linux-kernel - Re: [PATCH v2 1/2] watchdog: sp805_wdt: deassert the reset if available

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Message-ID: <7c3246e94de0fdad3f9bed50d46f70327ef30ef9.camel@pengutronix.de>
Date: Wed, 21 Feb 2024 12:48:46 +0100
From: Philipp Zabel <p.zabel@...gutronix.de>
To: forbidden405@...look.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>, Conor Dooley
 <conor+dt@...nel.org>,  Viresh Kumar <vireshk@...nel.org>
Cc: linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org, 
	devicetree@...r.kernel.org
Subject: Re: [PATCH v2 1/2] watchdog: sp805_wdt: deassert the reset if
 available

On Di, 2024-02-20 at 02:14 +0800, Yang Xiwen via B4 Relay wrote:
> From: Yang Xiwen <forbidden405@...look.com>
> 
> According to the datasheet, the core has an WDOGRESn input signal that
> needs to be deasserted before being operational. Implement it in the
> driver.
> 
> Signed-off-by: Yang Xiwen <forbidden405@...look.com>
> ---
>  drivers/watchdog/sp805_wdt.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/watchdog/sp805_wdt.c b/drivers/watchdog/sp805_wdt.c
> index 2756ed54ca3d..b4bcfdeb39e6 100644
> --- a/drivers/watchdog/sp805_wdt.c
> +++ b/drivers/watchdog/sp805_wdt.c
> @@ -25,6 +25,7 @@
>  #include <linux/moduleparam.h>
>  #include <linux/pm.h>
>  #include <linux/property.h>
> +#include <linux/reset.h>
>  #include <linux/slab.h>
>  #include <linux/spinlock.h>
>  #include <linux/types.h>
> @@ -59,6 +60,7 @@
>   * @lock: spin lock protecting dev structure and io access
>   * @base: base address of wdt
>   * @clk: (optional) clock structure of wdt
> + * @rst: (optional) reset control signal of wdt
>   * @rate: (optional) clock rate when provided via properties
>   * @adev: amba device structure of wdt
>   * @status: current status of wdt
> @@ -69,6 +71,7 @@ struct sp805_wdt {
>  	spinlock_t			lock;
>  	void __iomem			*base;
>  	struct clk			*clk;
> +	struct reset_control		*rst;

This can be a local variable in sp805_wdt_probe().

>  	u64				rate;
>  	struct amba_device		*adev;
>  	unsigned int			load_val;
> @@ -264,6 +267,12 @@ sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
>  		return -ENODEV;
>  	}
>  
> +	wdt->rst = devm_reset_control_get_optional(&adev->dev, NULL);

Please use devm_reset_control_get_optional_exclusive() directly.

> +	if (IS_ERR(wdt->rst))
> +		return dev_err_probe(&adev->dev, PTR_ERR(wdt->rst), "Can not get reset\n");
> +
> +	reset_control_deassert(wdt->rst);
> +
>  	wdt->adev = adev;
>  	wdt->wdd.info = &wdt_info;
>  	wdt->wdd.ops = &wdt_ops;

regards
Philipp