Commit e43d3191 authored by John Keeping's avatar John Keeping Committed by Stephen Boyd
Browse files

clk: Allow phase adjustment from debugfs 



For testing it may be useful to manually adjust a clock's phase.  Add
support for writing to the existing clk_phase debugfs file, with the
written value clamped to [0, 360) to match the behaviour of the
clk_set_phase() function.

This is a dangerous feature, so use the existing define
CLOCK_ALLOW_WRITE_DEBUGFS to allow it only if the source is modified.

Signed-off-by: default avatarJohn Keeping <john@metanate.com>
Link: https://lore.kernel.org/r/20230420103805.125246-1-john@metanate.com


Signed-off-by: default avatarStephen Boyd <sboyd@kernel.org>
parent dcce5cc7

drivers/clk/clk.c

+30 −1
Original line number Diff line number Diff line
@@ -3343,6 +3343,21 @@ static int clk_rate_set(void *data, u64 val) 


#define clk_rate_mode	0644



static int clk_phase_set(void *data, u64 val)

{

	struct clk_core *core = data;

	int degrees = do_div(val, 360);

	int ret;



	clk_prepare_lock();

	ret = clk_core_set_phase_nolock(core, degrees);

	clk_prepare_unlock();



	return ret;

}



#define clk_phase_mode	0644



static int clk_prepare_enable_set(void *data, u64 val)

{

	struct clk_core *core = data;
@@ -3370,6 +3385,9 @@ DEFINE_DEBUGFS_ATTRIBUTE(clk_prepare_enable_fops, clk_prepare_enable_get, 
#else

#define clk_rate_set	NULL

#define clk_rate_mode	0444



#define clk_phase_set	NULL

#define clk_phase_mode	0644

#endif



static int clk_rate_get(void *data, u64 *val)
@@ -3385,6 +3403,16 @@ static int clk_rate_get(void *data, u64 *val) 


DEFINE_DEBUGFS_ATTRIBUTE(clk_rate_fops, clk_rate_get, clk_rate_set, "%llu\n");



static int clk_phase_get(void *data, u64 *val)

{

	struct clk_core *core = data;



	*val = core->phase;

	return 0;

}



DEFINE_DEBUGFS_ATTRIBUTE(clk_phase_fops, clk_phase_get, clk_phase_set, "%llu\n");



static const struct {

	unsigned long flag;

	const char *name;
@@ -3575,7 +3603,8 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry) 
	debugfs_create_file("clk_min_rate", 0444, root, core, &clk_min_rate_fops);

	debugfs_create_file("clk_max_rate", 0444, root, core, &clk_max_rate_fops);

	debugfs_create_ulong("clk_accuracy", 0444, root, &core->accuracy);

	debugfs_create_u32("clk_phase", 0444, root, &core->phase);

	debugfs_create_file("clk_phase", clk_phase_mode, root, core,

			    &clk_phase_fops);

	debugfs_create_file("clk_flags", 0444, root, core, &clk_flags_fops);

	debugfs_create_u32("clk_prepare_count", 0444, root, &core->prepare_count);

	debugfs_create_u32("clk_enable_count", 0444, root, &core->enable_count);