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Sender: Guenter Roeck <groeck7@gmail.com>
Subject: Re: [PATCH] watchdog: mtk: add disable_wdt_extrst support
To:     Fengquan Chen <Fengquan.Chen@mediatek.com>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        linux-watchdog@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org
Cc:     tinghan.shen@mediatek.com, randy.wu@mediatek.com,
        rex-bc.chen@mediatek.com, christine.zhu@mediatek.com,
        joe.yang@mediatek.com, zhishuang.zhang@mediatek.com
References: <1630569881-6032-1-git-send-email-Fengquan.Chen@mediatek.com>
 <1630569881-6032-2-git-send-email-Fengquan.Chen@mediatek.com>
From:   Guenter Roeck <linux@roeck-us.net>
Message-ID: <5fe9c774-c619-604e-1f74-12ff6bfe826f@roeck-us.net>
Date:   Thu, 2 Sep 2021 06:43:41 -0700
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On 9/2/21 1:04 AM, Fengquan Chen wrote:
> From: "fengquan.chen" <fengquan.chen@mediatek.com>

There should not be such From: line.

> 
> In some cases, we may need watchdog just to trigger an
> internal soc reset without sending any output signal.
> 
> Provide a disable_wdt_extrst parameter for configuration.
> We can disable or enable it just by configuring dts.
> 
> igned-off-by: Fengquan Chen <fengquan.chen@mediatek.com>

Missing "S".

> ---
>   drivers/watchdog/mtk_wdt.c | 7 +++++++
>   1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> index 97ca993..4824c07 100644
> --- a/drivers/watchdog/mtk_wdt.c
> +++ b/drivers/watchdog/mtk_wdt.c
> @@ -63,6 +63,7 @@ struct mtk_wdt_dev {
>   	void __iomem *wdt_base;
>   	spinlock_t lock; /* protects WDT_SWSYSRST reg */
>   	struct reset_controller_dev rcdev;
> +	bool disable_wdt_extrst;
>   };
>   
>   struct mtk_wdt_data {
> @@ -240,6 +241,8 @@ static int mtk_wdt_start(struct watchdog_device *wdt_dev)
>   
>   	reg = ioread32(wdt_base + WDT_MODE);
>   	reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
> +	if (mtk_wdt->disable_wdt_extrst)
> +		reg &= ~WDT_MODE_EXRST_EN;
>   	reg |= (WDT_MODE_EN | WDT_MODE_KEY);
>   	iowrite32(reg, wdt_base + WDT_MODE);
>   
> @@ -309,6 +312,10 @@ static int mtk_wdt_probe(struct platform_device *pdev)
>   		if (err)
>   			return err;
>   	}
> +
> +	mtk_wdt->disable_wdt_extrst =
> +		of_property_read_bool(dev->of_node, "disable_extrst");
> +

The new property needs to be documented and approved by a DT maintainer
(separate patch). Something like "mtk,disable-extrst" would probably be
a better property name.

Guenter