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

Yong Ding
2012-10-18T06:27:17Z

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@linaro.org]
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@vger.kernel.org; linux-kernel@vger.kernel.org
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.
>