Hi, Chuanxiao > -----Original Message----- > From: linux-mmc-ow...@vger.kernel.org [mailto:linux-mmc- > ow...@vger.kernel.org] On Behalf Of Dong, Chuanxiao > Sent: Monday, December 05, 2011 7:25 PM > To: Huang Changming-R66093; linux-mmc@vger.kernel.org > Cc: Huang Changming-R66093 > Subject: RE: [PATCH 1/4] SDHCI: add sdhci_get_cd callback to detect the > card > > Hi Jerry, > > > -----Original Message----- > > From: linux-mmc-ow...@vger.kernel.org > > [mailto:linux-mmc-ow...@vger.kernel.org] On Behalf Of > > r66...@freescale.com > > Sent: Monday, December 05, 2011 5:24 PM > > To: linux-mmc@vger.kernel.org > > Cc: Jerry Huang > > Subject: [PATCH 1/4] SDHCI: add sdhci_get_cd callback to detect the > > card > > > > From: Jerry Huang <chang-ming.hu...@freescale.com> > > > > Add callback function sdhci_get_cd to detect the card. > > In order to check if the card is present, we will read the PRESENT > > STATE register and check the bit13(Card detect pin level) and > bit15(CINS). > > > > Signed-off-by: Jerry Huang <chang-ming.hu...@freescale.com> > > --- > > drivers/mmc/host/sdhci.c | 20 ++++++++++++++++++++ > > drivers/mmc/host/sdhci.h | 1 + > > 2 files changed, 21 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index > > 6d8eea3..66afd82 100644 > > --- a/drivers/mmc/host/sdhci.c > > +++ b/drivers/mmc/host/sdhci.c > > @@ -2,6 +2,7 @@ > > * linux/drivers/mmc/host/sdhci.c - Secure Digital Host Controller > > Interface driver > > * > > * Copyright (C) 2005-2008 Pierre Ossman, All Rights Reserved. > > + * Copyright (C) 2011 Freescale Semiconductor Inc. > > * > > * This program is free software; you can redistribute it and/or > modify > > * it under the terms of the GNU General Public License as published > > by @@ -1518,6 +1519,24 @@ static int sdhci_get_ro(struct mmc_host *mmc) > > return ret; > > } > > > > +static int sdhci_get_cd(struct mmc_host *mmc) { > > + struct sdhci_host *host = mmc_priv(mmc); > > + unsigned long flags; > > + int present; > > + > > + spin_lock_irqsave(&host->lock, flags); > > + > > + if (host->flags & SDHCI_DEVICE_DEAD) > > + present = 0; > > + else > > + present = sdhci_readl(host, SDHCI_PRESENT_STATE); > > As far as I know, some SDHC host controller didn't implement its present > register well...The present register of some SDHC host controller will > report "there is a card" forever. So, according to your patch2, using > such method is not a proper solution for card detection, I think. Yes, maybe some controller don't support this feature, maybe can add one callback function to the platform special code. But, we need to define this interface.
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