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.
Tested-by: Anand Moon <linux.amoon@gmail.com>
Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
---
drivers/mmc/host/sdhci-of-k1.c | 72 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)
diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
index 0dd06fc19b8574ae1b00f7e5d09b7d4c87d06770..234e258af25996e7bbcd0b70366c7480bf62bee7 100644
--- a/drivers/mmc/host/sdhci-of-k1.c
+++ b/drivers/mmc/host/sdhci-of-k1.c
@@ -16,6 +16,7 @@
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/reset.h>
+#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include "sdhci.h"
@@ -71,6 +72,9 @@
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 */
@@ -219,6 +223,46 @@ static void spacemit_sdhci_pre_hs400_to_hs200(struct mmc_host *mmc)
SPACEMIT_SDHC_PHY_CTRL_REG);
}
+static int spacemit_sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
+ struct mmc_ios *ios)
+{
+ struct sdhci_host *host = mmc_priv(mmc);
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct spacemit_sdhci_host *sdhst = sdhci_pltfm_priv(pltfm_host);
+ struct pinctrl_state *state;
+ int ret;
+
+ ret = sdhci_start_signal_voltage_switch(mmc, ios);
+ if (ret)
+ return ret;
+
+ if (!sdhst->pinctrl)
+ return 0;
+
+ /* Select appropriate pinctrl state based on signal voltage */
+ 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(mmc), "unsupported voltage %d\n", ios->signal_voltage);
+ return 0;
+ }
+
+ ret = pinctrl_select_state(sdhst->pinctrl, state);
+ if (ret) {
+ dev_warn(mmc_dev(mmc), "failed to select pinctrl state: %d\n", ret);
+ return 0;
+ }
+ dev_dbg(mmc_dev(mmc), "switched to %s pinctrl state\n",
+ ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180 ? "UHS" : "default");
+
+ return 0;
+}
+
static inline int spacemit_sdhci_get_clocks(struct device *dev,
struct sdhci_pltfm_host *pltfm_host)
{
@@ -252,6 +296,30 @@ static inline int spacemit_sdhci_get_resets(struct device *dev)
return 0;
}
+static inline void spacemit_sdhci_get_pins(struct device *dev,
+ struct sdhci_pltfm_host *pltfm_host)
+{
+ struct spacemit_sdhci_host *sdhst = sdhci_pltfm_priv(pltfm_host);
+
+ sdhst->pinctrl = devm_pinctrl_get(dev);
+ if (IS_ERR(sdhst->pinctrl)) {
+ sdhst->pinctrl = NULL;
+ dev_dbg(dev, "pinctrl not available, voltage switching will work without it\n");
+ return;
+ }
+
+ 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);
+}
+
static const struct sdhci_ops spacemit_sdhci_ops = {
.get_max_clock = spacemit_sdhci_clk_get_max_clock,
.reset = spacemit_sdhci_reset,
@@ -324,6 +392,10 @@ static int spacemit_sdhci_probe(struct platform_device *pdev)
host->mmc->caps |= MMC_CAP_NEED_RSP_BUSY;
+ spacemit_sdhci_get_pins(dev, pltfm_host);
+
+ host->mmc_host_ops.start_signal_voltage_switch = spacemit_sdhci_start_signal_voltage_switch;
+
ret = spacemit_sdhci_get_clocks(dev, pltfm_host);
if (ret)
goto err_pltfm;
--
2.53.0On Mon, 23 Mar 2026 at 11:19, Iker Pedrosa <ikerpedrosam@gmail.com> 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. Adding pinctrl support like this should require an update to the DT binding. Please fold in a patch that precedes the $subject patch and ensure the DT maintainers are cced on it. > > Tested-by: Anand Moon <linux.amoon@gmail.com> > Tested-by: Trevor Gamblin <tgamblin@baylibre.com> > Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com> > --- > drivers/mmc/host/sdhci-of-k1.c | 72 ++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 72 insertions(+) > Kind regards Uffe
On 23/03/2026 12:19, 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.
>
> Tested-by: Anand Moon <linux.amoon@gmail.com>
> Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
> Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
> drivers/mmc/host/sdhci-of-k1.c | 72 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 72 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-of-k1.c b/drivers/mmc/host/sdhci-of-k1.c
> index 0dd06fc19b8574ae1b00f7e5d09b7d4c87d06770..234e258af25996e7bbcd0b70366c7480bf62bee7 100644
> --- a/drivers/mmc/host/sdhci-of-k1.c
> +++ b/drivers/mmc/host/sdhci-of-k1.c
> @@ -16,6 +16,7 @@
> #include <linux/of.h>
> #include <linux/of_device.h>
> #include <linux/reset.h>
> +#include <linux/pinctrl/consumer.h>
> #include <linux/platform_device.h>
>
> #include "sdhci.h"
> @@ -71,6 +72,9 @@
> 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 */
> @@ -219,6 +223,46 @@ static void spacemit_sdhci_pre_hs400_to_hs200(struct mmc_host *mmc)
> SPACEMIT_SDHC_PHY_CTRL_REG);
> }
>
> +static int spacemit_sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
> + struct mmc_ios *ios)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct spacemit_sdhci_host *sdhst = sdhci_pltfm_priv(pltfm_host);
> + struct pinctrl_state *state;
> + int ret;
> +
> + ret = sdhci_start_signal_voltage_switch(mmc, ios);
> + if (ret)
> + return ret;
> +
> + if (!sdhst->pinctrl)
> + return 0;
> +
> + /* Select appropriate pinctrl state based on signal voltage */
> + 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(mmc), "unsupported voltage %d\n", ios->signal_voltage);
> + return 0;
> + }
> +
> + ret = pinctrl_select_state(sdhst->pinctrl, state);
> + if (ret) {
> + dev_warn(mmc_dev(mmc), "failed to select pinctrl state: %d\n", ret);
> + return 0;
> + }
> + dev_dbg(mmc_dev(mmc), "switched to %s pinctrl state\n",
> + ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180 ? "UHS" : "default");
> +
> + return 0;
> +}
> +
> static inline int spacemit_sdhci_get_clocks(struct device *dev,
> struct sdhci_pltfm_host *pltfm_host)
> {
> @@ -252,6 +296,30 @@ static inline int spacemit_sdhci_get_resets(struct device *dev)
> return 0;
> }
>
> +static inline void spacemit_sdhci_get_pins(struct device *dev,
> + struct sdhci_pltfm_host *pltfm_host)
> +{
> + struct spacemit_sdhci_host *sdhst = sdhci_pltfm_priv(pltfm_host);
> +
> + sdhst->pinctrl = devm_pinctrl_get(dev);
> + if (IS_ERR(sdhst->pinctrl)) {
> + sdhst->pinctrl = NULL;
> + dev_dbg(dev, "pinctrl not available, voltage switching will work without it\n");
> + return;
> + }
> +
> + 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);
> +}
> +
> static const struct sdhci_ops spacemit_sdhci_ops = {
> .get_max_clock = spacemit_sdhci_clk_get_max_clock,
> .reset = spacemit_sdhci_reset,
> @@ -324,6 +392,10 @@ static int spacemit_sdhci_probe(struct platform_device *pdev)
>
> host->mmc->caps |= MMC_CAP_NEED_RSP_BUSY;
>
> + spacemit_sdhci_get_pins(dev, pltfm_host);
> +
> + host->mmc_host_ops.start_signal_voltage_switch = spacemit_sdhci_start_signal_voltage_switch;
> +
> ret = spacemit_sdhci_get_clocks(dev, pltfm_host);
> if (ret)
> goto err_pltfm;
>
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