[PATCH 4/4] clk: keystone: sci-clk: add debugfs support for read/write of parent ID

[Tero Kristo <t-kristo@ti.com>]

Add parent_id node under debugfs for TI SCI clocks, that allow both
read/write operations. This can be used to read the current
parent ID, or force a change of current parent of a multi-parent clock.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
---
 drivers/clk/keystone/sci-clk.c | 45 ++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/drivers/clk/keystone/sci-clk.c b/drivers/clk/keystone/sci-clk.c
index 7edf8c8432b6..39255b13bdc1 100644
--- a/drivers/clk/keystone/sci-clk.c
+++ b/drivers/clk/keystone/sci-clk.c
@@ -24,6 +24,7 @@
 #include <linux/soc/ti/ti_sci_protocol.h>
 #include <linux/bsearch.h>
 #include <linux/list_sort.h>
+#include <linux/debugfs.h>
 
 #define SCI_CLK_SSC_ENABLE		BIT(0)
 #define SCI_CLK_ALLOW_FREQ_CHANGE	BIT(1)
@@ -254,6 +255,41 @@ static int sci_clk_set_parent(struct clk_hw *hw, u8 index)
 					      index + 1 + clk->clk_id);
 }
 
+#ifdef CONFIG_COMMON_CLK_DEBUGFS_WRITE_ACCESS
+static int dbg_pid_get(void *data, u64 *val)
+{
+	struct clk_hw *hw = data;
+
+	*val = sci_clk_get_parent(hw);
+
+	return 0;
+}
+
+static int dbg_pid_set(void *data, u64 val)
+{
+	struct clk_hw *hw = data;
+	struct clk_hw *parent = clk_hw_get_parent_by_index(hw, val);
+
+	if (!parent)
+		return -EINVAL;
+
+	clk_hw_reparent(hw, parent);
+
+	return sci_clk_set_parent(hw, val);
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(sci_parent_id_fops, dbg_pid_get, dbg_pid_set, "%llu\n");
+
+static void sci_clk_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+	debugfs_create_file("parent_id", 0644, dentry, hw, &sci_parent_id_fops);
+}
+#else
+static void sci_clk_debug_init(struct clk_hw *hw, struct dentry *dentry)
+{
+}
+#endif
+
 static const struct clk_ops sci_clk_ops = {
 	.prepare = sci_clk_prepare,
 	.unprepare = sci_clk_unprepare,
@@ -263,6 +307,7 @@ static const struct clk_ops sci_clk_ops = {
 	.set_rate = sci_clk_set_rate,
 	.get_parent = sci_clk_get_parent,
 	.set_parent = sci_clk_set_parent,
+	.debug_init = sci_clk_debug_init,
 };
 
 /**
-- 
2.17.1

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