Re: [RFC PATCH v3.1 14/27] mmc: sdhci-uhs2: skip signal_voltage_switch()

AKASHI Takahiro
2020-11-30T07:39:07Z

On Thu, Nov 26, 2020 at 10:16:44AM +0200, Adrian Hunter wrote:
> On 6/11/20 4:27 am, AKASHI Takahiro wrote:
> > For UHS2, the signal voltage is supplied by vdd2 which is already 1.8v,
> > so no voltage switch required.
> >
> > Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > ---
> > drivers/mmc/host/sdhci-uhs2.c | 26 ++++++++++++++++++++++++++
> > 1 file changed, 26 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
> > index 2bf78cc4e9ed..1eca89359351 100644
> > --- a/drivers/mmc/host/sdhci-uhs2.c
> > +++ b/drivers/mmc/host/sdhci-uhs2.c
> > @@ -178,6 +178,29 @@ void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode,
> > }
> > EXPORT_SYMBOL_GPL(sdhci_uhs2_set_power);
> >
> > +/*****************************************************************************\
> > + * *
> > + * MMC callbacks *
> > + * *
> > +\*****************************************************************************/
> > +
> > +static int sdhci_uhs2_start_signal_voltage_switch(struct mmc_host *mmc,
> > + struct mmc_ios *ios)
> > +{
> > + struct sdhci_host *host = mmc_priv(mmc);
> > +
> > + /*
> > + * For UHS2, the signal voltage is supplied by vdd2 which is
> > + * already 1.8v so no voltage switch required.
> > + */
> > + if (IS_ENABLED(CONFIG_MMC_SDHCI_UHS2) &&
> > + host->version >= SDHCI_SPEC_400 &&
> > + host->mmc->flags & MMC_UHS2_SUPPORT)
>
> Could this be the same helper function suggested elsewhere i.e.
>
> if (!sdhci_uhs2_mode(host))

ditto. I'd defer the change until some time later.

-Takahiro Akashi

>
> > + return 0;
> > +
> > + return sdhci_start_signal_voltage_switch(mmc, ios);
> > +}
> > +
> > /*****************************************************************************\
> > * *
> > * Driver init/exit *
> > @@ -186,6 +209,9 @@ EXPORT_SYMBOL_GPL(sdhci_uhs2_set_power);
> >
> > static int sdhci_uhs2_host_ops_init(struct sdhci_host *host)
> > {
> > + host->mmc_host_ops.start_signal_voltage_switch =
> > + sdhci_uhs2_start_signal_voltage_switch;
> > +
> > return 0;
> > }
> >
> >
>