linux-kernel - RE: [PATCH v2 1/2] mmc: dw_mmc: exynos: Stop claiming wp-gpio

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Message-id: <001a01cdcd4a$cf01ad40$6d0507c0$%jun@samsung.com>
Date:	Wed, 28 Nov 2012 18:29:04 +0900
From:	Seungwon Jeon <tgih.jun@...sung.com>
To:	'Doug Anderson' <dianders@...omium.org>,
	linux-samsung-soc@...r.kernel.org,
	'Thomas Abraham' <thomas.abraham@...aro.org>,
	'Kukjin Kim' <kgene.kim@...sung.com>
Cc:	'Olof Johansson' <olof@...om.net>, 'Arnd Bergmann' <arnd@...db.de>,
	'Will Newton' <will.newton@...tec.com>,
	'Chris Ball' <cjb@...top.org>,
	'Jaehoon Chung' <jh80.chung@...sung.com>,
	linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: RE: [PATCH v2 1/2] mmc: dw_mmc: exynos: Stop claiming wp-gpio

Yes. pin of write protection is common property.
This change is good. I have some suggestion below.
Could you check it?

On Friday, November 23, 2012, Doug Anderson wrote:
> The exynos code claimed wp-gpio with devm_gpio_request() but never did
> anything with it.  That meant that anyone using a write protect GPIO
> would effectively be write protected all the time.
> 
> A future change will move the wp-gpio support to the core dw_mmc.c
> file.  Now the exynos-specific code won't claim the GPIO but will
> just set the DW_MCI_QUIRK_NO_WRITE_PROTECT quirk if write protect
> won't be used.
> 
> Signed-off-by: Doug Anderson <dianders@...omium.org>
> 
> ---
> Changes in v2:
> - Nothing new in this patch
> 
>  drivers/mmc/host/dw_mmc-exynos.c |   12 ++++++------
>  1 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
> index 4d50da6..58cc03e 100644
> --- a/drivers/mmc/host/dw_mmc-exynos.c
> +++ b/drivers/mmc/host/dw_mmc-exynos.c
> @@ -175,12 +175,12 @@ static int dw_mci_exynos_setup_bus(struct dw_mci *host,
>  		}
>  	}
> 
> -	gpio = of_get_named_gpio(slot_np, "wp-gpios", 0);
> -	if (gpio_is_valid(gpio)) {
> -		if (devm_gpio_request(host->dev, gpio, "dw-mci-wp"))
> -			dev_info(host->dev, "gpio [%d] request failed\n",
> -						gpio);
> -	} else {
> +	/*
> +	 * If there are no write-protect GPIOs present then we assume no write
> +	 * protect.  The mci_readl() in dw_mmc.c won't work since it's not
> +	 * hooked up on exynos.
> +	 */
> +	if (!of_find_property(slot_np, "wp-gpios", NULL)) {
>  		dev_info(host->dev, "wp gpio not available");
>  		host->pdata->quirks |= DW_MCI_QUIRK_NO_WRITE_PROTECT;
>  	}
All card types need this quirk in case wp-gpio property is empty?
I think wp-pin is valid for SD card, not eMMC/SDIO.
Of course, I know origin code did it.
How about removing whole checking routine?
Instead, new definition for this quirk can be added into 'dw_mci_of_quirks'(dw_mmc.c) and dts file.

Thanks,
Seungwon Jeon
> --
> 1.7.7.3

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