clk: renesas: rzg2l-cpg: Refactor Runtime PM clock validation

Refactor rzg2l_cpg_attach_dev to delegate clock validation for Runtime PM
to the updated rzg2l_cpg_is_pm_clk function. Ensure validation of clocks
associated with the power domain while excluding external and core clocks.
Prevent incorrect Runtime PM management for clocks outside the domain's
scope.

Update rzg2l_cpg_is_pm_clk to operate on a per-power-domain basis. Verify
clkspec.np against the domain's device node, check argument validity, and
validate clock type (CPG_MOD). Use the no_pm_mod_clks array to exclude
specific clocks from PM management.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20241216210201.239855-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: prabhakarlad

drivers/clk/renesas/rzg2l-cpg.c

@@ -1538,28 +1538,6 @@ static int rzg2l_cpg_reset_controller_register(struct rzg2l_cpg_priv *priv)
 	return devm_reset_controller_register(priv->dev, &priv->rcdev);
 }
 
-static bool rzg2l_cpg_is_pm_clk(struct rzg2l_cpg_priv *priv,
-				const struct of_phandle_args *clkspec)
-{
-	const struct rzg2l_cpg_info *info = priv->info;
-	unsigned int id;
-	unsigned int i;
-
-	if (clkspec->args_count != 2)
-		return false;
-
-	if (clkspec->args[0] != CPG_MOD)
-		return false;
-
-	id = clkspec->args[1] + info->num_total_core_clks;
-	for (i = 0; i < info->num_no_pm_mod_clks; i++) {
-		if (info->no_pm_mod_clks[i] == id)
-			return false;
-	}
-
-	return true;
-}
-
 /**
  * struct rzg2l_cpg_pm_domains - RZ/G2L PM domains data structure
  * @onecell_data: cell data
@@ -1584,45 +1562,73 @@ struct rzg2l_cpg_pd {
 	u16 id;
 };
 
+static bool rzg2l_cpg_is_pm_clk(struct rzg2l_cpg_pd *pd,
+				const struct of_phandle_args *clkspec)
+{
+	if (clkspec->np != pd->genpd.dev.of_node || clkspec->args_count != 2)
+		return false;
+
+	switch (clkspec->args[0]) {
+	case CPG_MOD: {
+		struct rzg2l_cpg_priv *priv = pd->priv;
+		const struct rzg2l_cpg_info *info = priv->info;
+		unsigned int id = clkspec->args[1];
+
+		if (id >= priv->num_mod_clks)
+			return false;
+
+		id += info->num_total_core_clks;
+
+		for (unsigned int i = 0; i < info->num_no_pm_mod_clks; i++) {
+			if (info->no_pm_mod_clks[i] == id)
+				return false;
+		}
+
+		return true;
+	}
+
+	case CPG_CORE:
+	default:
+		return false;
+	}
+}
+
 static int rzg2l_cpg_attach_dev(struct generic_pm_domain *domain, struct device *dev)
 {
 	struct rzg2l_cpg_pd *pd = container_of(domain, struct rzg2l_cpg_pd, genpd);
-	struct rzg2l_cpg_priv *priv = pd->priv;
 	struct device_node *np = dev->of_node;
 	struct of_phandle_args clkspec;
 	bool once = true;
 	struct clk *clk;
+	unsigned int i;
 	int error;
-	int i = 0;
-
-	while (!of_parse_phandle_with_args(np, "clocks", "#clock-cells", i,
-					   &clkspec)) {
-		if (rzg2l_cpg_is_pm_clk(priv, &clkspec)) {
-			if (once) {
-				once = false;
-				error = pm_clk_create(dev);
-				if (error) {
-					of_node_put(clkspec.np);
-					goto err;
-				}
-			}
-			clk = of_clk_get_from_provider(&clkspec);
+
+	for (i = 0; !of_parse_phandle_with_args(np, "clocks", "#clock-cells", i, &clkspec); i++) {
+		if (!rzg2l_cpg_is_pm_clk(pd, &clkspec)) {
 			of_node_put(clkspec.np);
-			if (IS_ERR(clk)) {
-				error = PTR_ERR(clk);
-				goto fail_destroy;
-			}
+			continue;
+		}
 
-			error = pm_clk_add_clk(dev, clk);
+		if (once) {
+			once = false;
+			error = pm_clk_create(dev);
 			if (error) {
-				dev_err(dev, "pm_clk_add_clk failed %d\n",
-					error);
-				goto fail_put;
+				of_node_put(clkspec.np);
+				goto err;
 			}
-		} else {
-			of_node_put(clkspec.np);
 		}
-		i++;
+		clk = of_clk_get_from_provider(&clkspec);
+		of_node_put(clkspec.np);
+		if (IS_ERR(clk)) {
+			error = PTR_ERR(clk);
+			goto fail_destroy;
+		}
+
+		error = pm_clk_add_clk(dev, clk);
+		if (error) {
+			dev_err(dev, "pm_clk_add_clk failed %d\n", error);
+			goto fail_put;
+		}
 	}
 
 	return 0;