linux-kernel - [PATCH v2 2/9] watchdog: rzv2h_wdt: Obtain clock-divider ranges from OF match data

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Message-ID: <20250729155915.67758-3-prabhakar.mahadev-lad.rj@bp.renesas.com>
Date: Tue, 29 Jul 2025 16:59:08 +0100
From: Prabhakar <prabhakar.csengg@...il.com>
To: Wim Van Sebroeck <wim@...ux-watchdog.org>,
	Guenter Roeck <linux@...ck-us.net>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Magnus Damm <magnus.damm@...il.com>,
	Wolfram Sang <wsa+renesas@...g-engineering.com>
Cc: linux-watchdog@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-renesas-soc@...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 2/9] watchdog: rzv2h_wdt: Obtain clock-divider ranges from OF match data

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

Move the clock division ratio values into OF match data instead of
hardcoding them in the driver. Introduce `rzv2h_of_data` to hold `cks_min`
and `cks_max`, populated via the device tree match table. In probe, call
`of_device_get_match_data()` to retrieve these values for setting up the
watchdog.

This refactoring is transparent for existing RZ/V2H(P) usage and
facilitates adding RZ/T2H support with different divider ranges.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
---
v1->v2:
- No changes.
---
 drivers/watchdog/rzv2h_wdt.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c
index 8defd0241213..d64d29709160 100644
--- a/drivers/watchdog/rzv2h_wdt.c
+++ b/drivers/watchdog/rzv2h_wdt.c
@@ -45,12 +45,18 @@ module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 
+struct rzv2h_of_data {
+	u8 cks_min;
+	u8 cks_max;
+};
+
 struct rzv2h_wdt_priv {
 	void __iomem *base;
 	struct clk *pclk;
 	struct clk *oscclk;
 	struct reset_control *rstc;
 	struct watchdog_device wdev;
+	const struct rzv2h_of_data *of_data;
 };
 
 static int rzv2h_wdt_ping(struct watchdog_device *wdev)
@@ -106,7 +112,7 @@ static int rzv2h_wdt_start(struct watchdog_device *wdev)
 	 * - RPES[9:8] - Window End Position Select - 11b: 0%
 	 * - TOPS[1:0] - Timeout Period Select - 11b: 16384 cycles (3FFFh)
 	 */
-	rzv2h_wdt_setup(wdev, WDTCR_CKS_CLK_256 | WDTCR_RPSS_100 |
+	rzv2h_wdt_setup(wdev, priv->of_data->cks_max | WDTCR_RPSS_100 |
 			WDTCR_RPES_0 | WDTCR_TOPS_16384);
 
 	/*
@@ -184,7 +190,7 @@ static int rzv2h_wdt_restart(struct watchdog_device *wdev,
 	 * - RPES[9:8] - Window End Position Select - 00b: 75%
 	 * - TOPS[1:0] - Timeout Period Select - 00b: 1024 cycles (03FFh)
 	 */
-	rzv2h_wdt_setup(wdev, WDTCR_CKS_CLK_1 | WDTCR_RPSS_25 |
+	rzv2h_wdt_setup(wdev, priv->of_data->cks_min | WDTCR_RPSS_25 |
 			WDTCR_RPES_75 | WDTCR_TOPS_1024);
 
 	rzv2h_wdt_ping(wdev);
@@ -213,6 +219,8 @@ static int rzv2h_wdt_probe(struct platform_device *pdev)
 	if (!priv)
 		return -ENOMEM;
 
+	priv->of_data = of_device_get_match_data(dev);
+
 	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
@@ -254,8 +262,13 @@ static int rzv2h_wdt_probe(struct platform_device *pdev)
 	return devm_watchdog_register_device(dev, &priv->wdev);
 }
 
+static const struct rzv2h_of_data rzv2h_wdt_of_data = {
+	.cks_min = WDTCR_CKS_CLK_1,
+	.cks_max = WDTCR_CKS_CLK_256,
+};
+
 static const struct of_device_id rzv2h_wdt_ids[] = {
-	{ .compatible = "renesas,r9a09g057-wdt", },
+	{ .compatible = "renesas,r9a09g057-wdt", .data = &rzv2h_wdt_of_data },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, rzv2h_wdt_ids);
-- 
2.50.1