clk: renesas: rzg2l: Don't assume all CPG_MOD clocks support PM

There are cases where not all CPG_MOD clocks should be assumed to support
PM. For example on the CRU block there is a particular sequence that needs
to be followed to initialize the CSI-2 D-PHY in which individual clocks
need to be turned ON/OFF, due to which Runtime PM support wasn't used by
the CRU CSI-2 driver.

This patch adds support to allow indicating if PM is not supported by the
CPG_MOD clocks. Two new members no_pm_mod_clks and num_no_pm_mod_clks are
added to struct rzg2l_cpg_info so that MOD clocks which do not support PM
can be passed by no_pm_mod_clks[] array and when the driver uses Runtime
PM support the clk ID is matched against the no_pm_mod_clks[] array to see
if the clk is needed to be included as part of Runtime PM.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20221026014227.162121-2-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

drivers/clk/renesas/rzg2l-cpg.c

@@ -95,6 +95,7 @@ struct rzg2l_pll5_mux_dsi_div_param {
  * @num_resets: Number of Module Resets in info->resets[]
  * @last_dt_core_clk: ID of the last Core Clock exported to DT
  * @info: Pointer to platform data
+ * @genpd: PM domain
  * @mux_dsi_div_params: pll5 mux and dsi div parameters
  */
 struct rzg2l_cpg_priv {
@@ -111,6 +112,8 @@ struct rzg2l_cpg_priv {
 
 	const struct rzg2l_cpg_info *info;
 
+	struct generic_pm_domain genpd;
+
 	struct rzg2l_pll5_mux_dsi_div_param mux_dsi_div_params;
 };
 
@@ -1223,22 +1226,31 @@ 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(const struct of_phandle_args *clkspec)
+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;
 
-	switch (clkspec->args[0]) {
-	case CPG_MOD:
-		return true;
-
-	default:
+	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;
 }
 
-static int rzg2l_cpg_attach_dev(struct generic_pm_domain *unused, struct device *dev)
+static int rzg2l_cpg_attach_dev(struct generic_pm_domain *domain, struct device *dev)
 {
+	struct rzg2l_cpg_priv *priv = container_of(domain, struct rzg2l_cpg_priv, genpd);
 	struct device_node *np = dev->of_node;
 	struct of_phandle_args clkspec;
 	bool once = true;
@@ -1248,7 +1260,7 @@ static int rzg2l_cpg_attach_dev(struct generic_pm_domain *unused, struct device
 
 	while (!of_parse_phandle_with_args(np, "clocks", "#clock-cells", i,
 					   &clkspec)) {
-		if (rzg2l_cpg_is_pm_clk(&clkspec)) {
+		if (rzg2l_cpg_is_pm_clk(priv, &clkspec)) {
 			if (once) {
 				once = false;
 				error = pm_clk_create(dev);
@@ -1298,16 +1310,13 @@ static void rzg2l_cpg_genpd_remove(void *data)
 	pm_genpd_remove(data);
 }
 
-static int __init rzg2l_cpg_add_clk_domain(struct device *dev)
+static int __init rzg2l_cpg_add_clk_domain(struct rzg2l_cpg_priv *priv)
 {
+	struct device *dev = priv->dev;
 	struct device_node *np = dev->of_node;
-	struct generic_pm_domain *genpd;
+	struct generic_pm_domain *genpd = &priv->genpd;
 	int ret;
 
-	genpd = devm_kzalloc(dev, sizeof(*genpd), GFP_KERNEL);
-	if (!genpd)
-		return -ENOMEM;
-
 	genpd->name = np->name;
 	genpd->flags = GENPD_FLAG_PM_CLK | GENPD_FLAG_ALWAYS_ON |
 		       GENPD_FLAG_ACTIVE_WAKEUP;
@@ -1377,7 +1386,7 @@ static int __init rzg2l_cpg_probe(struct platform_device *pdev)
 	if (error)
 		return error;
 
-	error = rzg2l_cpg_add_clk_domain(dev);
+	error = rzg2l_cpg_add_clk_domain(priv);
 	if (error)
 		return error;
 

drivers/clk/renesas/rzg2l-cpg.h

@@ -256,6 +256,10 @@ struct rzg2l_cpg_info {
 	unsigned int num_mod_clks;
 	unsigned int num_hw_mod_clks;
 
+	/* No PM Module Clocks */
+	const unsigned int *no_pm_mod_clks;
+	unsigned int num_no_pm_mod_clks;
+
 	/* Resets */
 	const struct rzg2l_reset *resets;
 	unsigned int num_resets;