linux-kernel - Re: [PATCH v3 07/12] watchdog: s3c2410: Implement a way to invert mask reg value

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Message-ID: <20211117133551.GG2435591@roeck-us.net>
Date:   Wed, 17 Nov 2021 05:35:51 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Sam Protsenko <semen.protsenko@...aro.org>
Cc:     Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org
Subject: Re: [PATCH v3 07/12] watchdog: s3c2410: Implement a way to invert
 mask reg value

On Sun, Nov 07, 2021 at 10:29:38PM +0200, Sam Protsenko wrote:
> On new Exynos chips (like Exynos850) the MASK_WDT_RESET_REQUEST register
> is replaced with CLUSTERx_NONCPU_INT_EN, and its mask bit value meaning
> was reversed: for new register the bit value "1" means "Interrupt
> enabled", while for MASK_WDT_RESET_REQUEST register "1" means "Mask the
> interrupt" (i.e. "Interrupt disabled").
> 
> Introduce "mask_reset_inv" boolean field in driver data structure; when
> that field is "true", mask register handling function will invert the
> value before setting it to the register.
> 
> 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@...aro.org>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>

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

> ---
> Changes in v3:
>   - Added R-b tag by Krzysztof Kozlowski
> 
> Changes in v2:
>   - (none): it's a new patch
> 
>  drivers/watchdog/s3c2410_wdt.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
> index 4ac0a30e835e..2a61b6ea5602 100644
> --- a/drivers/watchdog/s3c2410_wdt.c
> +++ b/drivers/watchdog/s3c2410_wdt.c
> @@ -92,6 +92,7 @@ MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to
>   * timer reset functionality.
>   * @mask_reset_reg: Offset in pmureg for the register that masks the watchdog
>   * timer reset functionality.
> + * @mask_reset_inv: If set, mask_reset_reg value will have inverted meaning.
>   * @mask_bit: Bit number for the watchdog timer in the disable register and the
>   * mask reset register.
>   * @rst_stat_reg: Offset in pmureg for the register that has the reset status.
> @@ -103,6 +104,7 @@ MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to
>  struct s3c2410_wdt_variant {
>  	int disable_reg;
>  	int mask_reset_reg;
> +	bool mask_reset_inv;
>  	int mask_bit;
>  	int rst_stat_reg;
>  	int rst_stat_bit;
> @@ -219,7 +221,8 @@ static int s3c2410wdt_disable_wdt_reset(struct s3c2410_wdt *wdt, bool mask)
>  static int s3c2410wdt_mask_wdt_reset(struct s3c2410_wdt *wdt, bool mask)
>  {
>  	const u32 mask_val = BIT(wdt->drv_data->mask_bit);
> -	const u32 val = mask ? mask_val : 0;
> +	const bool val_inv = wdt->drv_data->mask_reset_inv;
> +	const u32 val = (mask ^ val_inv) ? mask_val : 0;
>  	int ret;
>  
>  	ret = regmap_update_bits(wdt->pmureg, wdt->drv_data->mask_reset_reg,
> -- 
> 2.30.2
>