clk: Add clk_min/max_rate entries in debugfs

Add two files to expose min/max clk rates as determined by
clk_core_get_boundaries, taking all consumer requests into account.

This information does not appear to be otherwise exposed to userspace.
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Link: https://lkml.kernel.org/r/68e96af2df96512300604d797ade2088d7e6e496.1562073871.git.leonard.crestez@nxp.com
[sboyd@kernel.org: Drop if statements for JSON printing]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/clk.c

@@ -2896,15 +2896,21 @@ DEFINE_SHOW_ATTRIBUTE(clk_summary);
 
 static void clk_dump_one(struct seq_file *s, struct clk_core *c, int level)
 {
+	unsigned long min_rate, max_rate;
+
 	if (!c)
 		return;
 
+	clk_core_get_boundaries(c, &min_rate, &max_rate);
+
 	/* This should be JSON format, i.e. elements separated with a comma */
 	seq_printf(s, "\"%s\": { ", c->name);
 	seq_printf(s, "\"enable_count\": %d,", c->enable_count);
 	seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
 	seq_printf(s, "\"protect_count\": %d,", c->protect_count);
 	seq_printf(s, "\"rate\": %lu,", clk_core_get_rate(c));
+	seq_printf(s, "\"min_rate\": %lu,", min_rate);
+	seq_printf(s, "\"max_rate\": %lu,", max_rate);
 	seq_printf(s, "\"accuracy\": %lu,", clk_core_get_accuracy(c));
 	seq_printf(s, "\"phase\": %d,", clk_core_get_phase(c));
 	seq_printf(s, "\"duty_cycle\": %u",
@@ -3064,6 +3070,34 @@ static int clk_duty_cycle_show(struct seq_file *s, void *data)
 }
 DEFINE_SHOW_ATTRIBUTE(clk_duty_cycle);
 
+static int clk_min_rate_show(struct seq_file *s, void *data)
+{
+	struct clk_core *core = s->private;
+	unsigned long min_rate, max_rate;
+
+	clk_prepare_lock();
+	clk_core_get_boundaries(core, &min_rate, &max_rate);
+	clk_prepare_unlock();
+	seq_printf(s, "%lu\n", min_rate);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(clk_min_rate);
+
+static int clk_max_rate_show(struct seq_file *s, void *data)
+{
+	struct clk_core *core = s->private;
+	unsigned long min_rate, max_rate;
+
+	clk_prepare_lock();
+	clk_core_get_boundaries(core, &min_rate, &max_rate);
+	clk_prepare_unlock();
+	seq_printf(s, "%lu\n", max_rate);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(clk_max_rate);
+
 static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
 {
 	struct dentry *root;
@@ -3075,6 +3109,8 @@ static void clk_debug_create_one(struct clk_core *core, struct dentry *pdentry)
 	core->dentry = root;
 
 	debugfs_create_ulong("clk_rate", 0444, root, &core->rate);
+	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_flags", 0444, root, core, &clk_flags_fops);