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

[Philipp Zabel <p.zabel@pengutronix.de>]

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