[PATCH v4 1/2] clk: renesas: rzv2h-cpg: Skip monitor checks for external clocks

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>

For module clocks whose parent mux may select an external source, bypass
the normal monitor (CLK_MON) register check when the external clock is
active. Introduce a new `ext_clk_mux_index` in `struct rzv2h_mod_clk` and
`struct mod_clock`, and detect the current mux index in
`rzv2h_mod_clock_is_enabled()` to disable monitoring if it matches the
external source index.

Provide the `DEF_MOD_MUX_EXTERNAL()` macro for declaring external-source
module clocks, and populate the `ext_clk_mux_index` field in
`rzv2h_cpg_register_mod_clk()`.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
---
v3->v4:
- Dropped external_clk_mux_index and external_clk and introduced
  ext_clk_mux_index.
- Updated DEF_MOD_*() macros to include ext_clk_mux_index.
- Added a new helper function `rzv2h_clk_mux_to_index()` to get the
  current mux index.
- Dropped IS_ERR() check for parent_clk in `rzv2h_clk_mux_to_index()`.
- Updated commit description to clarify the purpose of the patch.

v2->v3:
- Renamed helper macro to `DEF_MOD_MUX_EXTERNAL()`.
- Added a new field `external_clk_mux_index` to `struct mod_clock` to
  store the mux index corresponding to the external input.
- Updated the `rzv2h_mod_clock_is_enabled()` function to check if the
  parent mux selects the external source by comparing the current mux
  index against `external_clk_mux_index`.
- Updated the `rzv2h_cpg_register_mod_clk()` function to populate the new
  fields from the SoC info.
- Updated commit description

v1->v2:
- None
---
 drivers/clk/renesas/rzv2h-cpg.c | 29 ++++++++++++++++++++++++++++-
 drivers/clk/renesas/rzv2h-cpg.h | 17 +++++++++++++----
 2 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/renesas/rzv2h-cpg.c b/drivers/clk/renesas/rzv2h-cpg.c
index bcc496e8cbcd..882e301c2d1b 100644
--- a/drivers/clk/renesas/rzv2h-cpg.c
+++ b/drivers/clk/renesas/rzv2h-cpg.c
@@ -119,6 +119,7 @@ struct pll_clk {
  * @on_bit: ON/MON bit
  * @mon_index: monitor register offset
  * @mon_bit: monitor bit
+ * @ext_clk_mux_index: mux index for external clock source, or -1 if internal
  */
 struct mod_clock {
 	struct rzv2h_cpg_priv *priv;
@@ -129,6 +130,7 @@ struct mod_clock {
 	u8 on_bit;
 	s8 mon_index;
 	u8 mon_bit;
+	s8 ext_clk_mux_index;
 };
 
 #define to_mod_clock(_hw) container_of(_hw, struct mod_clock, hw)
@@ -563,14 +565,38 @@ static void rzv2h_mod_clock_mstop_disable(struct rzv2h_cpg_priv *priv,
 	spin_unlock_irqrestore(&priv->rmw_lock, flags);
 }
 
+static int rzv2h_clk_mux_to_index(struct clk_hw *hw)
+{
+	struct clk_hw *parent_hw;
+	struct clk *parent_clk;
+	struct clk_mux *mux;
+	u32 val;
+
+	/* This will always succeed, so no need to check for IS_ERR() */
+	parent_clk = clk_get_parent(hw->clk);
+
+	parent_hw = __clk_get_hw(parent_clk);
+	mux = to_clk_mux(parent_hw);
+
+	val = readl(mux->reg) >> mux->shift;
+	val &= mux->mask;
+	return clk_mux_val_to_index(parent_hw, mux->table, 0, val);
+}
+
 static int rzv2h_mod_clock_is_enabled(struct clk_hw *hw)
 {
 	struct mod_clock *clock = to_mod_clock(hw);
 	struct rzv2h_cpg_priv *priv = clock->priv;
+	int mon_index = clock->mon_index;
 	u32 bitmask;
 	u32 offset;
 
-	if (clock->mon_index >= 0) {
+	if (clock->ext_clk_mux_index >= 0) {
+		if (rzv2h_clk_mux_to_index(hw) == clock->ext_clk_mux_index)
+			mon_index = -1;
+	}
+
+	if (mon_index >= 0) {
 		offset = GET_CLK_MON_OFFSET(clock->mon_index);
 		bitmask = BIT(clock->mon_bit);
 
@@ -687,6 +713,7 @@ rzv2h_cpg_register_mod_clk(const struct rzv2h_mod_clk *mod,
 	clock->mon_index = mod->mon_index;
 	clock->mon_bit = mod->mon_bit;
 	clock->no_pm = mod->no_pm;
+	clock->ext_clk_mux_index = mod->ext_clk_mux_index;
 	clock->priv = priv;
 	clock->hw.init = &init;
 	clock->mstop_data = mod->mstop_data;
diff --git a/drivers/clk/renesas/rzv2h-cpg.h b/drivers/clk/renesas/rzv2h-cpg.h
index 9104b1cd276c..68c223373916 100644
--- a/drivers/clk/renesas/rzv2h-cpg.h
+++ b/drivers/clk/renesas/rzv2h-cpg.h
@@ -199,6 +199,7 @@ enum clk_types {
  * @on_bit: ON bit
  * @mon_index: monitor register index
  * @mon_bit: monitor bit
+ * @ext_clk_mux_index: mux index for external clock source, or -1 if internal
  */
 struct rzv2h_mod_clk {
 	const char *name;
@@ -210,9 +211,11 @@ struct rzv2h_mod_clk {
 	u8 on_bit;
 	s8 mon_index;
 	u8 mon_bit;
+	s8 ext_clk_mux_index;
 };
 
-#define DEF_MOD_BASE(_name, _mstop, _parent, _critical, _no_pm, _onindex, _onbit, _monindex, _monbit) \
+#define DEF_MOD_BASE(_name, _mstop, _parent, _critical, _no_pm, _onindex, \
+		     _onbit, _monindex, _monbit, _ext_clk_mux_index) \
 	{ \
 		.name = (_name), \
 		.mstop_data = (_mstop), \
@@ -223,16 +226,22 @@ struct rzv2h_mod_clk {
 		.on_bit = (_onbit), \
 		.mon_index = (_monindex), \
 		.mon_bit = (_monbit), \
+		.ext_clk_mux_index = (_ext_clk_mux_index), \
 	}
 
 #define DEF_MOD(_name, _parent, _onindex, _onbit, _monindex, _monbit, _mstop) \
-	DEF_MOD_BASE(_name, _mstop, _parent, false, false, _onindex, _onbit, _monindex, _monbit)
+	DEF_MOD_BASE(_name, _mstop, _parent, false, false, _onindex, _onbit, _monindex, _monbit, -1)
 
 #define DEF_MOD_CRITICAL(_name, _parent, _onindex, _onbit, _monindex, _monbit, _mstop) \
-	DEF_MOD_BASE(_name, _mstop, _parent, true, false, _onindex, _onbit, _monindex, _monbit)
+	DEF_MOD_BASE(_name, _mstop, _parent, true, false, _onindex, _onbit, _monindex, _monbit, -1)
 
 #define DEF_MOD_NO_PM(_name, _parent, _onindex, _onbit, _monindex, _monbit, _mstop) \
-	DEF_MOD_BASE(_name, _mstop, _parent, false, true, _onindex, _onbit, _monindex, _monbit)
+	DEF_MOD_BASE(_name, _mstop, _parent, false, true, _onindex, _onbit, _monindex, _monbit, -1)
+
+#define DEF_MOD_MUX_EXTERNAL(_name, _parent, _onindex, _onbit, _monindex, _monbit, _mstop, \
+			     _ext_clk_mux_index) \
+	DEF_MOD_BASE(_name, _mstop, _parent, false, false, _onindex, _onbit, _monindex, _monbit, \
+		     _ext_clk_mux_index)
 
 /**
  * struct rzv2h_reset - Reset definitions
-- 
2.49.0