[PATCH v2 2/7] mmc: sdhci-of-k1: add regulator and pinctrl voltage switching support

[Iker Pedrosa]

El lun, 9 mar 2026 a las 14:22, Yixun Lan (<dlan at kernel.org>) escribió:
>
> Hi Iker,
>
> On 12:40 Mon 09 Mar     , Iker Pedrosa wrote:
> > Add voltage switching infrastructure for UHS-I modes by integrating both
> > regulator framework (for supply voltage control) and pinctrl state
> > switching (for pin drive strength optimization).
> >
> > - Add regulator supply parsing and voltage switching callback
> > - Add optional pinctrl state switching between "default" (3.3V) and
> >   "state_uhs" (1.8V) configurations
> > - Enable coordinated voltage and pin configuration changes for UHS modes
> >
> > This provides complete voltage switching support while maintaining
> > backward compatibility when pinctrl states are not defined.
> >
> > Signed-off-by: Iker Pedrosa <ikerpedrosam at gmail.com>
> > ---
> >  drivers/mmc/host/sdhci-of-k1.c | 59 ++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 59 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
> > index 585c7eca6ebf253aac466dd37cef029deb63f692..8af117a8e271c04a80d8dc7bb5ce12075652dd7a 100644
> > --- a/drivers/mmc/host/sdhci-of-k1.c
> > +++ b/drivers/mmc/host/sdhci-of-k1.c
> > @@ -15,6 +15,7 @@
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/of_device.h>
> > +#include <linux/pinctrl/consumer.h>
> >  #include <linux/platform_device.h>
> >
> >  #include "sdhci.h"
> > @@ -70,6 +71,9 @@
> >  struct spacemit_sdhci_host {
> >       struct clk *clk_core;
> >       struct clk *clk_io;
> > +     struct pinctrl *pinctrl;
> > +     struct pinctrl_state *pinctrl_default;
> > +     struct pinctrl_state *pinctrl_uhs;
> >  };
> >
> >  /* All helper functions will update clr/set while preserve rest bits */
> > @@ -218,6 +222,42 @@ static void spacemit_sdhci_pre_hs400_to_hs200(struct mmc_host *mmc)
> >                              SPACEMIT_SDHC_PHY_CTRL_REG);
> >  }
> >
> > +static void spacemit_sdhci_voltage_switch(struct sdhci_host *host)
> > +{
> > +     struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> > +     struct spacemit_sdhci_host *sdhst = sdhci_pltfm_priv(pltfm_host);
> > +     struct mmc_ios *ios = &host->mmc->ios;
> > +     struct pinctrl_state *state;
> > +     int ret;
> > +
> > +     /* Select appropriate pinctrl state based on signal voltage */
> > +     if (sdhst->pinctrl) {
> do a sanity check, then abort it early, the advantage is that you can get rid of
> one indetation for next code..
>
>         if (!sdhst->pinctrl)
>                 return;
>

Makes sense. I'll get it ready for the next version.

>
> > +             switch (ios->signal_voltage) {
> > +             case MMC_SIGNAL_VOLTAGE_330:
> > +                     state = sdhst->pinctrl_default;
> > +                     break;
> > +             case MMC_SIGNAL_VOLTAGE_180:
> > +                     state = sdhst->pinctrl_uhs;
> > +                     break;
> > +             default:
> > +                     dev_warn(mmc_dev(host->mmc), "unsupported voltage %d\n",
> > +                              ios->signal_voltage);
> > +                     return;
> > +             }
> > +
> > +             if (state) {
> > +                     ret = pinctrl_select_state(sdhst->pinctrl, state);
> > +                     if (ret) {
> > +                             dev_warn(mmc_dev(host->mmc),
> > +                                      "failed to select pinctrl state: %d\n", ret);
> > +                             return;
> > +                     }
> > +                     dev_dbg(mmc_dev(host->mmc), "switched to %s pinctrl state\n",
> > +                             ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180 ? "UHS" : "default");
> > +             }
> > +     }
> > +}
> > +
> >  static inline int spacemit_sdhci_get_clocks(struct device *dev,
> >                                           struct sdhci_pltfm_host *pltfm_host)
> >  {
> > @@ -242,6 +282,7 @@ static const struct sdhci_ops spacemit_sdhci_ops = {
> >       .set_bus_width          = sdhci_set_bus_width,
> >       .set_clock              = spacemit_sdhci_set_clock,
> >       .set_uhs_signaling      = spacemit_sdhci_set_uhs_signaling,
> > +     .voltage_switch         = spacemit_sdhci_voltage_switch,
> >  };
> >
> >  static const struct sdhci_pltfm_data spacemit_sdhci_k1_pdata = {
> > @@ -293,6 +334,24 @@ static int spacemit_sdhci_probe(struct platform_device *pdev)
> >
> >       host->mmc->caps |= MMC_CAP_NEED_RSP_BUSY;
> >
> > +     sdhst = sdhci_pltfm_priv(pltfm_host);
> ..
> > +     sdhst->pinctrl = devm_pinctrl_get(dev);
> > +     if (!IS_ERR(sdhst->pinctrl)) {
> > +             sdhst->pinctrl_default = pinctrl_lookup_state(sdhst->pinctrl, "default");
> > +             if (IS_ERR(sdhst->pinctrl_default))
> > +                     sdhst->pinctrl_default = NULL;
> > +
> > +             sdhst->pinctrl_uhs = pinctrl_lookup_state(sdhst->pinctrl, "state_uhs");
> > +             if (IS_ERR(sdhst->pinctrl_uhs))
> > +                     sdhst->pinctrl_uhs = NULL;
> > +
> > +             dev_dbg(dev, "pinctrl setup: default=%p, uhs=%p\n",
> > +                     sdhst->pinctrl_default, sdhst->pinctrl_uhs);
> > +     } else {
> > +             sdhst->pinctrl = NULL;
> > +             dev_dbg(dev, "pinctrl not available, voltage switching will work without it\n");
> > +     }
> > +
> how about creating a function spacemit_sdhci_get_pins()? similar as get
> resource for clock, will more readable.

Yes, I'll do that. Thank you for the feedback.

>
> >       ret = spacemit_sdhci_get_clocks(dev, pltfm_host);
> >       if (ret)
> >               goto err_pltfm;
> >
> > --
> > 2.53.0
> >
>
> --
> Yixun Lan (dlan)