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.

Thanks
Chuanxiao
> +
> +     spin_unlock_irqrestore(&host->lock, flags);
> +
> +     return (present & (SDHCI_CARD_PRESENT | SDHCI_CARD_CDPL));
> +}
> +
>  static void sdhci_enable_sdio_irq_nolock(struct sdhci_host *host, int enable)
>  {
>       if (host->flags & SDHCI_DEVICE_DEAD)
> @@ -1884,6 +1903,7 @@ static const struct mmc_host_ops sdhci_ops = {
>       .request        = sdhci_request,
>       .set_ios        = sdhci_set_ios,
>       .get_ro         = sdhci_get_ro,
> +     .get_cd         = sdhci_get_cd,
>       .hw_reset       = sdhci_hw_reset,
>       .enable_sdio_irq = sdhci_enable_sdio_irq,
>       .start_signal_voltage_switch    = sdhci_start_signal_voltage_switch,
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 0a5b654..8ea7e00 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -69,6 +69,7 @@
>  #define  SDHCI_SPACE_AVAILABLE       0x00000400
>  #define  SDHCI_DATA_AVAILABLE        0x00000800
>  #define  SDHCI_CARD_PRESENT  0x00010000
> +#define  SDHCI_CARD_CDPL     0x00040000
>  #define  SDHCI_WRITE_PROTECT 0x00080000
>  #define  SDHCI_DATA_LVL_MASK 0x00F00000
>  #define   SDHCI_DATA_LVL_SHIFT       20
> --
> 1.7.5.4
> 
> 
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