[3/5,v2] watchdog: ftwdt010: Make interrupt optional

[linux@roeck-us.net (Guenter Roeck)]

On Mon, Oct 16, 2017 at 10:54:25PM +0200, Linus Walleij wrote:
> The Moxart does not appear to be using the interrupt from the
> watchdog timer, maybe it's not even routed, so as to support
> more architectures with this driver, make the interrupt
> optional.
> 
> While we are at it: actually enable the use of the interrupt
> if present by setting the right bit in the control register
> and define the missing control register bits.
> 
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
> ChangeLog v1->v2:
> - Fix surplus flag assignment of enable |= WDCR_CLOCK_5MHZ
> ---
>  drivers/watchdog/ftwdt010_wdt.c | 30 ++++++++++++++++++------------
>  1 file changed, 18 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/watchdog/ftwdt010_wdt.c b/drivers/watchdog/ftwdt010_wdt.c
> index 637ffd812f0b..a9c2912ee280 100644
> --- a/drivers/watchdog/ftwdt010_wdt.c
> +++ b/drivers/watchdog/ftwdt010_wdt.c
> @@ -30,6 +30,8 @@
>  #define WDRESTART_MAGIC		0x5AB9
>  
>  #define WDCR_CLOCK_5MHZ		BIT(4)
> +#define WDCR_WDEXT		BIT(3)
> +#define WDCR_WDINTR		BIT(2)
>  #define WDCR_SYS_RST		BIT(1)
>  #define WDCR_ENABLE		BIT(0)
>  
> @@ -39,6 +41,7 @@ struct ftwdt010_wdt {
>  	struct watchdog_device	wdd;
>  	struct device		*dev;
>  	void __iomem		*base;
> +	bool			has_irq;
>  };
>  
>  static inline
> @@ -50,14 +53,17 @@ struct ftwdt010_wdt *to_ftwdt010_wdt(struct watchdog_device *wdd)
>  static int ftwdt010_wdt_start(struct watchdog_device *wdd)
>  {
>  	struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
> +	u32 enable;
>  
>  	writel(wdd->timeout * WDT_CLOCK, gwdt->base + FTWDT010_WDLOAD);
>  	writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART);
>  	/* set clock before enabling */
> -	writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST,
> -			gwdt->base + FTWDT010_WDCR);
> -	writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE,
> -			gwdt->base + FTWDT010_WDCR);
> +	enable = WDCR_CLOCK_5MHZ | WDCR_SYS_RST;
> +	writel(enable, gwdt->base + FTWDT010_WDCR);
> +	if (gwdt->has_irq)
> +		enable |= WDCR_WDINTR;
> +	enable |= WDCR_ENABLE;
> +	writel(enable, gwdt->base + FTWDT010_WDCR);
>  
>  	return 0;
>  }
> @@ -133,10 +139,6 @@ static int ftwdt010_wdt_probe(struct platform_device *pdev)
>  	if (IS_ERR(gwdt->base))
>  		return PTR_ERR(gwdt->base);
>  
> -	irq = platform_get_irq(pdev, 0);
> -	if (!irq)
> -		return -EINVAL;
> -
>  	gwdt->dev = dev;
>  	gwdt->wdd.info = &ftwdt010_wdt_info;
>  	gwdt->wdd.ops = &ftwdt010_wdt_ops;
> @@ -158,10 +160,14 @@ static int ftwdt010_wdt_probe(struct platform_device *pdev)
>  		writel(reg, gwdt->base + FTWDT010_WDCR);
>  	}
>  
> -	ret = devm_request_irq(dev, irq, ftwdt010_wdt_interrupt, 0,
> -			       "watchdog bark", gwdt);
> -	if (ret)
> -		return ret;
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq) {
> +		ret = devm_request_irq(dev, irq, ftwdt010_wdt_interrupt, 0,
> +				       "watchdog bark", gwdt);
> +		if (ret)
> +			return ret;
> +		gwdt->has_irq = true;
> +	}
>  
>  	ret = devm_watchdog_register_device(dev, &gwdt->wdd);
>  	if (ret) {