| 1 | /* |
| 2 | * fixed.c |
| 3 | * |
| 4 | * Copyright 2008 Wolfson Microelectronics PLC. |
| 5 | * |
| 6 | * Author: Mark Brown <broonie@opensource.wolfsonmicro.com> |
| 7 | * |
| 8 | * Copyright (c) 2009 Nokia Corporation |
| 9 | * Roger Quadros <ext-roger.quadros@nokia.com> |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or |
| 12 | * modify it under the terms of the GNU General Public License as |
| 13 | * published by the Free Software Foundation; either version 2 of the |
| 14 | * License, or (at your option) any later version. |
| 15 | * |
| 16 | * This is useful for systems with mixed controllable and |
| 17 | * non-controllable regulators, as well as for allowing testing on |
| 18 | * systems with no controllable regulators. |
| 19 | */ |
| 20 | |
| 21 | #include <linux/err.h> |
| 22 | #include <linux/mutex.h> |
| 23 | #include <linux/platform_device.h> |
| 24 | #include <linux/regulator/driver.h> |
| 25 | #include <linux/regulator/fixed.h> |
| 26 | #include <linux/gpio.h> |
| 27 | #include <linux/delay.h> |
| 28 | #include <linux/slab.h> |
| 29 | |
| 30 | struct fixed_voltage_data { |
| 31 | struct regulator_desc desc; |
| 32 | struct regulator_dev *dev; |
| 33 | int microvolts; |
| 34 | int gpio; |
| 35 | unsigned startup_delay; |
| 36 | bool enable_high; |
| 37 | bool is_enabled; |
| 38 | }; |
| 39 | |
| 40 | static int fixed_voltage_is_enabled(struct regulator_dev *dev) |
| 41 | { |
| 42 | struct fixed_voltage_data *data = rdev_get_drvdata(dev); |
| 43 | |
| 44 | return data->is_enabled; |
| 45 | } |
| 46 | |
| 47 | static int fixed_voltage_enable(struct regulator_dev *dev) |
| 48 | { |
| 49 | struct fixed_voltage_data *data = rdev_get_drvdata(dev); |
| 50 | |
| 51 | if (gpio_is_valid(data->gpio)) { |
| 52 | gpio_set_value_cansleep(data->gpio, data->enable_high); |
| 53 | data->is_enabled = true; |
| 54 | } |
| 55 | |
| 56 | return 0; |
| 57 | } |
| 58 | |
| 59 | static int fixed_voltage_disable(struct regulator_dev *dev) |
| 60 | { |
| 61 | struct fixed_voltage_data *data = rdev_get_drvdata(dev); |
| 62 | |
| 63 | if (gpio_is_valid(data->gpio)) { |
| 64 | gpio_set_value_cansleep(data->gpio, !data->enable_high); |
| 65 | data->is_enabled = false; |
| 66 | } |
| 67 | |
| 68 | return 0; |
| 69 | } |
| 70 | |
| 71 | static int fixed_voltage_enable_time(struct regulator_dev *dev) |
| 72 | { |
| 73 | struct fixed_voltage_data *data = rdev_get_drvdata(dev); |
| 74 | |
| 75 | return data->startup_delay; |
| 76 | } |
| 77 | |
| 78 | static int fixed_voltage_get_voltage(struct regulator_dev *dev) |
| 79 | { |
| 80 | struct fixed_voltage_data *data = rdev_get_drvdata(dev); |
| 81 | |
| 82 | return data->microvolts; |
| 83 | } |
| 84 | |
| 85 | static int fixed_voltage_list_voltage(struct regulator_dev *dev, |
| 86 | unsigned selector) |
| 87 | { |
| 88 | struct fixed_voltage_data *data = rdev_get_drvdata(dev); |
| 89 | |
| 90 | if (selector != 0) |
| 91 | return -EINVAL; |
| 92 | |
| 93 | return data->microvolts; |
| 94 | } |
| 95 | |
| 96 | static struct regulator_ops fixed_voltage_ops = { |
| 97 | .is_enabled = fixed_voltage_is_enabled, |
| 98 | .enable = fixed_voltage_enable, |
| 99 | .disable = fixed_voltage_disable, |
| 100 | .enable_time = fixed_voltage_enable_time, |
| 101 | .get_voltage = fixed_voltage_get_voltage, |
| 102 | .list_voltage = fixed_voltage_list_voltage, |
| 103 | }; |
| 104 | |
| 105 | static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev) |
| 106 | { |
| 107 | struct fixed_voltage_config *config = pdev->dev.platform_data; |
| 108 | struct fixed_voltage_data *drvdata; |
| 109 | int ret; |
| 110 | |
| 111 | drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL); |
| 112 | if (drvdata == NULL) { |
| 113 | dev_err(&pdev->dev, "Failed to allocate device data\n"); |
| 114 | ret = -ENOMEM; |
| 115 | goto err; |
| 116 | } |
| 117 | |
| 118 | drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL); |
| 119 | if (drvdata->desc.name == NULL) { |
| 120 | dev_err(&pdev->dev, "Failed to allocate supply name\n"); |
| 121 | ret = -ENOMEM; |
| 122 | goto err; |
| 123 | } |
| 124 | drvdata->desc.type = REGULATOR_VOLTAGE; |
| 125 | drvdata->desc.owner = THIS_MODULE; |
| 126 | drvdata->desc.ops = &fixed_voltage_ops; |
| 127 | drvdata->desc.n_voltages = 1; |
| 128 | |
| 129 | drvdata->microvolts = config->microvolts; |
| 130 | drvdata->gpio = config->gpio; |
| 131 | drvdata->startup_delay = config->startup_delay; |
| 132 | |
| 133 | if (gpio_is_valid(config->gpio)) { |
| 134 | drvdata->enable_high = config->enable_high; |
| 135 | |
| 136 | /* FIXME: Remove below print warning |
| 137 | * |
| 138 | * config->gpio must be set to -EINVAL by platform code if |
| 139 | * GPIO control is not required. However, early adopters |
| 140 | * not requiring GPIO control may forget to initialize |
| 141 | * config->gpio to -EINVAL. This will cause GPIO 0 to be used |
| 142 | * for GPIO control. |
| 143 | * |
| 144 | * This warning will be removed once there are a couple of users |
| 145 | * for this driver. |
| 146 | */ |
| 147 | if (!config->gpio) |
| 148 | dev_warn(&pdev->dev, |
| 149 | "using GPIO 0 for regulator enable control\n"); |
| 150 | |
| 151 | ret = gpio_request(config->gpio, config->supply_name); |
| 152 | if (ret) { |
| 153 | dev_err(&pdev->dev, |
| 154 | "Could not obtain regulator enable GPIO %d: %d\n", |
| 155 | config->gpio, ret); |
| 156 | goto err_name; |
| 157 | } |
| 158 | |
| 159 | /* set output direction without changing state |
| 160 | * to prevent glitch |
| 161 | */ |
| 162 | drvdata->is_enabled = config->enabled_at_boot; |
| 163 | ret = drvdata->is_enabled ? |
| 164 | config->enable_high : !config->enable_high; |
| 165 | |
| 166 | ret = gpio_direction_output(config->gpio, ret); |
| 167 | if (ret) { |
| 168 | dev_err(&pdev->dev, |
| 169 | "Could not configure regulator enable GPIO %d direction: %d\n", |
| 170 | config->gpio, ret); |
| 171 | goto err_gpio; |
| 172 | } |
| 173 | |
| 174 | } else { |
| 175 | /* Regulator without GPIO control is considered |
| 176 | * always enabled |
| 177 | */ |
| 178 | drvdata->is_enabled = true; |
| 179 | } |
| 180 | |
| 181 | drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev, |
| 182 | config->init_data, drvdata); |
| 183 | if (IS_ERR(drvdata->dev)) { |
| 184 | ret = PTR_ERR(drvdata->dev); |
| 185 | dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret); |
| 186 | goto err_gpio; |
| 187 | } |
| 188 | |
| 189 | platform_set_drvdata(pdev, drvdata); |
| 190 | |
| 191 | dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name, |
| 192 | drvdata->microvolts); |
| 193 | |
| 194 | return 0; |
| 195 | |
| 196 | err_gpio: |
| 197 | if (gpio_is_valid(config->gpio)) |
| 198 | gpio_free(config->gpio); |
| 199 | err_name: |
| 200 | kfree(drvdata->desc.name); |
| 201 | err: |
| 202 | kfree(drvdata); |
| 203 | return ret; |
| 204 | } |
| 205 | |
| 206 | static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev) |
| 207 | { |
| 208 | struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev); |
| 209 | |
| 210 | regulator_unregister(drvdata->dev); |
| 211 | if (gpio_is_valid(drvdata->gpio)) |
| 212 | gpio_free(drvdata->gpio); |
| 213 | kfree(drvdata->desc.name); |
| 214 | kfree(drvdata); |
| 215 | |
| 216 | return 0; |
| 217 | } |
| 218 | |
| 219 | static struct platform_driver regulator_fixed_voltage_driver = { |
| 220 | .probe = reg_fixed_voltage_probe, |
| 221 | .remove = __devexit_p(reg_fixed_voltage_remove), |
| 222 | .driver = { |
| 223 | .name = "reg-fixed-voltage", |
| 224 | .owner = THIS_MODULE, |
| 225 | }, |
| 226 | }; |
| 227 | |
| 228 | static int __init regulator_fixed_voltage_init(void) |
| 229 | { |
| 230 | return platform_driver_register(®ulator_fixed_voltage_driver); |
| 231 | } |
| 232 | subsys_initcall(regulator_fixed_voltage_init); |
| 233 | |
| 234 | static void __exit regulator_fixed_voltage_exit(void) |
| 235 | { |
| 236 | platform_driver_unregister(®ulator_fixed_voltage_driver); |
| 237 | } |
| 238 | module_exit(regulator_fixed_voltage_exit); |
| 239 | |
| 240 | MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>"); |
| 241 | MODULE_DESCRIPTION("Fixed voltage regulator"); |
| 242 | MODULE_LICENSE("GPL"); |
| 243 | MODULE_ALIAS("platform:reg-fixed-voltage"); |