diff options
| author | Sam Protsenko <semen.protsenko@linaro.org> | 2021-10-13 20:20:42 +0300 |
|---|---|---|
| committer | Stephen Boyd <sboyd@kernel.org> | 2021-12-09 17:27:24 -0800 |
| commit | a331659e32718b31f3a304d7797a77d31610468c (patch) | |
| tree | 10d5a2c05220006a2c7459930948e379f6f9c612 /drivers/clk/clk.c | |
| parent | fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf (diff) | |
clk: Add write operation for clk_parent debugfs node
Useful for testing mux clocks. One can write the index of the parent to
be set into clk_parent node, starting from 0. Example
# cd /sys/kernel/debug/clk/mout_peri_bus
# cat clk_possible_parents
dout_shared0_div4 dout_shared1_div4
# cat clk_parent
dout_shared0_div4
# echo 1 > clk_parent
# cat clk_parent
dout_shared1_div4
CLOCK_ALLOW_WRITE_DEBUGFS has to be defined in drivers/clk/clk.c in
order to use this feature.
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Michael Turquette <mturquette@baylibre.com>
Link: https://lore.kernel.org/r/20211013172042.10884-1-semen.protsenko@linaro.org
[sboyd@kernel.org: Collapse ifdefs]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Diffstat (limited to 'drivers/clk/clk.c')
| -rw-r--r-- | drivers/clk/clk.c | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index f467d63bbf1e..8ccedec2cc9d 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -3217,6 +3217,42 @@ static int current_parent_show(struct seq_file *s, void *data) } DEFINE_SHOW_ATTRIBUTE(current_parent); +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS +static ssize_t current_parent_write(struct file *file, const char __user *ubuf, + size_t count, loff_t *ppos) +{ + struct seq_file *s = file->private_data; + struct clk_core *core = s->private; + struct clk_core *parent; + u8 idx; + int err; + + err = kstrtou8_from_user(ubuf, count, 0, &idx); + if (err < 0) + return err; + + parent = clk_core_get_parent_by_index(core, idx); + if (!parent) + return -ENOENT; + + clk_prepare_lock(); + err = clk_core_set_parent_nolock(core, parent); + clk_prepare_unlock(); + if (err) + return err; + + return count; +} + +static const struct file_operations current_parent_rw_fops = { + .open = current_parent_open, + .write = current_parent_write, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; +#endif + static int clk_duty_cycle_show(struct seq_file *s, void *data) { struct clk_core *core = s->private; @@ -3282,8 +3318,12 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry) #ifdef CLOCK_ALLOW_WRITE_DEBUGFS debugfs_create_file("clk_prepare_enable", 0644, root, core, &clk_prepare_enable_fops); -#endif + if (core->num_parents > 1) + debugfs_create_file("clk_parent", 0644, root, core, + ¤t_parent_rw_fops); + else +#endif if (core->num_parents > 0) debugfs_create_file("clk_parent", 0444, root, core, ¤t_parent_fops); |