[PATCH v4 9/9] mmc: dw_mmc: add support for exynos specific implementation of dw-mshc

[Thomas Abraham]

On 28 August 2012 10:25, Jaehoon Chung <jh80.chung at samsung.com> wrote:
> Hi Thomas,
>
> On 08/28/2012 01:48 PM, Thomas Abraham wrote:
>> On 27 August 2012 14:28, Jaehoon Chung <jh80.chung at samsung.com> wrote:
>>> Hi Thomas,
>>>
>>>> +     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 {
>>>> +             dev_info(host->dev, "wp gpio not available");
>>>> +             host->pdata->quirks |= DW_MCI_QUIRK_NO_WRITE_PROTECT;
>>>> +     }
>>>> +
>>>> +     if (host->pdata->quirks & DW_MCI_QUIRK_BROKEN_CARD_DETECTION)
>>>> +             return 0;
>>>> +
>>>> +     gpio = of_get_named_gpio(slot_np, "samsung,cd-pinmux-gpio", 0);
>>>> +     if (gpio_is_valid(gpio)) {
>>>> +             if (devm_gpio_request(host->dev, gpio, "dw-mci-cd"))
>>> I'm not sure, but i saw mmc_gpio_request_cd() into drivers/mmc/core/slot-gpio.c.
>>> Can we use this? i think we can use them.
>>> Just my opinion.
>>
>> Thanks for letting me know about this, I was not aware of this.
>> Looking into this code, it is usable for controllers that use a gpio
>> (specified using cd-gpios property) as card-detect line. As you know,
>> the dw-mmc driver does not support this feature yet. In case of
>> exynos, the card-detect pin of the mmc slot is connected to the
>> card-detect pad of the dw-mmc controller using pinmux, which is not
>> considered as a gpio. Hence, mmc_gpio_request_cd() is not applicable
>> in this case.
> But In case of external card-detect-pin, we can use the mmc_gpio_request_cd().

Yes, we can use. But the current dw-mmc controller driver does not
support this feature yet. The existing driver considers that (a)
card-detect line is connected to the card-detect pad of the controller
or (b) it is broken. For Exynos5250, it is case (a). There is no
support for using a gpio as an card-detect line.

Thanks,
Thomas.