The TPS68470 PMIC provides Clocks, GPIOs and Regulators. At present in
the kernel the Regulators and Clocks are controlled by an OpRegion
driver designed to work with power control methods defined in ACPI, but
some platforms lack those methods, meaning drivers need to be able to
consume the resources of these chips through the usual frameworks.

This commit adds a driver for the regulators provided by the tps68470,
and is designed to bind to the platform_device registered by the
intel_skl_int3472 module.

This is based on this out of tree driver written by Intel:
https://github.com/intel/linux-intel-lts/blob/4.14/base/drivers/regulator/tps68470-regulator.c
with various cleanups added.

Signed-off-by: Hans de Goede <redacted>
---
Changes in v2:
- Update the comment on why a subsys_initcall is used to register the drv
- Make struct regulator_ops const
---
  drivers/regulator/Kconfig              |   9 ++
  drivers/regulator/Makefile             |   1 +
  drivers/regulator/tps68470-regulator.c | 193 +++++++++++++++++++++++++
  3 files changed, 203 insertions(+)
  create mode 100644 drivers/regulator/tps68470-regulator.c

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 4fd13b06231f..d107af5bff6c 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig

@@ -1339,6 +1339,15 @@ config REGULATOR_TPS65912
  	help
  	    This driver supports TPS65912 voltage regulator chip.
  
+config REGULATOR_TPS68470
+	tristate "TI TPS68370 PMIC Regulators Driver"
+	depends on INTEL_SKL_INT3472
+	help
+	  This driver adds support for the TPS68470 PMIC to register
+	  regulators against the usual framework.
+
+	  The module will be called "tps68470-regulator"