diff options
Diffstat (limited to 'drivers/regulator/fixed.c')
| -rw-r--r-- | drivers/regulator/fixed.c | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/drivers/regulator/fixed.c b/drivers/regulator/fixed.c new file mode 100644 index 00000000..40f38030 --- /dev/null +++ b/drivers/regulator/fixed.c @@ -0,0 +1,325 @@ +/* + * 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/fixed.h> +#include <linux/gpio.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/of.h> +#include <linux/of_gpio.h> +#include <linux/regulator/of_regulator.h> +#include <linux/regulator/machine.h> + +struct fixed_voltage_data { + struct regulator_desc desc; + struct regulator_dev *dev; + int microvolts; + int gpio; + unsigned startup_delay; + bool enable_high; + bool is_enabled; +}; + + +/** + * of_get_fixed_voltage_config - extract fixed_voltage_config structure info + * @dev: device requesting for fixed_voltage_config + * + * Populates fixed_voltage_config structure by extracting data from device + * tree node, returns a pointer to the populated structure of NULL if memory + * alloc fails. + */ +static struct fixed_voltage_config * +of_get_fixed_voltage_config(struct device *dev) +{ + struct fixed_voltage_config *config; + struct device_node *np = dev->of_node; + const __be32 *delay; + struct regulator_init_data *init_data; + + config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config), + GFP_KERNEL); + if (!config) + return NULL; + + config->init_data = of_get_regulator_init_data(dev, dev->of_node); + if (!config->init_data) + return NULL; + + init_data = config->init_data; + init_data->constraints.apply_uV = 0; + + config->supply_name = init_data->constraints.name; + if (init_data->constraints.min_uV == init_data->constraints.max_uV) { + config->microvolts = init_data->constraints.min_uV; + } else { + dev_err(dev, + "Fixed regulator specified with variable voltages\n"); + return NULL; + } + + if (init_data->constraints.boot_on) + config->enabled_at_boot = true; + + config->gpio = of_get_named_gpio(np, "gpio", 0); + delay = of_get_property(np, "startup-delay-us", NULL); + if (delay) + config->startup_delay = be32_to_cpu(*delay); + + if (of_find_property(np, "enable-active-high", NULL)) + config->enable_high = true; + + return config; +} + +static int fixed_voltage_is_enabled(struct regulator_dev *dev) +{ + struct fixed_voltage_data *data = rdev_get_drvdata(dev); + + return data->is_enabled; +} + +static int fixed_voltage_enable(struct regulator_dev *dev) +{ + struct fixed_voltage_data *data = rdev_get_drvdata(dev); + + if (gpio_is_valid(data->gpio)) { + gpio_set_value_cansleep(data->gpio, data->enable_high); + data->is_enabled = true; + } + + return 0; +} + +static int fixed_voltage_disable(struct regulator_dev *dev) +{ + struct fixed_voltage_data *data = rdev_get_drvdata(dev); + + if (gpio_is_valid(data->gpio)) { + gpio_set_value_cansleep(data->gpio, !data->enable_high); + data->is_enabled = false; + } + + return 0; +} + +static int fixed_voltage_enable_time(struct regulator_dev *dev) +{ + struct fixed_voltage_data *data = rdev_get_drvdata(dev); + + return data->startup_delay; +} + +static int fixed_voltage_get_voltage(struct regulator_dev *dev) +{ + struct fixed_voltage_data *data = rdev_get_drvdata(dev); + + if (data->microvolts) + return data->microvolts; + else + return -EINVAL; +} + +static int fixed_voltage_list_voltage(struct regulator_dev *dev, + unsigned selector) +{ + struct fixed_voltage_data *data = rdev_get_drvdata(dev); + + if (selector != 0) + return -EINVAL; + + return data->microvolts; +} + +static struct regulator_ops fixed_voltage_ops = { + .is_enabled = fixed_voltage_is_enabled, + .enable = fixed_voltage_enable, + .disable = fixed_voltage_disable, + .enable_time = fixed_voltage_enable_time, + .get_voltage = fixed_voltage_get_voltage, + .list_voltage = fixed_voltage_list_voltage, +}; + +static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev) +{ + struct fixed_voltage_config *config; + struct fixed_voltage_data *drvdata; + int ret; + + if (pdev->dev.of_node) + config = of_get_fixed_voltage_config(&pdev->dev); + else + config = pdev->dev.platform_data; + + if (!config) + return -ENOMEM; + + drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL); + if (drvdata == NULL) { + dev_err(&pdev->dev, "Failed to allocate device data\n"); + ret = -ENOMEM; + goto err; + } + + 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->desc.type = REGULATOR_VOLTAGE; + drvdata->desc.owner = THIS_MODULE; + drvdata->desc.ops = &fixed_voltage_ops; + + if (config->microvolts) + drvdata->desc.n_voltages = 1; + + drvdata->microvolts = config->microvolts; + drvdata->gpio = config->gpio; + drvdata->startup_delay = config->startup_delay; + + if (gpio_is_valid(config->gpio)) { + drvdata->enable_high = config->enable_high; + + /* FIXME: Remove below print warning + * + * config->gpio must be set to -EINVAL by platform code if + * GPIO control is not required. However, early adopters + * not requiring GPIO control may forget to initialize + * config->gpio to -EINVAL. This will cause GPIO 0 to be used + * for GPIO control. + * + * This warning will be removed once there are a couple of users + * for this driver. + */ + if (!config->gpio) + dev_warn(&pdev->dev, + "using GPIO 0 for regulator enable control\n"); + + ret = gpio_request(config->gpio, config->supply_name); + if (ret) { + dev_err(&pdev->dev, + "Could not obtain regulator enable GPIO %d: %d\n", + config->gpio, ret); + goto err_name; + } + + /* 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->gpio, ret); + if (ret) { + dev_err(&pdev->dev, + "Could not configure regulator enable GPIO %d direction: %d\n", + config->gpio, ret); + goto err_gpio; + } + + } else { + /* Regulator without GPIO control is considered + * always enabled + */ + drvdata->is_enabled = true; + } + + drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev, + config->init_data, drvdata, + pdev->dev.of_node); + if (IS_ERR(drvdata->dev)) { + ret = PTR_ERR(drvdata->dev); + dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret); + goto err_gpio; + } + + platform_set_drvdata(pdev, drvdata); + + dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name, + drvdata->microvolts); + + return 0; + +err_gpio: + if (gpio_is_valid(config->gpio)) + gpio_free(config->gpio); +err_name: + kfree(drvdata->desc.name); +err: + kfree(drvdata); + return ret; +} + +static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev) +{ + struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev); + + regulator_unregister(drvdata->dev); + if (gpio_is_valid(drvdata->gpio)) + gpio_free(drvdata->gpio); + kfree(drvdata->desc.name); + kfree(drvdata); + + return 0; +} + +#if defined(CONFIG_OF) +static const struct of_device_id fixed_of_match[] __devinitconst = { + { .compatible = "regulator-fixed", }, + {}, +}; +MODULE_DEVICE_TABLE(of, fixed_of_match); +#else +#define fixed_of_match NULL +#endif + +static struct platform_driver regulator_fixed_voltage_driver = { + .probe = reg_fixed_voltage_probe, + .remove = __devexit_p(reg_fixed_voltage_remove), + .driver = { + .name = "reg-fixed-voltage", + .owner = THIS_MODULE, + .of_match_table = fixed_of_match, + }, +}; + +static int __init regulator_fixed_voltage_init(void) +{ + return platform_driver_register(®ulator_fixed_voltage_driver); +} +subsys_initcall(regulator_fixed_voltage_init); + +static void __exit regulator_fixed_voltage_exit(void) +{ + platform_driver_unregister(®ulator_fixed_voltage_driver); +} +module_exit(regulator_fixed_voltage_exit); + +MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>"); +MODULE_DESCRIPTION("Fixed voltage regulator"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:reg-fixed-voltage"); |