mmc: core: Extend support for mmc regulators with a vqmmc2

To allow an additional external regulator to be controlled by an mmc host
driver, let's add support for a vqmmc2 regulator to the mmc core.

For an SD UHS-II interface the vqmmc2 regulator may correspond to the so
called vdd2 supply, as described by the SD spec. Initially, only 1.8V is
needed, hence limit the new helper function, mmc_regulator_set_vqmmc2() to
this too.

Note that, to allow for flexibility mmc host drivers need to manage the
enable/disable of the vqmmc2 regulator themselves, while the regulator is
looked up through the common mmc_regulator_get_supply().

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20240913102836.6144-5-victorshihgli@gmail.com

diff --git a/drivers/mmc/core/regulator.c b/drivers/mmc/core/regulator.c
index 01747ab1024ec1a33615dc63d40cb66777e81949..3dae2e9b7978134db3bd2affb425677d1d7b34e7 100644 (file)
--- a/drivers/mmc/core/regulator.c
+++ b/drivers/mmc/core/regulator.c
@@ -226,6 +226,33 @@ int mmc_regulator_set_vqmmc(struct mmc_host *mmc, struct mmc_ios *ios)
 }
 EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc);
 
+/**
+ * mmc_regulator_set_vqmmc2 - Set vqmmc2 as per the ios->vqmmc2_voltage
+ * @mmc: The mmc host to regulate
+ * @ios: The io bus settings
+ *
+ * Sets a new voltage level for the vqmmc2 regulator, which may correspond to
+ * the vdd2 regulator for an SD UHS-II interface. This function is expected to
+ * be called by mmc host drivers.
+ *
+ * Returns a negative error code on failure, zero if the voltage level was
+ * changed successfully or a positive value if the level didn't need to change.
+ */
+int mmc_regulator_set_vqmmc2(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+       if (IS_ERR(mmc->supply.vqmmc2))
+               return -EINVAL;
+
+       switch (ios->vqmmc2_voltage) {
+       case MMC_VQMMC2_VOLTAGE_180:
+               return mmc_regulator_set_voltage_if_supported(
+                       mmc->supply.vqmmc2, 1700000, 1800000, 1950000);
+       default:
+               return -EINVAL;
+       }
+}
+EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc2);
+
 #else
 
 static inline int mmc_regulator_get_ocrmask(struct regulator *supply)
@@ -252,6 +279,7 @@ int mmc_regulator_get_supply(struct mmc_host *mmc)
 
        mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc");
        mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");
+       mmc->supply.vqmmc2 = devm_regulator_get_optional(dev, "vqmmc2");
 
        if (IS_ERR(mmc->supply.vmmc)) {
                if (PTR_ERR(mmc->supply.vmmc) == -EPROBE_DEFER)
@@ -275,6 +303,12 @@ int mmc_regulator_get_supply(struct mmc_host *mmc)
                dev_dbg(dev, "No vqmmc regulator found\n");
        }
 
+       if (IS_ERR(mmc->supply.vqmmc2)) {
+               if (PTR_ERR(mmc->supply.vqmmc2) == -EPROBE_DEFER)
+                       return -EPROBE_DEFER;
+               dev_dbg(dev, "No vqmmc2 regulator found\n");
+       }
+
        return 0;
 }
 EXPORT_SYMBOL_GPL(mmc_regulator_get_supply);

diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 9a148280bf42d51ff66f3e5b6e3318534685b6c7..a7f790c75bc8545c72a144276b47274fda3dd161 100644 (file)
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -75,6 +75,9 @@ struct mmc_ios {
 #define MMC_SIGNAL_VOLTAGE_180 1
 #define MMC_SIGNAL_VOLTAGE_120 2
 
+       unsigned char   vqmmc2_voltage;
+#define MMC_VQMMC2_VOLTAGE_180 0
+
        unsigned char   drv_type;               /* driver type (A, B, C, D) */
 
 #define MMC_SET_DRIVER_TYPE_B  0
@@ -308,6 +311,7 @@ struct mmc_pwrseq;
 struct mmc_supply {
        struct regulator *vmmc;         /* Card power supply */
        struct regulator *vqmmc;        /* Optional Vccq supply */
+       struct regulator *vqmmc2;       /* Optional supply for phy */
 };
 
 struct mmc_ctx {
@@ -590,6 +594,7 @@ int mmc_regulator_set_ocr(struct mmc_host *mmc,
                        struct regulator *supply,
                        unsigned short vdd_bit);
 int mmc_regulator_set_vqmmc(struct mmc_host *mmc, struct mmc_ios *ios);
+int mmc_regulator_set_vqmmc2(struct mmc_host *mmc, struct mmc_ios *ios);
 #else
 static inline int mmc_regulator_set_ocr(struct mmc_host *mmc,
                                 struct regulator *supply,
@@ -603,6 +608,12 @@ static inline int mmc_regulator_set_vqmmc(struct mmc_host *mmc,
 {
        return -EINVAL;
 }
+
+static inline int mmc_regulator_set_vqmmc2(struct mmc_host *mmc,
+                                          struct mmc_ios *ios)
+{
+       return -EINVAL;
+}
 #endif
 
 int mmc_regulator_get_supply(struct mmc_host *mmc);