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Subject[RFC v2] Add gpio-regulator driver
Date
As suggested by Mark Brown, I created a more generalised gpio-regulator driver.

It is definitly not finished - it just implements my idea and compiles - real world
testing and fixing follows this weekend. If possible I'd just like to make sure I'm
on the right track this time :-) .

As the mechanisms of setting gpio states don't change with the regulator type
it is also possible to use it as a current regulator.
Therefore it could replace i.e. the bq24022/bq2407x driver later on.

Platform data for the 3 gpio controlled regulators I know of could look like:
struct gpio_regulator_config bq24022 = {
.supply_name = "bq24022",
.gpios = {
GPIO_ISET2,
},
.nr_gpios = 1,
.gpio_states = {
{ .value = 100000, gpios = (0 << 0) },
{ .value = 500000, gpios = (1 << 0) },
},
.nr_gpio_states = 2,
.state_at_boot = (0 << 0),
.type = REGULATOR_CURRENT,
};
struct gpio_regulator_config bq24075 = {
.supply_name = "bq24075",
.gpios = {
GPIO_EN1,
GPIO_EN2,
},
.nr_gpios = 2,
.gpio_states = {
{ .value = 100000, gpios = (0 << 1) | (0 << 0) },
{ .value = 500000, gpios = (0 << 1) | (1 << 0) },
{ .value = 975000, gpios = (1 << 1) | (0 << 0) },
},
.nr_gpio_states = 3,
.state_at_boot = (0 << 1)|(0 << 0),
.type = REGULATOR_CURRENT,
};
struct gpio_regulator_config tps650240 = {
.supply_name = "tps650240-dcdc3",
.gpios = {
GPIO_DEFDCDC3,
},
.nr_gpios = 1,
.gpio_states = {
{ .value = 1000000, gpios = (0 << 0) },
{ .value = 1300000, gpios = (1 << 0) },
},
.nr_gpio_states = 2,
.state_at_boot = (1 << 0),
.type = REGULATOR_VOLTAGE,
};
Comments?

---
drivers/regulator/Kconfig | 6 +
drivers/regulator/Makefile | 1 +
drivers/regulator/gpio-regulator.c | 361 ++++++++++++++++++++++++++++++
include/linux/regulator/gpio-regulator.h | 84 +++++++
4 files changed, 452 insertions(+), 0 deletions(-)
create mode 100644 drivers/regulator/gpio-regulator.c
create mode 100644 include/linux/regulator/gpio-regulator.h
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 8510d8c..57e2ccc 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -72,6 +72,12 @@ 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 by setting gpios.
+
config REGULATOR_BQ24022
tristate "TI bq24022 Dual Input 1-Cell Li-Ion Charger IC"
help
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 5a8f4ee..44dcac3 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_REGULATOR_SWITCHED_VOLTAGE) += switch.o
obj-$(CONFIG_REGULATOR_VIRTUAL_CONSUMER) += virtual.o
obj-$(CONFIG_REGULATOR_USERSPACE_CONSUMER) += userspace-consumer.o

+obj-$(CONFIG_REGULATOR_GPIO) += gpio-regulator.o
obj-$(CONFIG_REGULATOR_AD5398) += ad5398.o
obj-$(CONFIG_REGULATOR_BQ24022) += bq24022.o
obj-$(CONFIG_REGULATOR_LP3971) += lp3971.o
diff --git a/drivers/regulator/gpio-regulator.c b/drivers/regulator/gpio-regulator.c
new file mode 100644
index 0000000..ed7ed40
--- /dev/null
+++ b/drivers/regulator/gpio-regulator.c
@@ -0,0 +1,363 @@
+/*
+ * gpio-regulator.c
+ *
+ * Copyright 2011 Heiko Stuebner <heiko@sntech.de>
+ *
+ * based on fixed.c
+ *
+ * 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.
+ *
+ * This is useful for systems with mixed controllable and
+ * non-controllable regulators, as well as for allowing testing on
+ * systems with no controllable regulators.
+ */
+
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/gpio-regulator.h>
+#include <linux/gpio.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+
+struct gpio_regulator_data {
+ struct regulator_desc desc;
+ struct regulator_dev *dev;
+
+ int enable_gpio;
+ bool enable_high;
+ bool is_enabled;
+ unsigned startup_delay;
+
+ int *gpios;
+ int nr_gpios;
+
+ struct gpio_regulator_state *gpio_states;
+ int nr_gpio_states;
+
+ int state;
+};
+
+static int gpio_regulator_is_enabled(struct regulator_dev *dev)
+{
+ struct gpio_regulator_data *data = rdev_get_drvdata(dev);
+
+ return data->is_enabled;
+}
+
+static int gpio_regulator_enable(struct regulator_dev *dev)
+{
+ struct gpio_regulator_data *data = rdev_get_drvdata(dev);
+
+ if (gpio_is_valid(data->enable_gpio)) {
+ gpio_set_value_cansleep(data->enable_gpio, data->enable_high);
+ data->is_enabled = true;
+ }
+
+ return 0;
+}
+
+static int gpio_regulator_disable(struct regulator_dev *dev)
+{
+ struct gpio_regulator_data *data = rdev_get_drvdata(dev);
+
+ if (gpio_is_valid(data->enable_gpio)) {
+ gpio_set_value_cansleep(data->enable_gpio, !data->enable_high);
+ data->is_enabled = false;
+ }
+
+ return 0;
+}
+
+static int gpio_regulator_enable_time(struct regulator_dev *dev)
+{
+ struct gpio_regulator_data *data = rdev_get_drvdata(dev);
+
+ return data->startup_delay;
+}
+
+static int gpio_regulator_get_value(struct regulator_dev *dev)
+{
+ struct gpio_regulator_data *data = rdev_get_drvdata(dev);
+ int ptr;
+
+ for (ptr = 0; ptr < data->nr_gpio_states; ptr++)
+ if (data->gpio_states[ptr].gpios == data->state)
+ return data->gpio_states[ptr].value;
+
+ return -EINVAL;
+}
+
+static int gpio_regulator_set_value(struct regulator_dev *dev,
+ int min, int max)
+{
+ struct gpio_regulator_data *data = rdev_get_drvdata(dev);
+ int ptr, target, state;
+
+ target = -1;
+ for (ptr = 0; ptr < data->nr_gpio_states; ptr++)
+ if (data->gpio_states[ptr].value >= min &&
+ data->gpio_states[ptr].value <= max)
+ target = data->gpio_states[ptr].gpios;
+
+ if (target < 0)
+ return -EINVAL;
+
+ for (ptr = 0; ptr < data->nr_gpios; ptr++) {
+ state = (target & (1 << ptr)) >> ptr;
+ gpio_set_value(data->gpios[ptr], state);
+ }
+
+ data->state = target;
+
+ return 0;
+}
+
+static int gpio_regulator_set_voltage(struct regulator_dev *dev,
+ int min_uV, int max_uV,
+ unsigned *selector)
+{
+ return gpio_regulator_set_value(dev, min_uV, max_uV);
+}
+
+static int gpio_regulator_list_voltage(struct regulator_dev *dev,
+ unsigned selector)
+{
+ struct gpio_regulator_data *data = rdev_get_drvdata(dev);
+
+ if (selector >= data->nr_gpio_states)
+ return -EINVAL;
+
+ return data->gpio_states[selector].value;
+}
+
+static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
+ int min_uA, int max_uA)
+{
+ return gpio_regulator_set_value(dev, min_uA, max_uA);
+}
+
+static struct regulator_ops gpio_regulator_voltage_ops = {
+ .is_enabled = gpio_regulator_is_enabled,
+ .enable = gpio_regulator_enable,
+ .disable = gpio_regulator_disable,
+ .enable_time = gpio_regulator_enable_time,
+ .get_voltage = gpio_regulator_get_value,
+ .set_voltage = gpio_regulator_set_voltage,
+ .list_voltage = gpio_regulator_list_voltage,
+};
+
+static struct regulator_ops gpio_regulator_current_ops = {
+ .is_enabled = gpio_regulator_is_enabled,
+ .enable = gpio_regulator_enable,
+ .disable = gpio_regulator_disable,
+ .enable_time = gpio_regulator_enable_time,
+ .get_current_limit = gpio_regulator_get_value,
+ .set_current_limit = gpio_regulator_set_current_limit,
+};
+
+static int __devinit gpio_regulator_probe(struct platform_device *pdev)
+{
+ struct gpio_regulator_config *config = pdev->dev.platform_data;
+ struct gpio_regulator_data *drvdata;
+ int ptr, ret, state;
+
+ drvdata = kzalloc(sizeof(struct gpio_regulator_data), GFP_KERNEL);
+ if (drvdata == NULL) {
+ dev_err(&pdev->dev, "Failed to allocate device data\n");
+ return -ENOMEM;
+ }
+
+ drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
+ if (drvdata->desc.name == NULL) {
+ dev_err(&pdev->dev, "Failed to allocate supply name\n");
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ drvdata->gpios = kmalloc(config->nr_gpios * sizeof(int), GFP_KERNEL);
+ if (drvdata->gpios == NULL) {
+ dev_err(&pdev->dev, "Failed to allocate gpio data\n");
+ ret = -ENOMEM;
+ goto err_name;
+ }
+ /* init gpios negative; ability to deinitialize only the set ones */
+ for (ptr = 0; ptr < config->nr_gpios; ptr++)
+ drvdata->gpios[ptr] = -EINVAL;
+
+ drvdata->gpio_states = kmemdup(config->gpio_states,
+ config->nr_gpio_states *
+ sizeof(struct gpio_regulator_state),
+ GFP_KERNEL);
+ if (drvdata == NULL) {
+ dev_err(&pdev->dev, "Failed to allocate state data\n");
+ ret = -ENOMEM;
+ goto err_memgpio;
+ }
+
+ drvdata->desc.type = REGULATOR_VOLTAGE;
+ drvdata->desc.owner = THIS_MODULE;
+
+ /* if we are a voltage regulator */
+ switch (config->type) {
+ case REGULATOR_VOLTAGE:
+ drvdata->desc.ops = &gpio_regulator_voltage_ops;
+ drvdata->desc.n_voltages = config->nr_gpio_states;
+ break;
+ case REGULATOR_CURRENT:
+ drvdata->desc.ops = &gpio_regulator_current_ops;
+ break;
+ default:
+ dev_err(&pdev->dev, "No regulator type set\n");
+ ret = -EINVAL;
+ goto err_memgpio;
+ break;
+ }
+
+ drvdata->enable_gpio = config->enable_gpio;
+ drvdata->startup_delay = config->startup_delay;
+
+ if (gpio_is_valid(config->enable_gpio)) {
+ drvdata->enable_high = config->enable_high;
+
+ ret = gpio_request(config->enable_gpio, config->supply_name);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "Could not obtain regulator enable GPIO %d: %d\n",
+ config->enable_gpio, ret);
+ goto err_memstate;
+ }
+
+ /* set output direction without changing state
+ * to prevent glitch
+ */
+ drvdata->is_enabled = config->enabled_at_boot;
+ ret = drvdata->is_enabled ?
+ config->enable_high : !config->enable_high;
+
+ ret = gpio_direction_output(config->enable_gpio, ret);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "Could not configure regulator enable GPIO %d direction: %d\n",
+ config->enable_gpio, ret);
+ goto err_enablegpio;
+ }
+ } else {
+ /* Regulator without GPIO control is considered
+ * always enabled
+ */
+ drvdata->is_enabled = true;
+ }
+
+ drvdata->nr_gpios = config->nr_gpios;
+ for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
+ ret = gpio_request(config->gpios[ptr], config->supply_name);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "Could not obtain regulator setting GPIO %d: %d\n",
+ config->gpios[ptr], ret);
+ goto err_stategpio;
+ }
+
+ drvdata->gpios[ptr] = config->gpios[ptr];
+
+ state = (config->state_at_boot & (1 << ptr)) >> ptr;
+ ret = gpio_direction_output(drvdata->gpios[ptr], state);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "Could not configure regulator enable GPIO %d direction: %d\n",
+ drvdata->gpios[ptr], ret);
+ goto err_stategpio;
+ }
+ }
+ drvdata->state = config->state_at_boot;
+
+ drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
+ config->init_data, drvdata);
+ if (IS_ERR(drvdata->dev)) {
+ ret = PTR_ERR(drvdata->dev);
+ dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
+ goto err_stategpio;
+ }
+
+ platform_set_drvdata(pdev, drvdata);
+
+ return 0;
+
+err_stategpio:
+ for (ptr = 0; ptr < config->nr_gpios; ptr++)
+ if (gpio_is_valid(drvdata->gpios[ptr]))
+ gpio_free(drvdata->gpios[ptr]);
+err_enablegpio:
+ if (gpio_is_valid(config->enable_gpio))
+ gpio_free(config->enable_gpio);
+err_memstate:
+ kfree(drvdata->gpio_states);
+err_memgpio:
+ kfree(drvdata->gpios);
+err_name:
+ kfree(drvdata->desc.name);
+err:
+ kfree(drvdata);
+ return ret;
+}
+
+static int __devexit gpio_regulator_remove(struct platform_device *pdev)
+{
+ struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
+ int ptr;
+
+ regulator_unregister(drvdata->dev);
+
+ for (ptr = 0; ptr < drvdata->nr_gpios; ptr++)
+ gpio_free(drvdata->gpios[ptr]);
+
+ kfree(drvdata->gpio_states);
+ kfree(drvdata->gpios);
+
+ if (gpio_is_valid(drvdata->enable_gpio))
+ gpio_free(drvdata->enable_gpio);
+
+ kfree(drvdata->desc.name);
+ kfree(drvdata);
+
+ return 0;
+}
+
+static struct platform_driver gpio_regulator_driver = {
+ .probe = gpio_regulator_probe,
+ .remove = __devexit_p(gpio_regulator_remove),
+ .driver = {
+ .name = "gpio-regulator",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init gpio_regulator_init(void)
+{
+ return platform_driver_register(&gpio_regulator_driver);
+}
+subsys_initcall(gpio_regulator_init);
+
+static void __exit gpio_regulator_exit(void)
+{
+ platform_driver_unregister(&gpio_regulator_driver);
+}
+module_exit(gpio_regulator_exit);
+
+MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
+MODULE_DESCRIPTION("gpio voltage regulator");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:gpio-regulator");
diff --git a/include/linux/regulator/gpio-regulator.h b/include/linux/regulator/gpio-regulator.h
new file mode 100644
index 0000000..f85d1e5
--- /dev/null
+++ b/include/linux/regulator/gpio-regulator.h
@@ -0,0 +1,84 @@
+/*
+ * 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;
+
+/**
+ * struct gpio_regulator_state - state description
+ * @value: microvolts or microampere
+ * @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.
+ */
+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
+ * @gpio_states: Array of gpio_regulator_state entries describing
+ * the gpio state for specific voltages
+ * @nr_gpio_states: Number of states available
+ * @state_at_boot: State set at boot, default state for the gpios
+ * @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;
+
+ int *gpios;
+ int nr_gpios;
+
+ struct gpio_regulator_state *gpio_states;
+ int nr_gpio_states;
+
+ int state_at_boot;
+
+ enum regulator_type type;
+ struct regulator_init_data *init_data;
+};
+
+#endif
--
1.7.5.4


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