clk: add clk_possible_parents debugfs file

For validation purposes, it's often useful to be able to retrieve the list
of possible parents in userspace. Add a debugfs file for every clock which
has more than 1 possible parent.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Reviewed-by: Jon Mayo <jmayo@nvidia.com>
[sboyd@codeaurora.org: Remove useless cast from void and extra
newline]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 67201f6..0d8eb5a 100644 (file)
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2126,6 +2126,31 @@ static const struct file_operations clk_dump_fops = {
        .release        = single_release,
 };
 
+static int possible_parents_dump(struct seq_file *s, void *data)
+{
+       struct clk_core *core = s->private;
+       int i;
+
+       for (i = 0; i < core->num_parents - 1; i++)
+               seq_printf(s, "%s ", core->parent_names[i]);
+
+       seq_printf(s, "%s\n", core->parent_names[i]);
+
+       return 0;
+}
+
+static int possible_parents_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, possible_parents_dump, inode->i_private);
+}
+
+static const struct file_operations possible_parents_fops = {
+       .open           = possible_parents_open,
+       .read           = seq_read,
+       .llseek         = seq_lseek,
+       .release        = single_release,
+};
+
 static int clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
 {
        struct dentry *d;
@@ -2177,6 +2202,13 @@ static int clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
        if (!d)
                goto err_out;
 
+       if (core->num_parents > 1) {
+               d = debugfs_create_file("clk_possible_parents", S_IRUGO,
+                               core->dentry, core, &possible_parents_fops);
+               if (!d)
+                       goto err_out;
+       }
+
        if (core->ops->debug_init) {
                ret = core->ops->debug_init(core->hw, core->dentry);
                if (ret)