regulator: Add driver for gpio-controlled regulators
Heiko Stübner [Wed, 5 Oct 2011 10:27:05 +0000 (12:27 +0200)]
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>
(cherry picked from commit 3f0292ae8bb100cc8f96106a3de277df48134887)

regulator: Add module.h include to gpio-regulator

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
(cherry picked from commit ecc37edf7b670616a9dc78a0bdd4911a22d551ec)

regulator: Fix compile break due to missing arguments to regulator_register

The commit 2c043bcbf287 ("regulator: pass additional of_node to
regulator_register()") caused a compile break because it missed
updating the regulator_register() call in gpio-regulator.c with
the additional parameter (NULL).

The compile break as reported by Stephen Rothwell with the
x86_64 allmodconfig looked like this

drivers/regulator/gpio-regulator.c: In function 'gpio_regulator_probe':
drivers/regulator/gpio-regulator.c:287:8: error: too few arguments to function 'regulator_register'
include/linux/regulator/driver.h:215:23: note: declared here

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
(cherry picked from commit 156843470c4b9ea9698cc245d2cff769b3784088)
Change-Id: I912886aae825ca440f4ad3e7a33fe4e84bde4e1b
Reviewed-on: http://git-master/r/74924
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>
Tested-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-on: http://git-master/r/75547
Reviewed-by: Varun Wadekar <vwadekar@nvidia.com>
Tested-by: Varun Wadekar <vwadekar@nvidia.com>

drivers/regulator/Kconfig
drivers/regulator/Makefile
drivers/regulator/gpio-regulator.c [new file with mode: 0644]
include/linux/regulator/gpio-regulator.h [new file with mode: 0644]

index 8f52d9c..09d2150 100644 (file)
@@ -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
index 4337283..6f54bfd 100644 (file)
@@ -8,6 +8,7 @@ obj-$(CONFIG_REGULATOR_FIXED_VOLTAGE) += fixed.o
 obj-$(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 (file)
index 0000000..42e1cb1
--- /dev/null
@@ -0,0 +1,358 @@
+/*
+ * 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/module.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;
+
+       struct gpio *gpios;
+       int nr_gpios;
+
+       struct gpio_regulator_state *states;
+       int nr_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_states; ptr++)
+               if (data->states[ptr].gpios == data->state)
+                       return data->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_states; ptr++)
+               if (data->states[ptr].value >= min &&
+                   data->states[ptr].value <= max)
+                       target = data->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].gpio, 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_states)
+               return -EINVAL;
+
+       return data->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 = kmemdup(config->gpios,
+                                config->nr_gpios * sizeof(struct gpio),
+                                GFP_KERNEL);
+       if (drvdata->gpios == NULL) {
+               dev_err(&pdev->dev, "Failed to allocate gpio data\n");
+               ret = -ENOMEM;
+               goto err_name;
+       }
+
+       drvdata->states = kmemdup(config->states,
+                                 config->nr_states *
+                                        sizeof(struct gpio_regulator_state),
+                                 GFP_KERNEL);
+       if (drvdata->states == NULL) {
+               dev_err(&pdev->dev, "Failed to allocate state data\n");
+               ret = -ENOMEM;
+               goto err_memgpio;
+       }
+       drvdata->nr_states = config->nr_states;
+
+       drvdata->desc.owner = THIS_MODULE;
+
+       /* handle regulator type*/
+       switch (config->type) {
+       case REGULATOR_VOLTAGE:
+               drvdata->desc.type = REGULATOR_VOLTAGE;
+               drvdata->desc.ops = &gpio_regulator_voltage_ops;
+               drvdata->desc.n_voltages = config->nr_states;
+               break;
+       case REGULATOR_CURRENT:
+               drvdata->desc.type = 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
+                */
+               if (config->enabled_at_boot) {
+                       drvdata->is_enabled = true;
+                       ret = gpio_direction_output(config->enable_gpio,
+                                                   config->enable_high);
+               } else {
+                       drvdata->is_enabled = false;
+                       ret = gpio_direction_output(config->enable_gpio,
+                                                   !config->enable_high);
+               }
+
+               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;
+       ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
+       if (ret) {
+               dev_err(&pdev->dev,
+                  "Could not obtain regulator setting GPIOs: %d\n", ret);
+               goto err_enablegpio;
+       }
+
+       /* build initial state from gpio init data. */
+       state = 0;
+       for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
+               if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
+                       state |= (1 << ptr);
+       }
+       drvdata->state = state;
+
+       drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
+                                         config->init_data, drvdata, NULL);
+       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:
+       gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
+err_enablegpio:
+       if (gpio_is_valid(config->enable_gpio))
+               gpio_free(config->enable_gpio);
+err_memstate:
+       kfree(drvdata->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);
+
+       regulator_unregister(drvdata->dev);
+
+       gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
+
+       kfree(drvdata->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 (file)
index 0000000..19fbd26
--- /dev/null
@@ -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