D1 contains two pairs of LDOs. Since they have similar bindings, and
they always exist together, put them in a single driver.

The analog LDOs are relatively boring, with a single linear range. Their
one quirk is that a bandgap reference must be calibrated for them to
produce the correct voltage.

The system LDOs have the complication that their voltage step is not an
integer, so a custom .list_voltage is needed to get the rounding right.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---

Changes in v3:
 - Adjust control flow in sun20i_regulator_get_regmap() for clarity

Changes in v2:
 - Use decimal numbers for .n_voltages instead of field widths
 - Get the regmap from the parent device instead of a property/phandle

 drivers/regulator/Kconfig            |   8 +
 drivers/regulator/Makefile           |   1 +
 drivers/regulator/sun20i-regulator.c | 232 +++++++++++++++++++++++++++
 3 files changed, 241 insertions(+)
 create mode 100644 drivers/regulator/sun20i-regulator.c

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 23e3e4a35cc9..0c5727173fa0 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig

@@ -1262,6 +1262,14 @@ config REGULATOR_STW481X_VMMC
 	  This driver supports the internal VMMC regulator in the STw481x
 	  PMIC chips.
 
+config REGULATOR_SUN20I
+	tristate "Allwinner D1 internal LDOs"
+	depends on ARCH_SUNXI || COMPILE_TEST
+	depends on MFD_SYSCON && NVMEM
+	default ARCH_SUNXI
+	help
+	  This driver supports the internal LDOs in the Allwinner D1 SoC.
+
 config REGULATOR_SY7636A
 	tristate "Silergy SY7636A voltage regulator"
 	help

diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index fa49bb6cc544..5dff112eb015 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile

@@ -148,6 +148,7 @@ obj-$(CONFIG_REGULATOR_STM32_VREFBUF) += stm32-vrefbuf.o
 obj-$(CONFIG_REGULATOR_STM32_PWR) += stm32-pwr.o
 obj-$(CONFIG_REGULATOR_STPMIC1) += stpmic1_regulator.o
 obj-$(CONFIG_REGULATOR_STW481X_VMMC) += stw481x-vmmc.o
+obj-$(CONFIG_REGULATOR_SUN20I) += sun20i-regulator.o
 obj-$(CONFIG_REGULATOR_SY7636A) += sy7636a-regulator.o
 obj-$(CONFIG_REGULATOR_SY8106A) += sy8106a-regulator.o
 obj-$(CONFIG_REGULATOR_SY8824X) += sy8824x.o

diff --git a/drivers/regulator/sun20i-regulator.c b/drivers/regulator/sun20i-regulator.c
new file mode 100644
index 000000000000..46f3927d7d10
--- /dev/null
+++ b/drivers/regulator/sun20i-regulator.c

@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Copyright (c) 2021-2022 Samuel Holland <samuel@sholland.org>
+//