linux-kernel - [PATCH v2 3/9] clk: renesas: rzv2h-cpg: Support static dividers without RMW

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Message-ID: <20250407165202.197570-4-prabhakar.mahadev-lad.rj@bp.renesas.com>
Date: Mon,  7 Apr 2025 17:51:56 +0100
From: Prabhakar <prabhakar.csengg@...il.com>
To: Geert Uytterhoeven <geert+renesas@...der.be>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Magnus Damm <magnus.damm@...il.com>
Cc: linux-renesas-soc@...r.kernel.org,
	linux-clk@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org,
	Prabhakar <prabhakar.csengg@...il.com>,
	Biju Das <biju.das.jz@...renesas.com>,
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: [PATCH v2 3/9] clk: renesas: rzv2h-cpg: Support static dividers without RMW

From: Biju Das <biju.das.jz@...renesas.com>

Add support for static dividers that do not require read-modify-write (RMW)
operations. This enables the use of the generic clk_divider_ops instead of
the custom RMW-based implementation.

Signed-off-by: Biju Das <biju.das.jz@...renesas.com>
Co-developed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
---
 drivers/clk/renesas/rzv2h-cpg.c |  5 ++++-
 drivers/clk/renesas/rzv2h-cpg.h | 12 ++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/renesas/rzv2h-cpg.c b/drivers/clk/renesas/rzv2h-cpg.c
index 4123c30e8663..e53cd31c218e 100644
--- a/drivers/clk/renesas/rzv2h-cpg.c
+++ b/drivers/clk/renesas/rzv2h-cpg.c
@@ -380,7 +380,10 @@ rzv2h_cpg_ddiv_clk_register(const struct cpg_core_clk *core,
 		return ERR_PTR(-ENOMEM);
 
 	init.name = core->name;
-	init.ops = &rzv2h_ddiv_clk_divider_ops;
+	if (cfg_ddiv.no_rmw)
+		init.ops = &clk_divider_ops;
+	else
+		init.ops = &rzv2h_ddiv_clk_divider_ops;
 	init.parent_names = &parent_name;
 	init.num_parents = 1;
 
diff --git a/drivers/clk/renesas/rzv2h-cpg.h b/drivers/clk/renesas/rzv2h-cpg.h
index 00b52b459aad..97054f207113 100644
--- a/drivers/clk/renesas/rzv2h-cpg.h
+++ b/drivers/clk/renesas/rzv2h-cpg.h
@@ -37,12 +37,15 @@ struct pll {
  * @shift: position of the divider bit
  * @width: width of the divider
  * @monbit: monitor bit in CPG_CLKSTATUS0 register
+ * @no_rmw: flag to indicate if the register is read-modify-write
+ *        (1: no RMW, 0: RMW)
  */
 struct ddiv {
 	unsigned int offset:11;
 	unsigned int shift:4;
 	unsigned int width:4;
 	unsigned int monbit:5;
+	unsigned int no_rmw:1;
 };
 
 /*
@@ -61,6 +64,15 @@ struct ddiv {
 		.monbit = _monbit \
 	})
 
+#define DDIV_PACK_NO_RMW(_offset, _shift, _width, _monbit) \
+	((struct ddiv){ \
+		.offset = (_offset), \
+		.shift = (_shift), \
+		.width = (_width), \
+		.monbit = (_monbit), \
+		.no_rmw = 1 \
+	})
+
 /**
  * struct smuxed - Structure for static muxed clocks
  *
-- 
2.49.0