regulator: Add driver for gpio-controlled regulators

This patch adds support for regulators that can be controlled via gpios.

Examples for such regulators are the TI-tps65024x voltage regulators
with 4 fixed and 1 runtime-switchable voltage regulators
or the TI-bq240XX charger regulators.

The number of controlling gpios is not limited, the mapping between
voltage/current and target gpio state is done via the states map
and the driver can be used for either voltage or current regulators.

A mapping for a regulator with two GPIOs could look like:

gpios = {
	{ .gpio = GPIO1, .flags = GPIOF_OUT_INIT_HIGH, .label = "gpio name 1" },
	{ .gpio = GPIO2, .flags = GPIOF_OUT_INIT_LOW,  .label = "gpio name 2" },
}

The flags element of the gpios array determines the initial state of
the gpio, set during probe. The initial state of the regulator is also
calculated from these values

states = {
	{ .value = volt_or_cur1, .gpios = (0 << 1) | (0 << 0) },
	{ .value = volt_or_cur2, .gpios = (0 << 1) | (1 << 0) },
	{ .value = volt_or_cur3, .gpios = (1 << 1) | (0 << 0) },
	{ .value = volt_or_cur4, .gpios = (1 << 1) | (1 << 0) },
}

The target-state for the n-th gpio is determined by the n-th bit
in the bitfield of the target-value.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index c7fd2c0e3f2b..5e0c7b664732 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -64,6 +64,15 @@ config REGULATOR_USERSPACE_CONSUMER
 
           If unsure, say no.
 
+config REGULATOR_GPIO
+        tristate "GPIO regulator support"
+        help
+          This driver provides support for regulators that can be
+          controlled via gpios.
+          It is capable of supporting current and voltage regulators
+          and the platform has to provide a mapping of GPIO-states
+          to target volts/amps.
+
 config REGULATOR_BQ24022
         tristate "TI bq24022 Dual Input 1-Cell Li-Ion Charger IC"
         help