RE: [PATCH 1/3] mmc: esdhc: enable polling to detect card by itself

[Yong Ding]

Shawn,
Thanks. Oh, sorry I really have missed the fact u mentioned. U are right in the current code, the bit will also be cleared for ESDHC_CD_GPIO. 
But I think this is improper since for GPIO detection type, we don't use the host controller internal card detection(ESDHC_CD_CONTROLLER), but with SDHCI_QUIRK_BROKEN_CARD_DETECTION cleared, we'll still enable/disable relevant INT bits (in sdhci_set_card_detection in sdhci.c). This is my biggest concern. And I think the SDHCI_QUIRK_BROKEN_CARD_DETECTION shall be purely used to notify whether the host controller detection method is used or not. So even for the ESDHC_CD_GPIO type, we should still set this flag. How do u think?

-----Original Message-----
From: Shawn Guo [mailto:shawn.guo@xxxxxxxxxx] 
Sent: 2012年10月18日 13:51
To: Yong Ding
Cc: Chris Ball; Anton Vorontsov; Marek Szyprowski; Wolfram Sang; Daniel Drake; Sascha Hauer; Wilson Callan; Ben Dooks; Zhangfei Gao; Kevin Liu; Jialing Fu; linux-mmc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: [PATCH 1/3] mmc: esdhc: enable polling to detect card by itself

On Tue, Oct 16, 2012 at 09:01:40PM -0700, Yong Ding wrote:
> Shawn,
> Thanks for your comment. And sorry for my so late due to illness:-)
> SDHCI_QUIRK_BROKEN_CARD_DETECTION is used for notifying we don't use the host internal card detection method so that we don't need enable/disable those relevant interrupt bits of host(sdhci_set_card_detection in sdhci.c). 
> And as I double-checked the latest kernel code, actually sdhci-esdhc-imx sets this flag by default, and then will clear it only when the detection type is ESDHC_CD_CONTROLLER. So this aligns with my understanding. 

What I was saying is the bit will be cleared when the detection type is
ESDHC_CD_CONTROLLE or ESDHC_CD_GPIO.  You may have missed the fact that
there is no "break" in case ESDHC_CD_GPIO but a "fall through" comment.

        switch (boarddata->cd_type) {
        case ESDHC_CD_GPIO:
                err = gpio_request_one(boarddata->cd_gpio, GPIOF_IN, "ESDHC_CD");
                if (err) {
                        dev_err(mmc_dev(host->mmc),
                                "no card-detect pin available!\n");
                        goto no_card_detect_pin;
                }

                err = request_irq(gpio_to_irq(boarddata->cd_gpio), cd_irq,
                                 IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
                                 mmc_hostname(host->mmc), host);
                if (err) {
                        dev_err(mmc_dev(host->mmc), "request irq error\n");
                        goto no_card_detect_irq;
                }
                /* fall through */

        case ESDHC_CD_CONTROLLER:
                /* we have a working card_detect back */
                host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
                break;

        case ESDHC_CD_PERMANENT:
                host->mmc->caps = MMC_CAP_NONREMOVABLE;
                break;

        case ESDHC_CD_NONE:
                break;
        }

Shawn

> What I want to do is that 1st we shall set MMC_CAP_NEEDS_POLL by our host driver itself and 2nd remove the improper logic in sdhci_add_host() . How do u think? Thanks.
> 
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