clk: scmi: Add support for clock {set,get}_parent

SCMI v3.2 adds set/get parent clock commands, so update the SCMI clock
driver to support them.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20231004-scmi-clock-v3-v5-2-1b8a1435673e@nxp.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/clk/clk-scmi.c

@@ -24,6 +24,7 @@ struct scmi_clk {
 	struct clk_hw hw;
 	const struct scmi_clock_info *info;
 	const struct scmi_protocol_handle *ph;
+	struct clk_parent_data *parent_data;
 };
 
 #define to_scmi_clk(clk) container_of(clk, struct scmi_clk, hw)
@@ -78,6 +79,43 @@ static int scmi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 	return scmi_proto_clk_ops->rate_set(clk->ph, clk->id, rate);
 }
 
+static int scmi_clk_set_parent(struct clk_hw *hw, u8 parent_index)
+{
+	struct scmi_clk *clk = to_scmi_clk(hw);
+
+	return scmi_proto_clk_ops->parent_set(clk->ph, clk->id, parent_index);
+}
+
+static u8 scmi_clk_get_parent(struct clk_hw *hw)
+{
+	struct scmi_clk *clk = to_scmi_clk(hw);
+	u32 parent_id, p_idx;
+	int ret;
+
+	ret = scmi_proto_clk_ops->parent_get(clk->ph, clk->id, &parent_id);
+	if (ret)
+		return 0;
+
+	for (p_idx = 0; p_idx < clk->info->num_parents; p_idx++) {
+		if (clk->parent_data[p_idx].index == parent_id)
+			break;
+	}
+
+	if (p_idx == clk->info->num_parents)
+		return 0;
+
+	return p_idx;
+}
+
+static int scmi_clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
+{
+	/*
+	 * Suppose all the requested rates are supported, and let firmware
+	 * to handle the left work.
+	 */
+	return 0;
+}
+
 static int scmi_clk_enable(struct clk_hw *hw)
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);
@@ -139,6 +177,9 @@ static const struct clk_ops scmi_clk_ops = {
 	.set_rate = scmi_clk_set_rate,
 	.prepare = scmi_clk_enable,
 	.unprepare = scmi_clk_disable,
+	.set_parent = scmi_clk_set_parent,
+	.get_parent = scmi_clk_get_parent,
+	.determine_rate = scmi_clk_determine_rate,
 };
 
 static const struct clk_ops scmi_atomic_clk_ops = {
@@ -148,6 +189,9 @@ static const struct clk_ops scmi_atomic_clk_ops = {
 	.enable = scmi_clk_atomic_enable,
 	.disable = scmi_clk_atomic_disable,
 	.is_enabled = scmi_clk_atomic_is_enabled,
+	.set_parent = scmi_clk_set_parent,
+	.get_parent = scmi_clk_get_parent,
+	.determine_rate = scmi_clk_determine_rate,
 };
 
 static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk,
@@ -158,9 +202,10 @@ static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk,
 
 	struct clk_init_data init = {
 		.flags = CLK_GET_RATE_NOCACHE,
-		.num_parents = 0,
+		.num_parents = sclk->info->num_parents,
 		.ops = scmi_ops,
 		.name = sclk->info->name,
+		.parent_data = sclk->parent_data,
 	};
 
 	sclk->hw.init = &init;
@@ -251,9 +296,23 @@ static int scmi_clocks_probe(struct scmi_device *sdev)
 		else
 			scmi_ops = &scmi_clk_ops;
 
+		/* Initialize clock parent data. */
+		if (sclk->info->num_parents > 0) {
+			sclk->parent_data = devm_kcalloc(dev, sclk->info->num_parents,
+							 sizeof(*sclk->parent_data), GFP_KERNEL);
+			if (!sclk->parent_data)
+				return -ENOMEM;
+
+			for (int i = 0; i < sclk->info->num_parents; i++) {
+				sclk->parent_data[i].index = sclk->info->parents[i];
+				sclk->parent_data[i].hw = hws[sclk->info->parents[i]];
+			}
+		}
+
 		err = scmi_clk_ops_init(dev, sclk, scmi_ops);
 		if (err) {
 			dev_err(dev, "failed to register clock %d\n", idx);
+			devm_kfree(dev, sclk->parent_data);
 			devm_kfree(dev, sclk);
 			hws[idx] = NULL;
 		} else {