[RFC PATCH 1/2] clk: renesas: rzg2l: Don't assume all CPG_MOD clocks support PM

[Prabhakar <prabhakar.csengg@gmail.com>]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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 supported by the
CPG_MOD clocks. A new macro is DEF_NO_PM() is added which sets the no_pm
flag in struct rzg2l_mod_clk and when the driver uses Runtime PM support
no_pm flag is checked to see if the clk needs to included as part of
Runtime PM.

CPG_MOD clocks with no_pm flag set need to be individually turned ON/OFF
depending on the requirement of the driver.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
 drivers/clk/renesas/rzg2l-cpg.c | 35 +++++++++++++++++++++++++++++----
 drivers/clk/renesas/rzg2l-cpg.h | 12 ++++++++---
 2 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c
index 3ff6ecd61756..d275324909e7 100644
--- a/drivers/clk/renesas/rzg2l-cpg.c
+++ b/drivers/clk/renesas/rzg2l-cpg.c
@@ -114,6 +114,8 @@ struct rzg2l_cpg_priv {
 	struct rzg2l_pll5_mux_dsi_div_param mux_dsi_div_params;
 };
 
+static struct rzg2l_cpg_priv *rzg2l_cpg_priv;
+
 static void rzg2l_cpg_del_clk_provider(void *data)
 {
 	of_clk_del_provider(data);
@@ -1223,18 +1225,42 @@ static int rzg2l_cpg_reset_controller_register(struct rzg2l_cpg_priv *priv)
 	return devm_reset_controller_register(priv->dev, &priv->rcdev);
 }
 
+static inline const struct rzg2l_mod_clk
+*rzg2l_get_mod_clk(const struct rzg2l_cpg_info *info, int id)
+{
+	unsigned int i;
+
+	id += info->num_total_core_clks;
+	for (i = 0; i < info->num_mod_clks; i++) {
+		if (info->mod_clks[i].id == id)
+			return &info->mod_clks[i];
+	}
+
+	return NULL;
+}
+
 static bool rzg2l_cpg_is_pm_clk(const struct of_phandle_args *clkspec)
 {
+	struct rzg2l_cpg_priv *priv = rzg2l_cpg_priv;
+	const struct rzg2l_cpg_info *info = priv->info;
+	const struct rzg2l_mod_clk *mod_clk;
+
 	if (clkspec->args_count != 2)
 		return false;
 
-	switch (clkspec->args[0]) {
-	case CPG_MOD:
-		return true;
+	if (clkspec->args[0] != CPG_MOD)
+		return false;
 
-	default:
+	if (clkspec->args[1] >= info->num_hw_mod_clks) {
+		dev_err(priv->dev, "Invalid clk index\n");
 		return false;
 	}
+
+	mod_clk = rzg2l_get_mod_clk(info, clkspec->args[1]);
+	if (mod_clk && mod_clk->no_pm)
+		return false;
+
+	return true;
 }
 
 static int rzg2l_cpg_attach_dev(struct generic_pm_domain *unused, struct device *dev)
@@ -1348,6 +1374,7 @@ static int __init rzg2l_cpg_probe(struct platform_device *pdev)
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
 
+	rzg2l_cpg_priv = priv;
 	nclks = info->num_total_core_clks + info->num_hw_mod_clks;
 	clks = devm_kmalloc_array(dev, nclks, sizeof(*clks), GFP_KERNEL);
 	if (!clks)
diff --git a/drivers/clk/renesas/rzg2l-cpg.h b/drivers/clk/renesas/rzg2l-cpg.h
index cecbdf5e4f93..1d68d3838392 100644
--- a/drivers/clk/renesas/rzg2l-cpg.h
+++ b/drivers/clk/renesas/rzg2l-cpg.h
@@ -176,6 +176,7 @@ enum clk_types {
  * @off: register offset
  * @bit: ON/MON bit
  * @is_coupled: flag to indicate coupled clock
+ * @no_pm: flag to indicate if clock doesn't support PM
  */
 struct rzg2l_mod_clk {
 	const char *name;
@@ -184,9 +185,10 @@ struct rzg2l_mod_clk {
 	u16 off;
 	u8 bit;
 	bool is_coupled;
+	bool no_pm;
 };
 
-#define DEF_MOD_BASE(_name, _id, _parent, _off, _bit, _is_coupled)	\
+#define DEF_MOD_BASE(_name, _id, _parent, _off, _bit, _is_coupled, _no_pm)	\
 	{ \
 		.name = _name, \
 		.id = MOD_CLK_BASE + (_id), \
@@ -194,13 +196,17 @@ struct rzg2l_mod_clk {
 		.off = (_off), \
 		.bit = (_bit), \
 		.is_coupled = (_is_coupled), \
+		.no_pm = (_no_pm), \
 	}
 
 #define DEF_MOD(_name, _id, _parent, _off, _bit)	\
-	DEF_MOD_BASE(_name, _id, _parent, _off, _bit, false)
+	DEF_MOD_BASE(_name, _id, _parent, _off, _bit, false, false)
 
 #define DEF_COUPLED(_name, _id, _parent, _off, _bit)	\
-	DEF_MOD_BASE(_name, _id, _parent, _off, _bit, true)
+	DEF_MOD_BASE(_name, _id, _parent, _off, _bit, true, false)
+
+#define DEF_NO_PM(_name, _id, _parent, _off, _bit)	\
+	DEF_MOD_BASE(_name, _id, _parent, _off, _bit, false, true)
 
 /**
  * struct rzg2l_reset - Reset definitions
-- 
2.25.1