Re: [PATCH v3 08/12] watchdog: s3c2410: Add support for WDT counter enable register

[Guenter Roeck <linux@roeck-us.net>]

On Sun, Nov 07, 2021 at 10:29:39PM +0200, Sam Protsenko wrote:
> On new Exynos chips (e.g. Exynos850) new CLUSTERx_NONCPU_OUT register is
> introduced, where CNT_EN_WDT bit must be enabled to make watchdog
> counter running. Add corresponding quirk and proper infrastructure to
> handle that register if the quirk is set.
> 
> This commit doesn't bring any functional change to existing devices, but
> merely provides an infrastructure for upcoming chips support.
> 
> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
> Changes in v3:
>   - Added R-b tag by Krzysztof Kozlowski
> 
> Changes in v2:
>   - Used quirks instead of callbacks for all added PMU registers
>   - Used BIT() macro
>   - Extracted cleanup code to separate patch to minimize changes and
>     ease the review and porting
> 
>  drivers/watchdog/s3c2410_wdt.c | 28 +++++++++++++++++++++++++++-
>  1 file changed, 27 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
> index 2a61b6ea5602..ec341c876225 100644
> --- a/drivers/watchdog/s3c2410_wdt.c
> +++ b/drivers/watchdog/s3c2410_wdt.c
> @@ -60,11 +60,13 @@
>  #define QUIRK_HAS_RST_STAT			(1 << 1)
>  #define QUIRK_HAS_WTCLRINT_REG			(1 << 2)
>  #define QUIRK_HAS_PMU_AUTO_DISABLE		(1 << 3)
> +#define QUIRK_HAS_PMU_CNT_EN			(1 << 4)
>  
>  /* These quirks require that we have a PMU register map */
>  #define QUIRKS_HAVE_PMUREG			(QUIRK_HAS_PMU_CONFIG | \
>  						 QUIRK_HAS_RST_STAT | \
> -						 QUIRK_HAS_PMU_AUTO_DISABLE)
> +						 QUIRK_HAS_PMU_AUTO_DISABLE | \
> +						 QUIRK_HAS_PMU_CNT_EN)
>  
>  static bool nowayout	= WATCHDOG_NOWAYOUT;
>  static int tmr_margin;
> @@ -98,6 +100,8 @@ MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to
>   * @rst_stat_reg: Offset in pmureg for the register that has the reset status.
>   * @rst_stat_bit: Bit number in the rst_stat register indicating a watchdog
>   * reset.
> + * @cnt_en_reg: Offset in pmureg for the register that enables WDT counter.
> + * @cnt_en_bit: Bit number for "watchdog counter enable" in cnt_en register.
>   * @quirks: A bitfield of quirks.
>   */
>  
> @@ -108,6 +112,8 @@ struct s3c2410_wdt_variant {
>  	int mask_bit;
>  	int rst_stat_reg;
>  	int rst_stat_bit;
> +	int cnt_en_reg;
> +	int cnt_en_bit;
>  	u32 quirks;
>  };
>  
> @@ -233,6 +239,20 @@ static int s3c2410wdt_mask_wdt_reset(struct s3c2410_wdt *wdt, bool mask)
>  	return ret;
>  }
>  
> +static int s3c2410wdt_enable_counter(struct s3c2410_wdt *wdt, bool en)
> +{
> +	const u32 mask_val = BIT(wdt->drv_data->cnt_en_bit);
> +	const u32 val = en ? mask_val : 0;
> +	int ret;
> +
> +	ret = regmap_update_bits(wdt->pmureg, wdt->drv_data->cnt_en_reg,
> +				 mask_val, val);
> +	if (ret < 0)
> +		dev_err(wdt->dev, "failed to update reg(%d)\n", ret);
> +
> +	return ret;
> +}
> +
>  static int s3c2410wdt_mask_and_disable_reset(struct s3c2410_wdt *wdt, bool mask)
>  {
>  	int ret;
> @@ -249,6 +269,12 @@ static int s3c2410wdt_mask_and_disable_reset(struct s3c2410_wdt *wdt, bool mask)
>  			return ret;
>  	}
>  
> +	if (wdt->drv_data->quirks & QUIRK_HAS_PMU_CNT_EN) {
> +		ret = s3c2410wdt_enable_counter(wdt, !mask);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
>  	return 0;
>  }
>  
> -- 
> 2.30.2
>