1 files changed, 260 insertions, 0 deletions
diff --git a/drivers/mmc/core/regulator.c b/drivers/mmc/core/regulator.c
new file mode 100644
index 000000000000..b6febbcf8978
--- /dev/null
+++ b/drivers/mmc/core/regulator.c
@@ -0,0 +1,260 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helper functions for MMC regulators.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/log2.h>
+#include <linux/regulator/consumer.h>
+
+#include <linux/mmc/host.h>
+
+#include "core.h"
+#include "host.h"
+
+#ifdef CONFIG_REGULATOR
+
+/**
+ * mmc_ocrbitnum_to_vdd - Convert a OCR bit number to its voltage
+ * @vdd_bit:	OCR bit number
+ * @min_uV:	minimum voltage value (mV)
+ * @max_uV:	maximum voltage value (mV)
+ *
+ * This function returns the voltage range according to the provided OCR
+ * bit number. If conversion is not possible a negative errno value returned.
+ */
+static int mmc_ocrbitnum_to_vdd(int vdd_bit, int *min_uV, int *max_uV)
+{
+	int		tmp;
+
+	if (!vdd_bit)
+		return -EINVAL;
+
+	/*
+	 * REVISIT mmc_vddrange_to_ocrmask() may have set some
+	 * bits this regulator doesn't quite support ... don't
+	 * be too picky, most cards and regulators are OK with
+	 * a 0.1V range goof (it's a small error percentage).
+	 */
+	tmp = vdd_bit - ilog2(MMC_VDD_165_195);
+	if (tmp == 0) {
+		*min_uV = 1650 * 1000;
+		*max_uV = 1950 * 1000;
+	} else {
+		*min_uV = 1900 * 1000 + tmp * 100 * 1000;
+		*max_uV = *min_uV + 100 * 1000;
+	}
+
+	return 0;
+}
+
+/**
+ * mmc_regulator_get_ocrmask - return mask of supported voltages
+ * @supply: regulator to use
+ *
+ * This returns either a negative errno, or a mask of voltages that
+ * can be provided to MMC/SD/SDIO devices using the specified voltage
+ * regulator.  This would normally be called before registering the
+ * MMC host adapter.
+ */
+static int mmc_regulator_get_ocrmask(struct regulator *supply)
+{
+	int			result = 0;
+	int			count;
+	int			i;
+	int			vdd_uV;
+	int			vdd_mV;
+
+	count = regulator_count_voltages(supply);
+	if (count < 0)
+		return count;
+
+	for (i = 0; i < count; i++) {
+		vdd_uV = regulator_list_voltage(supply, i);
+		if (vdd_uV <= 0)
+			continue;
+
+		vdd_mV = vdd_uV / 1000;
+		result |= mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
+	}
+
+	if (!result) {
+		vdd_uV = regulator_get_voltage(supply);
+		if (vdd_uV <= 0)
+			return vdd_uV;
+
+		vdd_mV = vdd_uV / 1000;
+		result = mmc_vddrange_to_ocrmask(vdd_mV, vdd_mV);
+	}
+
+	return result;
+}
+
+/**
+ * mmc_regulator_set_ocr - set regulator to match host->ios voltage
+ * @mmc: the host to regulate
+ * @supply: regulator to use
+ * @vdd_bit: zero for power off, else a bit number (host->ios.vdd)
+ *
+ * Returns zero on success, else negative errno.
+ *
+ * MMC host drivers may use this to enable or disable a regulator using
+ * a particular supply voltage.  This would normally be called from the
+ * set_ios() method.
+ */
+int mmc_regulator_set_ocr(struct mmc_host *mmc,
+			struct regulator *supply,
+			unsigned short vdd_bit)
+{
+	int			result = 0;
+	int			min_uV, max_uV;
+
+	if (vdd_bit) {
+		mmc_ocrbitnum_to_vdd(vdd_bit, &min_uV, &max_uV);
+
+		result = regulator_set_voltage(supply, min_uV, max_uV);
+		if (result == 0 && !mmc->regulator_enabled) {
+			result = regulator_enable(supply);
+			if (!result)
+				mmc->regulator_enabled = true;
+		}
+	} else if (mmc->regulator_enabled) {
+		result = regulator_disable(supply);
+		if (result == 0)
+			mmc->regulator_enabled = false;
+	}
+
+	if (result)
+		dev_err(mmc_dev(mmc),
+			"could not set regulator OCR (%d)\n", result);
+	return result;
+}
+EXPORT_SYMBOL_GPL(mmc_regulator_set_ocr);
+
+static int mmc_regulator_set_voltage_if_supported(struct regulator *regulator,
+						  int min_uV, int target_uV,
+						  int max_uV)
+{
+	/*
+	 * Check if supported first to avoid errors since we may try several
+	 * signal levels during power up and don't want to show errors.
+	 */
+	if (!regulator_is_supported_voltage(regulator, min_uV, max_uV))
+		return -EINVAL;
+
+	return regulator_set_voltage_triplet(regulator, min_uV, target_uV,
+					     max_uV);
+}
+
+/**
+ * mmc_regulator_set_vqmmc - Set VQMMC as per the ios
+ *
+ * For 3.3V signaling, we try to match VQMMC to VMMC as closely as possible.
+ * That will match the behavior of old boards where VQMMC and VMMC were supplied
+ * by the same supply.  The Bus Operating conditions for 3.3V signaling in the
+ * SD card spec also define VQMMC in terms of VMMC.
+ * If this is not possible we'll try the full 2.7-3.6V of the spec.
+ *
+ * For 1.2V and 1.8V signaling we'll try to get as close as possible to the
+ * requested voltage.  This is definitely a good idea for UHS where there's a
+ * separate regulator on the card that's trying to make 1.8V and it's best if
+ * we match.
+ *
+ * This function is expected to be used by a controller's
+ * start_signal_voltage_switch() function.
+ */
+int mmc_regulator_set_vqmmc(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	struct device *dev = mmc_dev(mmc);
+	int ret, volt, min_uV, max_uV;
+
+	/* If no vqmmc supply then we can't change the voltage */
+	if (IS_ERR(mmc->supply.vqmmc))
+		return -EINVAL;
+
+	switch (ios->signal_voltage) {
+	case MMC_SIGNAL_VOLTAGE_120:
+		return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
+						1100000, 1200000, 1300000);
+	case MMC_SIGNAL_VOLTAGE_180:
+		return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
+						1700000, 1800000, 1950000);
+	case MMC_SIGNAL_VOLTAGE_330:
+		ret = mmc_ocrbitnum_to_vdd(mmc->ios.vdd, &volt, &max_uV);
+		if (ret < 0)
+			return ret;
+
+		dev_dbg(dev, "%s: found vmmc voltage range of %d-%duV\n",
+			__func__, volt, max_uV);
+
+		min_uV = max(volt - 300000, 2700000);
+		max_uV = min(max_uV + 200000, 3600000);
+
+		/*
+		 * Due to a limitation in the current implementation of
+		 * regulator_set_voltage_triplet() which is taking the lowest
+		 * voltage possible if below the target, search for a suitable
+		 * voltage in two steps and try to stay close to vmmc
+		 * with a 0.3V tolerance at first.
+		 */
+		if (!mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
+						min_uV, volt, max_uV))
+			return 0;
+
+		return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
+						2700000, volt, 3600000);
+	default:
+		return -EINVAL;
+	}
+}
+EXPORT_SYMBOL_GPL(mmc_regulator_set_vqmmc);
+
+#else
+
+static inline int mmc_regulator_get_ocrmask(struct regulator *supply)
+{
+	return 0;
+}
+
+#endif /* CONFIG_REGULATOR */
+
+/**
+ * mmc_regulator_get_supply - try to get VMMC and VQMMC regulators for a host
+ * @mmc: the host to regulate
+ *
+ * Returns 0 or errno. errno should be handled, it is either a critical error
+ * or -EPROBE_DEFER. 0 means no critical error but it does not mean all
+ * regulators have been found because they all are optional. If you require
+ * certain regulators, you need to check separately in your driver if they got
+ * populated after calling this function.
+ */
+int mmc_regulator_get_supply(struct mmc_host *mmc)
+{
+	struct device *dev = mmc_dev(mmc);
+	int ret;
+
+	mmc->supply.vmmc = devm_regulator_get_optional(dev, "vmmc");
+	mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");
+
+	if (IS_ERR(mmc->supply.vmmc)) {
+		if (PTR_ERR(mmc->supply.vmmc) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+		dev_dbg(dev, "No vmmc regulator found\n");
+	} else {
+		ret = mmc_regulator_get_ocrmask(mmc->supply.vmmc);
+		if (ret > 0)
+			mmc->ocr_avail = ret;
+		else
+			dev_warn(dev, "Failed getting OCR mask: %d\n", ret);
+	}
+
+	if (IS_ERR(mmc->supply.vqmmc)) {
+		if (PTR_ERR(mmc->supply.vqmmc) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+		dev_dbg(dev, "No vqmmc regulator found\n");
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mmc_regulator_get_supply);