Re: [PATCH RESEND v7 2/2] mmc: host: sdhci: Add support to disable SDR104/SDR50/DDR50 based on capability register 0.

Dong Aisheng
2015-06-05T14:53:26Z

On Mon, Jun 01, 2015 at 01:38:47PM +0530, Suman Tripathi wrote:
> Hi Aisheng,
> On Wed, May 27, 2015 at 7:46 PM, Suman Tripathi <[1]stripathi@apm.com>
> wrote:
>
> On Tue, May 26, 2015 at 6:06 PM, Ulf Hansson <[2]ulf.hansson@linaro.org>
> wrote:
>
> On 21 May 2015 at 10:43, Suman Tripathi <[3]stripathi@apm.com> wrote:
> > The sdhci framework disables SDR104/SDR50/DDR50 based on only quirk.
> > This patch adds the support to disable SDR104/SDR50/DDR50 based on
> > reading the capability register 0.
> >
> > Signed-off-by: Suman Tripathi <[4]stripathi@apm.com>
> > ---
> > ---
> > drivers/mmc/host/sdhci.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> > index 58c1770..a3d9b8a 100644
> > --- a/drivers/mmc/host/sdhci.c
> > +++ b/drivers/mmc/host/sdhci.c
> > @@ -3118,7 +3118,8 @@ int sdhci_add_host(struct sdhci_host *host)
> > }
> > }
> >
> > - if (host->quirks2 & SDHCI_QUIRK2_NO_1_8_V)
> > + if (host->quirks2 & SDHCI_QUIRK2_NO_1_8_V ||
> > + !(caps[0] & SDHCI_CAN_VDD_180))
> > caps[1] &= ~(SDHCI_SUPPORT_SDR104 |
> SDHCI_SUPPORT_SDR50 |
> > SDHCI_SUPPORT_DDR50);
> >
> > --
> > 1.8.2.1
> >
>
> I have no problem with this patch, except that it would be nice to get
> a few "tested by" to make sure it doesn't break UHS support for some
> SoCs.
>
> Kind regards
> Uffe
>
> Can anyone test this in some other SoC ? Appreciate your help ..
>
> Can you test this patch on imx SoC ?
>

(Your email have some format issue.)

I have tested this patch and it does not break imx SoC.
You can add my tag.
Tested-by: Dong Aisheng <aisheng.dong@freescale.com>

However, it looks to me SDHCI_CAN_VDD_180 is only indicating the host VDD
capabiliies, not IO voltage capability.
SD3.0 cards require 1.8v IO voltage support.
So should this bit affect SD3.0 support?
e.g. some hosts can only work at VDD_330 (most VDD of SD slot on IMX boards
is using external regulator and is fixed to 3.3v), but it can support 1.8v
IO voltage, so it can support SD3.0 cards as well.

Ulf,
Can you help confirm it?

Regards
Dong Aisheng

> --
> Thanks,
> with regards,
> Suman Tripathi
>
> --
> Thanks,
> with regards,
> Suman Tripathi
>
> References
>
> Visible links
> 1. mailto:stripathi@apm.com
> 2. mailto:ulf.hansson@linaro.org
> 3. mailto:stripathi@apm.com
> 4. mailto:stripathi@apm.com
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> are supported and installed on your system.
> perl: warning: Falling back to the standard locale ("C").