From mboxrd@z Thu Jan  1 00:00:00 1970
From: u.kleine-koenig@pengutronix.de (Uwe =?iso-8859-1?Q?Kleine-K=F6nig?=)
Date: Wed, 14 Sep 2011 08:55:02 +0200
Subject: [PATCH] ARM: mach-mxs/mx28evk: Only register devices if their
	GPIO requests succeeded
In-Reply-To: <1315945519-15178-1-git-send-email-festevam@gmail.com>
References: <1315945519-15178-1-git-send-email-festevam@gmail.com>
Message-ID: <20110914065501.GR28624@pengutronix.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Hello,

On Tue, Sep 13, 2011 at 05:25:19PM -0300, Fabio Estevam wrote:
> Currently framebuffer and MMC devices are registered even if their associated 
> GPIO pins fail to be requested.
Is this a real or only theoretic problem? (For me (or later Sascha) to
judge if it should go in before 3.2.)

> diff --git a/arch/arm/mach-mxs/mach-mx28evk.c b/arch/arm/mach-mxs/mach-mx28evk.c
> index 3f86e7a..e5c66a2 100644
> --- a/arch/arm/mach-mxs/mach-mx28evk.c
> +++ b/arch/arm/mach-mxs/mach-mx28evk.c
> @@ -353,7 +353,7 @@ static struct mxs_mmc_platform_data mx28evk_mmc_pdata[] __initdata = {
>  
>  static void __init mx28evk_init(void)
>  {
> -	int ret;
> +	int ret, gpio_lcd_error;
>  
>  	mxs_iomux_setup_multiple_pads(mx28evk_pads, ARRAY_SIZE(mx28evk_pads));
>  
> @@ -378,18 +378,23 @@ static void __init mx28evk_init(void)
>  	}
>  
>  	ret = gpio_request_one(MX28EVK_LCD_ENABLE, GPIOF_DIR_OUT, "lcd-enable");
> -	if (ret)
> +	if (ret) {
>  		pr_warn("failed to request gpio lcd-enable: %d\n", ret);
> +		gpio_lcd_error = 1;
> +	}
>  	else
>  		gpio_set_value(MX28EVK_LCD_ENABLE, 1);
>  
>  	ret = gpio_request_one(MX28EVK_BL_ENABLE, GPIOF_DIR_OUT, "bl-enable");
> -	if (ret)
> +	if (ret) {
>  		pr_warn("failed to request gpio bl-enable: %d\n", ret);
> +		gpio_lcd_error = 1;
> +	}
>  	else
>  		gpio_set_value(MX28EVK_BL_ENABLE, 1);
If it's not important which gpio failed, you can do:

	ret = gpio_request_array(...)
	if (ret)
		pr_warn("failed to request gpio for lcd\n");
	else
		mx28_add_mxsfb(&mx28evk_mxsfb_pdata);

(Apart from the different message this differs in semantic when the 2nd
request fails. With my suggestion the first gpio is freed then which
seems cleaner.) I don't care much though.
		
> -	mx28_add_mxsfb(&mx28evk_mxsfb_pdata);
> +	if (!gpio_lcd_error)
> +		mx28_add_mxsfb(&mx28evk_mxsfb_pdata);
>  
>  	/* power on mmc slot by writing 0 to the gpio */
>  	ret = gpio_request_one(MX28EVK_MMC0_SLOT_POWER, GPIOF_OUT_INIT_LOW,
> @@ -402,8 +407,9 @@ static void __init mx28evk_init(void)
>  			       "mmc1-slot-power");
>  	if (ret)
>  		pr_warn("failed to request gpio mmc1-slot-power: %d\n", ret);
> -	mx28_add_mxs_mmc(1, &mx28evk_mmc_pdata[1]);
> -
> +	else
> +		mx28_add_mxs_mmc(1, &mx28evk_mmc_pdata[1]);
> +
>  	gpio_led_register_device(0, &mx28evk_led_data);
>  }

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |