[PATCH V20 04/22] mmc: core: Extend support for mmc regulators with a vqmmc2

Victor Shih
2024-09-05T10:20:23Z

From: Ulf Hansson <ulf.hansson@linaro.org>

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>
---

Updates in V10:
- Modify the commit message.

Updates in V4:
- Moved the voltage defines into this patch.

---

drivers/mmc/core/regulator.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/mmc/host.h | 11 +++++++++++
2 files changed, 45 insertions(+)

diff --git a/drivers/mmc/core/regulator.c b/drivers/mmc/core/regulator.c
index 005247a49e51..208c27cfa505 100644
--- 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)
@@ -271,6 +299,12 @@ 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 f1cf09ea1f72..841f0ba850aa 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -74,6 +74,9 @@ 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
@@ -307,6 +310,7 @@ 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 {
@@ -589,6 +593,7 @@ 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,
@@ -602,6 +607,12 @@ 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);
--
2.25.1