clk: scmi: Add support for rate change restricted clocks

Some exposed SCMI Clocks could be marked as non-supporting rate changes.
Configure a clk_ops descriptors which does not provide the rate change
callbacks for such clocks when registering with CLK framework.

CC: Michael Turquette <[email protected]>
CC: Stephen Boyd <[email protected]>
CC: [email protected]
Signed-off-by: Cristian Marussi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Sudeep Holla <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>

Author: cris-ma

drivers/clk/clk-scmi.c

@@ -20,6 +20,7 @@
 enum scmi_clk_feats {
 	SCMI_CLK_ATOMIC_SUPPORTED,
 	SCMI_CLK_STATE_CTRL_SUPPORTED,
+	SCMI_CLK_RATE_CTRL_SUPPORTED,
 	SCMI_CLK_FEATS_COUNT
 };
 
@@ -248,7 +249,8 @@ scmi_clk_ops_alloc(struct device *dev, unsigned long feats_key)
 	ops->recalc_rate = scmi_clk_recalc_rate;
 	ops->round_rate = scmi_clk_round_rate;
 	ops->determine_rate = scmi_clk_determine_rate;
-	ops->set_rate = scmi_clk_set_rate;
+	if (feats_key & BIT(SCMI_CLK_RATE_CTRL_SUPPORTED))
+		ops->set_rate = scmi_clk_set_rate;
 
 	/* Parent ops */
 	ops->get_parent = scmi_clk_get_parent;
@@ -302,6 +304,9 @@ scmi_clk_ops_select(struct scmi_clk *sclk, bool atomic_capable,
 	if (!ci->state_ctrl_forbidden)
 		feats_key |= BIT(SCMI_CLK_STATE_CTRL_SUPPORTED);
 
+	if (!ci->rate_ctrl_forbidden)
+		feats_key |= BIT(SCMI_CLK_RATE_CTRL_SUPPORTED);
+
 	if (WARN_ON(feats_key >= db_size))
 		return NULL;