[PATCH 09/14] clk: mux: Support CLK_MUX_READ_ONLY flag

[Sascha Hauer <s.hauer@pengutronix.de>]

Support readonly dividers using the CLK_MUX_READ_ONLY flag.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/clk/clk-mux.c | 7 +++++++
 include/linux/clk.h   | 1 +
 2 files changed, 8 insertions(+)

diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c
index ebf736bdff..e9cb614005 100644
--- a/drivers/clk/clk-mux.c
+++ b/drivers/clk/clk-mux.c
@@ -33,6 +33,13 @@ static int clk_mux_set_parent(struct clk *clk, u8 idx)
 	struct clk_mux *m = container_of(clk, struct clk_mux, clk);
 	u32 val;
 
+	if (m->flags & CLK_MUX_READ_ONLY) {
+		if (clk_mux_get_parent(clk) != idx)
+			return -EPERM;
+		else
+			return 0;
+	}
+
 	val = readl(m->reg);
 	val &= ~(((1 << m->width) - 1) << m->shift);
 	val |= idx << m->shift;
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 2e698e2ea6..2492608a15 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -344,6 +344,7 @@ struct clk_divider {
 #define CLK_DIVIDER_READ_ONLY		(1 << 5)
 
 #define CLK_MUX_HIWORD_MASK		(1 << 2)
+#define CLK_MUX_READ_ONLY		(1 << 3) /* mux can't be changed */
 
 extern struct clk_ops clk_divider_ops;
 
-- 
2.20.1


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