linux-kernel - Re: [PATCH v3 2/4] watchdog: da9062: reset board on watchdog timeout

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Message-ID: <fa9eb129-a152-4f22-9bf4-07bf27ec441f@roeck-us.net>
Date:   Wed, 1 Dec 2021 13:26:34 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Andrej Picej <andrej.picej@...ik.com>,
        support.opensource@...semi.com, linux-watchdog@...r.kernel.org
Cc:     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 v3 2/4] watchdog: da9062: reset board on watchdog timeout

On 12/1/21 12:15 AM, 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>
> ---
> 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 | 25 +++++++++++++++++++++++++
>   1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
> index f02cbd530538..e342e9e50cb1 100644
> --- a/drivers/watchdog/da9062_wdt.c
> +++ b/drivers/watchdog/da9062_wdt.c
> @@ -85,8 +85,33 @@ static int da9062_wdt_start(struct watchdog_device *wdd)
>   {
>   	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
>   	unsigned int selector;
> +	unsigned int mask;
> +	u32 val;
>   	int ret;
>   
> +	/* 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.
> +	 */

Please use standard multi-line comments. This is not the networking
subsystem.

Also, if you think this code should be here and not in the probe function,
as suggested by Adam, please provide a rationale.

Thanks,
Guenter

> +	ret = device_property_read_u32(wdd->parent, "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(wdt->hw->dev, "failed to set wdt reset mode: %d\n",
> +				ret);
> +	}
> +
>   	selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
>   	ret = da9062_wdt_update_timeout_register(wdt, selector);
>   	if (ret)
>