[PATCH 0/3] watchdog: rzv2h: Convert WDTDCR handling to regmap

[PATCH 0/3] watchdog: rzv2h: Convert WDTDCR handling to regmap

[Prabhakar]

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

Hi All,

This patch series converts the WDTDCR register access from raw
readl/writel variants over to the regmap framework using
devm_regmap_init_mmio(). This conversion serves as a preparatory
refactoring step. It allows the driver to subsequently support
syscon-based system controllers natively by passing along alternative
regmap handles without forcing messy architectural branching at runtime.

Note,
 - This change was suggested [0]
   [0] https://lore.kernel.org/all/c3ef312a-4c26-498c-90c8-118c6dc035a0@roeck-us.net/ 
- Patches are rebased on top of next-20260701

Cheers,
Prabhakar

Lad Prabhakar (3):
  watchdog: rzv2h: Refactor WDTDCR start/stop handling
  watchdog: rzv2h: Convert WDTDCR handling to regmap
  watchdog: rzv2h: Drop WDTRCR_RSTIRQS macro

 drivers/watchdog/rzv2h_wdt.c | 81 ++++++++++++++++++++++++++----------
 1 file changed, 59 insertions(+), 22 deletions(-)

-- 
2.54.0

[PATCH 1/3] watchdog: rzv2h: Refactor WDTDCR start/stop handling

[Prabhakar]

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

Refactor the WDTDCR start/stop helpers by introducing a common
rzt2h_wdt_wdtdcr_count_ctrl() function that controls the WDTSTOPCTRL
bit based on a boolean parameter.

This is in preparation for switching WDTDCR access to regmap-based
handling, where consolidating the control path simplifies the
conversion.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
 drivers/watchdog/rzv2h_wdt.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c
index 3b6abb66a1da..e9545b8f5fd0 100644
--- a/drivers/watchdog/rzv2h_wdt.c
+++ b/drivers/watchdog/rzv2h_wdt.c
@@ -89,18 +89,26 @@ static int rzv2h_wdt_ping(struct watchdog_device *wdev)
 	return 0;
 }
 
-static void rzt2h_wdt_wdtdcr_count_stop(struct rzv2h_wdt_priv *priv)
+static void rzt2h_wdt_wdtdcr_count_ctrl(struct rzv2h_wdt_priv *priv, bool start)
 {
 	u32 reg = readl(priv->wdtdcr + WDTDCR);
 
-	writel(reg | WDTDCR_WDTSTOPCTRL, priv->wdtdcr + WDTDCR);
+	if (start)
+		reg &= ~WDTDCR_WDTSTOPCTRL;
+	else
+		reg |= WDTDCR_WDTSTOPCTRL;
+
+	writel(reg, priv->wdtdcr + WDTDCR);
 }
 
-static void rzt2h_wdt_wdtdcr_count_start(struct rzv2h_wdt_priv *priv)
+static void rzt2h_wdt_wdtdcr_count_stop(struct rzv2h_wdt_priv *priv)
 {
-	u32 reg = readl(priv->wdtdcr + WDTDCR);
+	rzt2h_wdt_wdtdcr_count_ctrl(priv, false);
+}
 
-	writel(reg & ~WDTDCR_WDTSTOPCTRL, priv->wdtdcr + WDTDCR);
+static void rzt2h_wdt_wdtdcr_count_start(struct rzv2h_wdt_priv *priv)
+{
+	rzt2h_wdt_wdtdcr_count_ctrl(priv, true);
 }
 
 static void rzv2h_wdt_setup(struct watchdog_device *wdev, u16 wdtcr)
-- 
2.54.0

[PATCH 2/3] watchdog: rzv2h: Convert WDTDCR handling to regmap

[Prabhakar]

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

Convert the WDTDCR register access from raw readl/writel variants over to
the regmap framework using devm_regmap_init_mmio().

This conversion serves as a preparatory refactoring step. It allows the
driver to subsequently support syscon-based system controllers natively
by passing along alternative regmap handles without forcing messy
architectural branching at runtime.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
 drivers/watchdog/rzv2h_wdt.c | 83 +++++++++++++++++++++++++-----------
 1 file changed, 57 insertions(+), 26 deletions(-)

diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c
index e9545b8f5fd0..d0b38450cc32 100644
--- a/drivers/watchdog/rzv2h_wdt.c
+++ b/drivers/watchdog/rzv2h_wdt.c
@@ -12,6 +12,7 @@
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/regmap.h>
 #include <linux/reset.h>
 #include <linux/units.h>
 #include <linux/watchdog.h>
@@ -67,7 +68,7 @@ struct rzv2h_of_data {
 
 struct rzv2h_wdt_priv {
 	void __iomem *base;
-	void __iomem *wdtdcr;
+	struct regmap *wdtdcr_regmap;
 	struct clk *pclk;
 	struct clk *oscclk;
 	struct reset_control *rstc;
@@ -89,26 +90,20 @@ static int rzv2h_wdt_ping(struct watchdog_device *wdev)
 	return 0;
 }
 
-static void rzt2h_wdt_wdtdcr_count_ctrl(struct rzv2h_wdt_priv *priv, bool start)
+static int rzt2h_wdt_wdtdcr_count_ctrl(struct rzv2h_wdt_priv *priv, bool start)
 {
-	u32 reg = readl(priv->wdtdcr + WDTDCR);
-
-	if (start)
-		reg &= ~WDTDCR_WDTSTOPCTRL;
-	else
-		reg |= WDTDCR_WDTSTOPCTRL;
-
-	writel(reg, priv->wdtdcr + WDTDCR);
+	return regmap_update_bits(priv->wdtdcr_regmap, WDTDCR, WDTDCR_WDTSTOPCTRL,
+				  start ? 0 : WDTDCR_WDTSTOPCTRL);
 }
 
-static void rzt2h_wdt_wdtdcr_count_stop(struct rzv2h_wdt_priv *priv)
+static int rzt2h_wdt_wdtdcr_count_stop(struct rzv2h_wdt_priv *priv)
 {
-	rzt2h_wdt_wdtdcr_count_ctrl(priv, false);
+	return rzt2h_wdt_wdtdcr_count_ctrl(priv, false);
 }
 
-static void rzt2h_wdt_wdtdcr_count_start(struct rzv2h_wdt_priv *priv)
+static int rzt2h_wdt_wdtdcr_count_start(struct rzv2h_wdt_priv *priv)
 {
-	rzt2h_wdt_wdtdcr_count_ctrl(priv, true);
+	return rzt2h_wdt_wdtdcr_count_ctrl(priv, true);
 }
 
 static void rzv2h_wdt_setup(struct watchdog_device *wdev, u16 wdtcr)
@@ -158,8 +153,14 @@ static int rzv2h_wdt_start(struct watchdog_device *wdev)
 	rzv2h_wdt_setup(wdev, of_data->cks_max | WDTCR_RPSS_100 |
 			WDTCR_RPES_0 | of_data->tops);
 
-	if (priv->of_data->wdtdcr)
-		rzt2h_wdt_wdtdcr_count_start(priv);
+	if (priv->of_data->wdtdcr) {
+		ret = rzt2h_wdt_wdtdcr_count_start(priv);
+		if (ret) {
+			reset_control_assert(priv->rstc);
+			pm_runtime_put(wdev->parent);
+			return ret;
+		}
+	}
 
 	/*
 	 * Down counting starts after writing the sequence 00h -> FFh to the
@@ -179,8 +180,13 @@ static int rzv2h_wdt_stop(struct watchdog_device *wdev)
 	if (ret)
 		return ret;
 
-	if (priv->of_data->wdtdcr)
-		rzt2h_wdt_wdtdcr_count_stop(priv);
+	if (priv->of_data->wdtdcr) {
+		ret = rzt2h_wdt_wdtdcr_count_stop(priv);
+		if (ret) {
+			reset_control_deassert(priv->rstc);
+			return ret;
+		}
+	}
 
 	pm_runtime_put(wdev->parent);
 
@@ -196,9 +202,10 @@ static int rzv2h_wdt_restart(struct watchdog_device *wdev,
 			     unsigned long action, void *data)
 {
 	struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev);
+	bool active = watchdog_active(wdev);
 	int ret;
 
-	if (!watchdog_active(wdev)) {
+	if (!active) {
 		ret = clk_enable(priv->pclk);
 		if (ret)
 			return ret;
@@ -242,8 +249,17 @@ static int rzv2h_wdt_restart(struct watchdog_device *wdev,
 	rzv2h_wdt_setup(wdev, priv->of_data->cks_min | WDTCR_RPSS_25 |
 			WDTCR_RPES_75 | WDTCR_TOPS_1024);
 
-	if (priv->of_data->wdtdcr)
-		rzt2h_wdt_wdtdcr_count_start(priv);
+	if (priv->of_data->wdtdcr) {
+		ret = rzt2h_wdt_wdtdcr_count_start(priv);
+		if (ret) {
+			if (!active) {
+				reset_control_assert(priv->rstc);
+				clk_disable(priv->oscclk);
+				clk_disable(priv->pclk);
+			}
+			return ret;
+		}
+	}
 
 	rzv2h_wdt_ping(wdev);
 
@@ -261,24 +277,39 @@ static const struct watchdog_ops rzv2h_wdt_ops = {
 	.restart = rzv2h_wdt_restart,
 };
 
+static const struct regmap_config rzv2h_wdtdcr_regmap_config = {
+	.name = "wdtdcr",
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = WDTDCR,
+	.fast_io = true,
+};
+
 static int rzt2h_wdt_wdtdcr_init(struct platform_device *pdev,
 				 struct rzv2h_wdt_priv *priv)
 {
+	void __iomem *wdtdcr;
 	int ret;
 
-	priv->wdtdcr = devm_platform_ioremap_resource(pdev, 1);
-	if (IS_ERR(priv->wdtdcr))
-		return PTR_ERR(priv->wdtdcr);
+	wdtdcr = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(wdtdcr))
+		return PTR_ERR(wdtdcr);
+
+	priv->wdtdcr_regmap = devm_regmap_init_mmio(&pdev->dev, wdtdcr,
+						    &rzv2h_wdtdcr_regmap_config);
+	if (IS_ERR(priv->wdtdcr_regmap))
+		return PTR_ERR(priv->wdtdcr_regmap);
 
 	ret = pm_runtime_resume_and_get(&pdev->dev);
 	if (ret)
 		return ret;
 
-	rzt2h_wdt_wdtdcr_count_stop(priv);
+	ret = rzt2h_wdt_wdtdcr_count_stop(priv);
 
 	pm_runtime_put(&pdev->dev);
 
-	return 0;
+	return ret;
 }
 
 static int rzv2h_wdt_probe(struct platform_device *pdev)
-- 
2.54.0

[PATCH 3/3] watchdog: rzv2h: Drop WDTRCR_RSTIRQS macro

[Prabhakar]

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

WDTRCR_RSTIRQS macro is unused so drop it.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
 drivers/watchdog/rzv2h_wdt.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c
index d0b38450cc32..e36f3d3c98ea 100644
--- a/drivers/watchdog/rzv2h_wdt.c
+++ b/drivers/watchdog/rzv2h_wdt.c
@@ -40,8 +40,6 @@
 #define WDTCR_RPSS_25		0x00
 #define WDTCR_RPSS_100		0x3000
 
-#define WDTRCR_RSTIRQS		BIT(7)
-
 #define WDTDCR_WDTSTOPCTRL	BIT(0)
 
 #define WDT_DEFAULT_TIMEOUT	60U
-- 
2.54.0

Re: [PATCH 2/3] watchdog: rzv2h: Convert WDTDCR handling to regmap

[Philipp Zabel]

On Do, 2026-07-02 at 17:04 +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Convert the WDTDCR register access from raw readl/writel variants over to
> the regmap framework using devm_regmap_init_mmio().
> 
> This conversion serves as a preparatory refactoring step. It allows the
> driver to subsequently support syscon-based system controllers natively
> by passing along alternative regmap handles without forcing messy
> architectural branching at runtime.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
>  drivers/watchdog/rzv2h_wdt.c | 83 +++++++++++++++++++++++++-----------
>  1 file changed, 57 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c
> index e9545b8f5fd0..d0b38450cc32 100644
> --- a/drivers/watchdog/rzv2h_wdt.c
> +++ b/drivers/watchdog/rzv2h_wdt.c
> @@ -12,6 +12,7 @@
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
>  #include <linux/reset.h>
>  #include <linux/units.h>
>  #include <linux/watchdog.h>
> @@ -67,7 +68,7 @@ struct rzv2h_of_data {
>  
>  struct rzv2h_wdt_priv {
>  	void __iomem *base;
> -	void __iomem *wdtdcr;
> +	struct regmap *wdtdcr_regmap;
>  	struct clk *pclk;
>  	struct clk *oscclk;
>  	struct reset_control *rstc;
> @@ -89,26 +90,20 @@ static int rzv2h_wdt_ping(struct watchdog_device *wdev)
>  	return 0;
>  }
>  
> -static void rzt2h_wdt_wdtdcr_count_ctrl(struct rzv2h_wdt_priv *priv, bool start)
> +static int rzt2h_wdt_wdtdcr_count_ctrl(struct rzv2h_wdt_priv *priv, bool start)
>  {
> -	u32 reg = readl(priv->wdtdcr + WDTDCR);
> -
> -	if (start)
> -		reg &= ~WDTDCR_WDTSTOPCTRL;
> -	else
> -		reg |= WDTDCR_WDTSTOPCTRL;
> -
> -	writel(reg, priv->wdtdcr + WDTDCR);
> +	return regmap_update_bits(priv->wdtdcr_regmap, WDTDCR, WDTDCR_WDTSTOPCTRL,
> +				  start ? 0 : WDTDCR_WDTSTOPCTRL);
>  }

I would drop this helper function and just call regmap_set/clear_bits()
directly in rzt2h_wdt_wdtdcr_count_stop/start().

regards
Philipp

Re: [PATCH 2/3] watchdog: rzv2h: Convert WDTDCR handling to regmap

[Lad, Prabhakar]

Hi Philipp,

Thank you for the review.

On Fri, Jul 3, 2026 at 8:35 AM Philipp Zabel <p.zabel@pengutronix.de> wrote:
>
> On Do, 2026-07-02 at 17:04 +0100, Prabhakar wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > Convert the WDTDCR register access from raw readl/writel variants over to
> > the regmap framework using devm_regmap_init_mmio().
> >
> > This conversion serves as a preparatory refactoring step. It allows the
> > driver to subsequently support syscon-based system controllers natively
> > by passing along alternative regmap handles without forcing messy
> > architectural branching at runtime.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > ---
> >  drivers/watchdog/rzv2h_wdt.c | 83 +++++++++++++++++++++++++-----------
> >  1 file changed, 57 insertions(+), 26 deletions(-)
> >
> > diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c
> > index e9545b8f5fd0..d0b38450cc32 100644
> > --- a/drivers/watchdog/rzv2h_wdt.c
> > +++ b/drivers/watchdog/rzv2h_wdt.c
> > @@ -12,6 +12,7 @@
> >  #include <linux/of.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/pm_runtime.h>
> > +#include <linux/regmap.h>
> >  #include <linux/reset.h>
> >  #include <linux/units.h>
> >  #include <linux/watchdog.h>
> > @@ -67,7 +68,7 @@ struct rzv2h_of_data {
> >
> >  struct rzv2h_wdt_priv {
> >       void __iomem *base;
> > -     void __iomem *wdtdcr;
> > +     struct regmap *wdtdcr_regmap;
> >       struct clk *pclk;
> >       struct clk *oscclk;
> >       struct reset_control *rstc;
> > @@ -89,26 +90,20 @@ static int rzv2h_wdt_ping(struct watchdog_device *wdev)
> >       return 0;
> >  }
> >
> > -static void rzt2h_wdt_wdtdcr_count_ctrl(struct rzv2h_wdt_priv *priv, bool start)
> > +static int rzt2h_wdt_wdtdcr_count_ctrl(struct rzv2h_wdt_priv *priv, bool start)
> >  {
> > -     u32 reg = readl(priv->wdtdcr + WDTDCR);
> > -
> > -     if (start)
> > -             reg &= ~WDTDCR_WDTSTOPCTRL;
> > -     else
> > -             reg |= WDTDCR_WDTSTOPCTRL;
> > -
> > -     writel(reg, priv->wdtdcr + WDTDCR);
> > +     return regmap_update_bits(priv->wdtdcr_regmap, WDTDCR, WDTDCR_WDTSTOPCTRL,
> > +                               start ? 0 : WDTDCR_WDTSTOPCTRL);
> >  }
>
> I would drop this helper function and just call regmap_set/clear_bits()
> directly in rzt2h_wdt_wdtdcr_count_stop/start().
>
Ok, I will update as suggested and send a v2.

Cheers,
Prabhakar