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Message-ID: <511DAC56.8080404@marvell.com>
Date: Fri, 15 Feb 2013 11:32:38 +0800
From: Qing Xu <qingx@marvell.com>
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To: Arnd Bergmann <arnd@arndb.de>
Cc: "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Haojian Zhuang <haojian.zhuang@gmail.com>,
        Samuel Ortiz <sameo@linux.intel.com>
Subject: Re: [PATCH 4/9] mfd: max8925: fix trivial build warning for non-dt
References: <1360880818-4071454-1-git-send-email-arnd@arndb.de> <1360880818-4071454-5-git-send-email-arnd@arndb.de>
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On 02/15/2013 06:26 AM, Arnd Bergmann wrote:
> Patch fe527ea5a "mfd: max8925: Support dt for backlight"
> added a new function for DT probing but introduced a
> build warning for the case where CONFIG_OF is disabled:
>
> drivers/video/backlight/max8925_bl.c: In function 'max8925_backlight_probe':
> drivers/video/backlight/max8925_bl.c:177:3: warning: statement with no effect [-Wunused-value]
>
> A much nicer fix is to use the IS_ENABLED keyword to
> have the same effect of dropping the device tree specific
> function when it's not needed.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Cc: Qing Xu <qingx@marvell.com>
> Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
> Cc: Samuel Ortiz <sameo@linux.intel.com>
> ---
>   drivers/video/backlight/max8925_bl.c | 6 +-----
>   1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/drivers/video/backlight/max8925_bl.c b/drivers/video/backlight/max8925_bl.c
> index 5ca11b0..9958fb1 100644
> --- a/drivers/video/backlight/max8925_bl.c
> +++ b/drivers/video/backlight/max8925_bl.c
> @@ -101,14 +101,13 @@ static const struct backlight_ops max8925_backlight_ops = {
>   	.get_brightness	= max8925_backlight_get_brightness,
>   };
>   
> -#ifdef CONFIG_OF
>   static int max8925_backlight_dt_init(struct platform_device *pdev,
>   			      struct max8925_backlight_pdata *pdata)
>   {
>   	struct device_node *nproot = pdev->dev.parent->of_node, *np;
>   	int dual_string;
>   
> -	if (!nproot)
> +	if (!nproot || !IS_ENABLED(CONFIG_OF))
>   		return -ENODEV;
>   	np = of_find_node_by_name(nproot, "backlight");
>   	if (!np) {
> @@ -120,9 +119,6 @@ static int max8925_backlight_dt_init(struct platform_device *pdev,
>   	pdata->dual_string = dual_string;
>   	return 0;
>   }
> -#else
> -#define max8925_backlight_dt_init(x, y)	(-1)
> -#endif
>   
>   static int max8925_backlight_probe(struct platform_device *pdev)
>   {

thanks, I am ok with the change.