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authorSam Protsenko <semen.protsenko@linaro.org>2021-10-13 20:20:42 +0300
committerStephen Boyd <sboyd@kernel.org>2021-12-09 17:27:24 -0800
commita331659e32718b31f3a304d7797a77d31610468c (patch)
tree10d5a2c05220006a2c7459930948e379f6f9c612 /drivers/clk/clk.c
parentfa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf (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.c42
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,
+ &current_parent_rw_fops);
+ else
+#endif
if (core->num_parents > 0)
debugfs_create_file("clk_parent", 0444, root, core,
&current_parent_fops);