linux-kernel - RE: [PATCH 1/2] watchdog: rzg2l_wdt: Issue a reset before we put the PM clocks

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Date:   Wed, 8 Feb 2023 07:52:06 +0000
From:   Biju Das <biju.das.jz@...renesas.com>
To:     Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Geert Uytterhoeven <geert+renesas@...der.be>
CC:     Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@...renesas.com>,
        "linux-watchdog@...r.kernel.org" <linux-watchdog@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Chris Paterson <Chris.Paterson2@...esas.com>,
        Biju Das <biju.das@...renesas.com>,
        Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...r.kernel.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Jacopo Mondi <jacopo@...ndi.org>
Subject: RE: [PATCH 1/2] watchdog: rzg2l_wdt: Issue a reset before we put the
 PM clocks

Hi Fabrizio,

Thanks for the patch.

> Subject: [PATCH 1/2] watchdog: rzg2l_wdt: Issue a reset before we put the PM
> clocks
> 
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> 
> On RZ/Five SoC it was observed that setting timeout (to say 1 sec) wouldn't
> reset the system.
> 
> The procedure described in the HW manual (Procedure for Activating Modules)
> for activating the target module states we need to start supply of the clock
> module before applying the reset signal. This patch makes sure we follow the
> same procedure to clear the registers of the WDT module, fixing the issues
> seen on RZ/Five SoC.
> 
> While at it re-used rzg2l_wdt_stop() in rzg2l_wdt_set_timeout() as it has
> the same function calls.
> 
> Fixes: 4055ee81009e ("watchdog: rzg2l_wdt: Add set_timeout callback")
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>

Reviewed-by: Biju Das <biju.das.jz@...renesas.com>

Cheers,
Biju

> ---
>  drivers/watchdog/rzg2l_wdt.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
> index 974a4194a8fd..ceca42db0837 100644
> --- a/drivers/watchdog/rzg2l_wdt.c
> +++ b/drivers/watchdog/rzg2l_wdt.c
> @@ -115,25 +115,23 @@ static int rzg2l_wdt_stop(struct watchdog_device
> *wdev)  {
>  	struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
> 
> -	pm_runtime_put(wdev->parent);
>  	reset_control_reset(priv->rstc);
> +	pm_runtime_put(wdev->parent);
> 
>  	return 0;
>  }
> 
>  static int rzg2l_wdt_set_timeout(struct watchdog_device *wdev, unsigned int
> timeout)  {
> -	struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
> -
>  	wdev->timeout = timeout;
> 
>  	/*
>  	 * If the watchdog is active, reset the module for updating the WDTSET
> -	 * register so that it is updated with new timeout values.
> +	 * register by calling rzg2l_wdt_stop() (which internally calls
> reset_control_reset()
> +	 * to reset the module) so that it is updated with new timeout values.
>  	 */
>  	if (watchdog_active(wdev)) {
> -		pm_runtime_put(wdev->parent);
> -		reset_control_reset(priv->rstc);
> +		rzg2l_wdt_stop(wdev);
>  		rzg2l_wdt_start(wdev);
>  	}
> 
> --
> 2.34.1