Re: [PATCH v2] watchdog: make DesignWare watchdog allow users to set bigger timeout value

[Guenter Roeck]

On Thu, Nov 21, 2019 at 10:35:12AM +0000, Wang, Peng 1. (NSB - CN/Hangzhou) wrote:
> From aabaa4b709bd451e566c906e8d1dca48f92f9b12 Mon Sep 17 00:00:00 2001
> From: Peng Wang <peng.1.wang@xxxxxxxxxxxxxxx>
> Date: Wed, 20 Nov 2019 15:12:59 +0800
> Subject: [PATCH] watchdog: make DesignWare watchdog allow users to set bigger
>  timeout value
> 
> watchdog_dev.c provides means to allow users to set bigger timeout value
> than HW can support, make DesignWare watchdog align with this.
> 
> ---
> 
> v2 -> v1:
>        - use top_s to compare with wdd->max_hw_heartbeat_ms
>        - update wdd->timeout in case it's greater than HW supports
>        - fix comments error
> 
> v1: initial version
> 
> Signed-off-by: Peng Wang <peng.1.wang@xxxxxxxxxxxxxxx>

Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>

> ---
>  drivers/watchdog/dw_wdt.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
> index fef7c61..12c116e 100644
> --- a/drivers/watchdog/dw_wdt.c
> +++ b/drivers/watchdog/dw_wdt.c
> @@ -114,7 +114,15 @@ static int dw_wdt_set_timeout(struct watchdog_device *wdd, unsigned int top_s)
>  	writel(top_val | top_val << WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT,
>  	       dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
>  
> -	wdd->timeout = dw_wdt_top_in_seconds(dw_wdt, top_val);
> +	/*
> +	 * In case users set bigger timeout value than HW can support,
> +	 * kernel(watchdog_dev.c) helps to feed watchdog before 
> +	 * wdd->max_hw_heartbeat_ms
> +	 */
> +	if ( top_s * 1000 <= wdd->max_hw_heartbeat_ms )
> +		wdd->timeout = dw_wdt_top_in_seconds(dw_wdt, top_val);
> +	else
> +		wdd->timeout = top_s;
>  
>  	return 0;
>  }
> -- 
> 1.8.3.1
>