clk: scmi: add the command CLOCK_PARENT_SET

This patch adds the command CLOCK_PARENT_SET that can be used to set the
parent of a clock. ARM SCMI Version 3.2 supports to change the parent of
a clock device.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Alice Guo <alice.guo@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Marek Vasut <marex@denx.de>

drivers/clk/clk_scmi.c

@@ -179,11 +179,31 @@ static int scmi_clk_probe(struct udevice *dev)
 	return 0;
 }
 
+static int scmi_clk_set_parent(struct clk *clk, struct clk *parent)
+{
+	struct scmi_clk_parent_set_in in = {
+		.clock_id = clk->id,
+		.parent_clk = parent->id,
+	};
+	struct scmi_clk_parent_set_out out;
+	struct scmi_msg msg = SCMI_MSG_IN(SCMI_PROTOCOL_ID_CLOCK,
+					  SCMI_CLOCK_PARENT_SET,
+					  in, out);
+	int ret;
+
+	ret = devm_scmi_process_msg(clk->dev, &msg);
+	if (ret < 0)
+		return ret;
+
+	return scmi_to_linux_errno(out.status);
+}
+
 static const struct clk_ops scmi_clk_ops = {
 	.enable = scmi_clk_enable,
 	.disable = scmi_clk_disable,
 	.get_rate = scmi_clk_get_rate,
 	.set_rate = scmi_clk_set_rate,
+	.set_parent = scmi_clk_set_parent,
 };
 
 U_BOOT_DRIVER(scmi_clock) = {

include/scmi_protocols.h

@@ -737,6 +737,7 @@ enum scmi_clock_message_id {
 	SCMI_CLOCK_RATE_SET = 0x5,
 	SCMI_CLOCK_RATE_GET = 0x6,
 	SCMI_CLOCK_CONFIG_SET = 0x7,
+	SCMI_CLOCK_PARENT_SET = 0xD,
 };
 
 #define SCMI_CLK_PROTO_ATTR_COUNT_MASK	GENMASK(15, 0)
@@ -839,6 +840,24 @@ struct scmi_clk_rate_set_out {
 	s32 status;
 };
 
+/**
+ * struct scmi_clk_parent_state_in - Message payload for CLOCK_PARENT_SET command
+ * @clock_id:		SCMI clock ID
+ * @parent_clk:		SCMI clock ID
+ */
+struct scmi_clk_parent_set_in {
+	u32 clock_id;
+	u32 parent_clk;
+};
+
+/**
+ * struct scmi_clk_parent_set_out - Response payload for CLOCK_PARENT_SET command
+ * @status:	SCMI command status
+ */
+struct scmi_clk_parent_set_out {
+	s32 status;
+};
+
 /*
  * SCMI Reset Domain Protocol
  */