From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Subject: Re: [PATCH] Revert "sdhci-of-esdhc: Support 8BIT bus width."
Date: Fri, 15 May 2015 08:00:54 +0000
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On Fri, 2015-05-15 at 15:42 +0800, Kevin Hao wrote:
> On Fri, May 15, 2015 at 07:24:55AM +0000, Joakim Tjernlund wrote:
> > Ahh, now I see. Drivers are supposed to call sdhci_set_bus_width instead of NULL:
> > Instead of reverting this add:
> > 
> >  diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
> > index 7a98a22..07b9df2 100644
> > --- a/drivers/mmc/host/sdhci-of-esdhc.c
> > +++ b/drivers/mmc/host/sdhci-of-esdhc.c
> > @@ -283,6 +283,7 @@ static const struct sdhci_ops sdhci_esdhc_ops = {
> >         .get_min_clock = esdhc_of_get_min_clock,
> >         .platform_init = esdhc_of_platform_init,
> >         .adma_workaround = esdhci_of_adma_workaround,
> > +       .set_bus_width = sdhci_set_bus_width,
> >         .reset = esdhc_reset,
> >         .set_uhs_signaling = sdhci_set_uhs_signaling,
> >  };
> > 
> > Should I repost the full "sdhci-of-esdhc: Support 8BIT bus width." with this fix added
> > of just the above fix?
> 
> Sorry, this still don't work.

hmm, looking at
sdhci_set_bus_width(struct sdhci_host *host, int width)
{
        u8 ctrl;

        ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
        if (width == MMC_BUS_WIDTH_8) {
                ctrl &= ~SDHCI_CTRL_4BITBUS;
                if (host->version >= SDHCI_SPEC_300)
                        ctrl |= SDHCI_CTRL_8BITBUS;

I suspect SDHCI_SPEC_300 is not set for you? I see that 
sdhci-esdhc-imx.c has:
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;
        u16 ret = 0;
        u32 val;

        if (unlikely(reg == SDHCI_HOST_VERSION)) {
                reg ^= 2;
                if (esdhc_is_usdhc(imx_data)) {
                        /*
                         * The usdhc register returns a wrong host version.
                         * Correct it here.
                         */
                        return SDHCI_SPEC_300;
                }

so I am guessing that our driver needs either needs something similar or
just an own impl of sdhci_set_bus_width:

void sdhci_set_bus_width(struct sdhci_host *host, int width)
{
        u8 ctrl;

        ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
        if (width == MMC_BUS_WIDTH_8) {
                ctrl &= ~SDHCI_CTRL_4BITBUS;
                ctrl |= SDHCI_CTRL_8BITBUS;
        } else {
                ctrl &= ~SDHCI_CTRL_8BITBUS;
                if (width == MMC_BUS_WIDTH_4)
                        ctrl |= SDHCI_CTRL_4BITBUS;
                else
                        ctrl &= ~SDHCI_CTRL_4BITBUS;
        }
        sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
}

 Jocke