@ 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
		@@ -3216,6 +3241,10 @@ 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,

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