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, 87 insertions, 0 deletions

diff --git a/include/linux/regulator/gpio-regulator.h b/include/linux/regulator/gpio-regulator.h
new file mode 100644
index 000000000000..19fbd267406d
--- /dev/null
+++ b/include/linux/regulator/gpio-regulator.h
@@ -0,0 +1,87 @@
+/*
+ * gpio-regulator.h
+ *
+ * Copyright 2011 Heiko Stuebner <heiko@sntech.de>
+ *
+ * based on fixed.h
+ *
+ * Copyright 2008 Wolfson Microelectronics PLC.
+ *
+ * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ * Copyright (c) 2009 Nokia Corporation
+ * Roger Quadros <ext-roger.quadros@nokia.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ */
+
+#ifndef __REGULATOR_GPIO_H
+#define __REGULATOR_GPIO_H
+
+struct regulator_init_data;
+
+enum regulator_type;
+
+/**
+ * struct gpio_regulator_state - state description
+ * @value:              microvolts or microamps
+ * @gpios:              bitfield of gpio target-states for the value
+ *
+ * This structure describes a supported setting of the regulator
+ * and the necessary gpio-state to achieve it.
+ *
+ * The n-th bit in the bitfield describes the state of the n-th GPIO
+ * from the gpios-array defined in gpio_regulator_config below.
+ */
+struct gpio_regulator_state {
+        int value;
+        int gpios;
+};
+
+/**
+ * struct gpio_regulator_config - config structure
+ * @supply_name:        Name of the regulator supply
+ * @enable_gpio:        GPIO to use for enable control
+ *                      set to -EINVAL if not used
+ * @enable_high:        Polarity of enable GPIO
+ *                      1 = Active high, 0 = Active low
+ * @enabled_at_boot:    Whether regulator has been enabled at
+ *                      boot or not. 1 = Yes, 0 = No
+ *                      This is used to keep the regulator at
+ *                      the default state
+ * @startup_delay:      Start-up time in microseconds
+ * @gpios:              Array containing the gpios needed to control
+ *                      the setting of the regulator
+ * @nr_gpios:           Number of gpios
+ * @states:             Array of gpio_regulator_state entries describing
+ *                      the gpio state for specific voltages
+ * @nr_states:          Number of states available
+ * @regulator_type:     either REGULATOR_CURRENT or REGULATOR_VOLTAGE
+ * @init_data:          regulator_init_data
+ *
+ * This structure contains gpio-voltage regulator configuration
+ * information that must be passed by platform code to the
+ * gpio-voltage regulator driver.
+ */
+struct gpio_regulator_config {
+        const char *supply_name;
+
+        int enable_gpio;
+        unsigned enable_high:1;
+        unsigned enabled_at_boot:1;
+        unsigned startup_delay;
+
+        struct gpio *gpios;
+        int nr_gpios;
+
+        struct gpio_regulator_state *states;
+        int nr_states;
+
+        enum regulator_type type;
+        struct regulator_init_data *init_data;
+};
+
+#endif