linux-kernel - Re: [PATCH v4 2/4] watchdog: da9062: reset board on watchdog timeout

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Date:   Thu, 2 Dec 2021 06:41:13 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Andrej Picej <andrej.picej@...ik.com>
Cc:     support.opensource@...semi.com, linux-watchdog@...r.kernel.org,
        wim@...ux-watchdog.org, linux-kernel@...r.kernel.org,
        robh+dt@...nel.org, devicetree@...r.kernel.org,
        shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
        festevam@...il.com, linux-imx@....com,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 2/4] watchdog: da9062: reset board on watchdog timeout

On Thu, Dec 02, 2021 at 10:32:28AM +0100, Andrej Picej wrote:
> Implement a method to change watchdog timeout configuration based on DT
> binding ("dlg,wdt-sd"). There is a possibility to change the bahaviour
> of watchdog reset. Setting WATCHDOG_SD bit enables SHUTDOWN mode, and
> clearing it enables POWERDOWN mode on watchdog timeout.
> 
> If no DT binding is specified the WATCHDOG_SD bit stays in default
> configuration, not breaking behaviour of devices which might depend on
> default fuse configuration.
> 
> Note: This patch requires that the config register CONFIG_I is
> configured as writable in the da9062 multi function device.
> 
> Signed-off-by: Andrej Picej <andrej.picej@...ik.com>

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

> ---
> Chnages in v4:
>  - move the code to probe function
> 
> Changes in v3:
>  - no changes
> 
> Changes in v2:
>  - don't force the "reset" for all da9062-watchdog users, instead add DT
>    binding where the behavior can be selected
> ---
>  drivers/watchdog/da9062_wdt.c | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
> index f02cbd530538..bd85f84b0fd4 100644
> --- a/drivers/watchdog/da9062_wdt.c
> +++ b/drivers/watchdog/da9062_wdt.c
> @@ -195,8 +195,11 @@ static int da9062_wdt_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	unsigned int timeout;
> +	unsigned int mask;
>  	struct da9062 *chip;
>  	struct da9062_watchdog *wdt;
> +	int ret;
> +	u32 val;
>  
>  	chip = dev_get_drvdata(dev->parent);
>  	if (!chip)
> @@ -236,6 +239,30 @@ static int da9062_wdt_probe(struct platform_device *pdev)
>  		set_bit(WDOG_HW_RUNNING, &wdt->wdtdev.status);
>  	}
>  
> +	/*
> +	 * Configure what happens on watchdog timeout. Can be specified with
> +	 * "dlg,wdt-sd" dt-binding (0 -> POWERDOWN, 1 -> SHUTDOWN).
> +	 * If "dlg,wdt-sd" dt-binding is NOT set use the default.
> +	 */
> +	ret = device_property_read_u32(dev, "dlg,wdt-sd", &val);
> +	if (!ret) {
> +		if (val)
> +			/* Use da9062's SHUTDOWN mode */
> +			mask = DA9062AA_WATCHDOG_SD_MASK;
> +		else
> +			/* Use da9062's POWERDOWN mode. */
> +			mask = 0x0;
> +
> +		ret = regmap_update_bits(wdt->hw->regmap,
> +						DA9062AA_CONFIG_I,
> +						DA9062AA_WATCHDOG_SD_MASK,
> +						mask);
> +
> +		if (ret)
> +			dev_err(dev, "failed to set wdt reset mode: %d\n",
> +				ret);
> +	}
> +
>  	return devm_watchdog_register_device(dev, &wdt->wdtdev);
>  }
>  
> -- 
> 2.25.1
>