Hi,

Looks like this wasn't merged.  Any thoughts on doing so?

On Wed, Jun 09, 2010 at 11:39:42AM +0200, Marek Szyprowski wrote:
> S3C SDHCI host controller can change the source for generating mmc clock.
> By default host bus clock is used, what causes some problems on machines
> with 133MHz bus, because the SDHCI divider cannot be as high get proper
> clock value for identification mode. This is not a problem for the
> controller, because it can generate lower frequencies from other clock
> sources. This patch adds a new quirk to SDHCI driver to calculate the
> minimal supported clock frequency.
> 
> This fixes the flood of the following warnings on Samsung S5PV210 SoCs:
> mmc0: Minimum clock frequency too high for identification mode
> 
> Signed-off-by: Marek Szyprowski <m.szyprow...@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.p...@samsung.com>
> ---
>  drivers/mmc/host/sdhci-of-esdhc.c |    1 +
>  drivers/mmc/host/sdhci-s3c.c      |   29 +++++++++++++++++++++++++++++
>  drivers/mmc/host/sdhci.c          |    2 +-
>  drivers/mmc/host/sdhci.h          |    2 ++
>  4 files changed, 33 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-of-esdhc.c 
> b/drivers/mmc/host/sdhci-of-esdhc.c
> index c8623de..64b3f79 100644
> --- a/drivers/mmc/host/sdhci-of-esdhc.c
> +++ b/drivers/mmc/host/sdhci-of-esdhc.c
> @@ -124,6 +124,7 @@ struct sdhci_of_data sdhci_esdhc = {
>                 SDHCI_QUIRK_BROKEN_CARD_DETECTION |
>                 SDHCI_QUIRK_NO_BUSY_IRQ |
>                 SDHCI_QUIRK_NONSTANDARD_CLOCK |
> +               SDHCI_QUIRK_NONSTANDARD_MINCLOCK |
>                 SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
>                 SDHCI_QUIRK_PIO_NEEDS_DELAY |
>                 SDHCI_QUIRK_RESTORE_IRQS_AFTER_RESET |
> diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
> index 2b6cb44..615008d 100644
> --- a/drivers/mmc/host/sdhci-s3c.c
> +++ b/drivers/mmc/host/sdhci-s3c.c
> @@ -209,10 +209,37 @@ static void sdhci_s3c_set_clock(struct sdhci_host 
> *host, unsigned int clock)
>       }
>  }
>  
> +/**
> + * sdhci_s3c_get_min_clock - callback to get minimal supported clock value
> + * @host: The SDHCI host being queried
> + *
> + * To init mmc host properly a minimal clock value is needed. For high system
> + * bus clock's values the standard formula gives values out of allowed range.
> + * The clock still can be set to lower values, if clock source other then
> + * system bus is selected.
> +*/
> +static unsigned int sdhci_s3c_get_min_clock(struct sdhci_host *host)
> +{
> +     struct sdhci_s3c *ourhost = to_s3c(host);
> +     unsigned int delta, min = UINT_MAX;
> +     int src;
> +
> +     for (src = 0; src < MAX_BUS_CLK; src++) {
> +             delta = sdhci_s3c_consider_clock(ourhost, src, 0);
> +             if (delta == UINT_MAX)
> +                     continue;
> +             /* delta is a negative value in this case */
> +             if (-delta < min)
> +                     min = -delta;
> +     }
> +     return min;
> +}
> +
>  static struct sdhci_ops sdhci_s3c_ops = {
>       .get_max_clock          = sdhci_s3c_get_max_clk,
>       .get_timeout_clock      = sdhci_s3c_get_timeout_clk,
>       .set_clock              = sdhci_s3c_set_clock,
> +     .get_min_clock          = sdhci_s3c_get_min_clock,
>  };
>  
>  static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
> @@ -316,6 +343,8 @@ static int __devinit sdhci_s3c_probe(struct 
> platform_device *pdev)
>       host->quirks = 0;
>       host->irq = irq;
>  
> +     host->quirks |= SDHCI_QUIRK_NONSTANDARD_MINCLOCK;
> +
>       /* Setup quirks for the controller */
>       host->quirks |= SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC;
>  
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index c6d1bd8..8b3ee53 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1785,7 +1785,7 @@ int sdhci_add_host(struct sdhci_host *host)
>        * Set host parameters.
>        */
>       mmc->ops = &sdhci_ops;
> -     if (host->quirks & SDHCI_QUIRK_NONSTANDARD_CLOCK &&
> +     if (host->quirks & SDHCI_QUIRK_NONSTANDARD_MINCLOCK &&
>                       host->ops->set_clock && host->ops->get_min_clock)
>               mmc->f_min = host->ops->get_min_clock(host);
>       else
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index c846813..3fd87c2 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -240,6 +240,8 @@ struct sdhci_host {
>  #define SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN            (1<<25)
>  /* Controller cannot support End Attribute in NOP ADMA descriptor */
>  #define SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC            (1<<26)
> +/* Controller has nonstandard clock management */
> +#define SDHCI_QUIRK_NONSTANDARD_MINCLOCK             (1<<27)
>  
>       int                     irq;            /* Device IRQ */
>       void __iomem *          ioaddr;         /* Mapped address */
> -- 
> 1.7.1.240.g225c

-- 
Chris Ball   <c...@laptop.org>   <http://printf.net/>
One Laptop Per Child
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