[PATCH 2/3] mmc: esdhc i.MX: Fix version register read

[Shawn Guo]

On Mon, Sep 24, 2012 at 09:22:24AM +0200, Sascha Hauer wrote:
> The i.MX ESDHC controller version register is a mess:
> 
> - i.MX25 has a v1 controller which identifies itself as v2
> - i.MX6Q has a v3 controller which identifies itself as v4
> - i.MX35,51,53 have v2 controllers which identify themselves correctly
> 
> Additionally on i.MX the register is located at offset 0xfc instead of
> 0xfe. The i.MX6 had a quirk around it which converted v4 into v3. Instead

Ah, I added the quirk for i.MX6 without noticing that other SoCs have
the similar problem.

> of reading the real version register, all other SoCs used to return
> the value from 0xfe which contains 0x0 for all SoCs, so all controllers
> except i.MX6q were identified as version v1.
> 
> This patch fixes this by returning the version based on the devtype
> data leaving the useless version register untouched.
> 
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>

Acked-by: Shawn Guo <shawn.guo at linaro.org>

> ---
>  drivers/mmc/host/sdhci-esdhc-imx.c |   21 +++++++++++++--------
>  1 file changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index e23f813..4fe7312 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -237,15 +237,20 @@ static void esdhc_writel_le(struct sdhci_host *host, u32 val, int reg)
>  
>  static u16 esdhc_readw_le(struct sdhci_host *host, int reg)
>  {
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct pltfm_imx_data *imx_data = pltfm_host->priv;
> +
>  	if (unlikely(reg == SDHCI_HOST_VERSION)) {
> -		u16 val = readw(host->ioaddr + (reg ^ 2));
> -		/*
> -		 * uSDHC supports SDHCI v3.0, but it's encoded as value
> -		 * 0x3 in host controller version register, which violates
> -		 * SDHCI_SPEC_300 definition.  Work it around here.
> -		 */
> -		if ((val & SDHCI_SPEC_VER_MASK) == 3)
> -			return --val;
> +		switch (imx_data->devtype) {
> +		case IMX25_ESDHC:
> +			return SDHCI_SPEC_100;
> +		case IMX35_ESDHC:
> +		case IMX51_ESDHC:
> +		case IMX53_ESDHC:
> +			return SDHCI_SPEC_200;
> +		case IMX6Q_USDHC:
> +			return SDHCI_SPEC_300;
> +		}
>  	}
>  
>  	return readw(host->ioaddr + reg);
> -- 
> 1.7.10.4
> 
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