linux-kernel - Re: [PATCH 2/2] watchdog: mtk_wdt: Add support for MT6735 WDT

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Date:   Thu, 2 Mar 2023 16:15:22 +0100
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     Yassine Oudjana <yassine.oudjana@...il.com>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Philipp Zabel <p.zabel@...gutronix.de>
Cc:     Yassine Oudjana <y.oudjana@...tonmail.com>,
        linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH 2/2] watchdog: mtk_wdt: Add support for MT6735 WDT

Il 02/03/23 13:40, Yassine Oudjana ha scritto:
> From: Yassine Oudjana <y.oudjana@...tonmail.com>
> 
> Add support for the watchdog timer/top reset generation unit found on MT6735.
> Disable WDT_MODE_IRQ_EN in mtk_wdt_restart in order to make TOPRGU assert
> the SYSRST pin instead of issuing an IRQ. This change may be needed in other
> SoCs as well.
> 
> Signed-off-by: Yassine Oudjana <y.oudjana@...tonmail.com>
> ---
>   drivers/watchdog/mtk_wdt.c | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
> index a9c437598e7e..5a7a7b2b3727 100644
> --- a/drivers/watchdog/mtk_wdt.c
> +++ b/drivers/watchdog/mtk_wdt.c
> @@ -10,6 +10,7 @@
>    */
>   
>   #include <dt-bindings/reset/mt2712-resets.h>
> +#include <dt-bindings/reset/mediatek,mt6735-wdt.h>
>   #include <dt-bindings/reset/mediatek,mt6795-resets.h>
>   #include <dt-bindings/reset/mt7986-resets.h>
>   #include <dt-bindings/reset/mt8183-resets.h>
> @@ -82,6 +83,10 @@ static const struct mtk_wdt_data mt2712_data = {
>   	.toprgu_sw_rst_num = MT2712_TOPRGU_SW_RST_NUM,
>   };
>   
> +static const struct mtk_wdt_data mt6735_data = {
> +	.toprgu_sw_rst_num = MT6735_TOPRGU_RST_NUM,
> +};
> +
>   static const struct mtk_wdt_data mt6795_data = {
>   	.toprgu_sw_rst_num = MT6795_TOPRGU_SW_RST_NUM,
>   };
> @@ -187,9 +192,15 @@ static int mtk_wdt_restart(struct watchdog_device *wdt_dev,
>   {
>   	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
>   	void __iomem *wdt_base;
> +	u32 reg;
>   
>   	wdt_base = mtk_wdt->wdt_base;
>   
> +	/* Enable reset in order to issue a system reset instead of an IRQ */
> +	reg = readl(wdt_base + WDT_MODE);
> +	reg &= ~WDT_MODE_IRQ_EN;
> +	writel(reg | WDT_MODE_KEY, wdt_base + WDT_MODE);

This is unnecessary and already done in mtk_wdt_start().
If you think you *require* this snippet, you most likely misconfigured the
devicetree node for your device :-)

Please remove this snippet.

Regards,
Angelo