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/module.h> 24 #include <linux/platform_device.h> 25 #include <linux/regulator/driver.h> 26 #include <linux/regulator/fixed.h> 27 #include <linux/gpio.h> 28 #include <linux/slab.h> 29 #include <linux/of.h> 30 #include <linux/of_gpio.h> 31 #include <linux/regulator/of_regulator.h> 32 #include <linux/regulator/machine.h> 33 34 struct fixed_voltage_data { 35 struct regulator_desc desc; 36 struct regulator_dev *dev; 37 }; 38 39 40 /** 41 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info 42 * @dev: device requesting for fixed_voltage_config 43 * 44 * Populates fixed_voltage_config structure by extracting data from device 45 * tree node, returns a pointer to the populated structure of NULL if memory 46 * alloc fails. 47 */ 48 static struct fixed_voltage_config * 49 of_get_fixed_voltage_config(struct device *dev) 50 { 51 struct fixed_voltage_config *config; 52 struct device_node *np = dev->of_node; 53 struct regulator_init_data *init_data; 54 55 config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config), 56 GFP_KERNEL); 57 if (!config) 58 return ERR_PTR(-ENOMEM); 59 60 config->init_data = of_get_regulator_init_data(dev, dev->of_node); 61 if (!config->init_data) 62 return ERR_PTR(-EINVAL); 63 64 init_data = config->init_data; 65 init_data->constraints.apply_uV = 0; 66 67 config->supply_name = init_data->constraints.name; 68 if (init_data->constraints.min_uV == init_data->constraints.max_uV) { 69 config->microvolts = init_data->constraints.min_uV; 70 } else { 71 dev_err(dev, 72 "Fixed regulator specified with variable voltages\n"); 73 return ERR_PTR(-EINVAL); 74 } 75 76 if (init_data->constraints.boot_on) 77 config->enabled_at_boot = true; 78 79 config->gpio = of_get_named_gpio(np, "gpio", 0); 80 /* 81 * of_get_named_gpio() currently returns ENODEV rather than 82 * EPROBE_DEFER. This code attempts to be compatible with both 83 * for now; the ENODEV check can be removed once the API is fixed. 84 * of_get_named_gpio() doesn't differentiate between a missing 85 * property (which would be fine here, since the GPIO is optional) 86 * and some other error. Patches have been posted for both issues. 87 * Once they are check in, we should replace this with: 88 * if (config->gpio < 0 && config->gpio != -ENOENT) 89 */ 90 if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER)) 91 return ERR_PTR(-EPROBE_DEFER); 92 93 of_property_read_u32(np, "startup-delay-us", &config->startup_delay); 94 95 config->enable_high = of_property_read_bool(np, "enable-active-high"); 96 config->gpio_is_open_drain = of_property_read_bool(np, 97 "gpio-open-drain"); 98 99 if (of_find_property(np, "vin-supply", NULL)) 100 config->input_supply = "vin"; 101 102 return config; 103 } 104 105 static struct regulator_ops fixed_voltage_ops = { 106 }; 107 108 static int reg_fixed_voltage_probe(struct platform_device *pdev) 109 { 110 struct fixed_voltage_config *config; 111 struct fixed_voltage_data *drvdata; 112 struct regulator_config cfg = { }; 113 int ret; 114 115 if (pdev->dev.of_node) { 116 config = of_get_fixed_voltage_config(&pdev->dev); 117 if (IS_ERR(config)) 118 return PTR_ERR(config); 119 } else { 120 config = dev_get_platdata(&pdev->dev); 121 } 122 123 if (!config) 124 return -ENOMEM; 125 126 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data), 127 GFP_KERNEL); 128 if (!drvdata) 129 return -ENOMEM; 130 131 drvdata->desc.name = devm_kstrdup(&pdev->dev, 132 config->supply_name, 133 GFP_KERNEL); 134 if (drvdata->desc.name == NULL) { 135 dev_err(&pdev->dev, "Failed to allocate supply name\n"); 136 return -ENOMEM; 137 } 138 drvdata->desc.type = REGULATOR_VOLTAGE; 139 drvdata->desc.owner = THIS_MODULE; 140 drvdata->desc.ops = &fixed_voltage_ops; 141 142 drvdata->desc.enable_time = config->startup_delay; 143 144 if (config->input_supply) { 145 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev, 146 config->input_supply, 147 GFP_KERNEL); 148 if (!drvdata->desc.supply_name) { 149 dev_err(&pdev->dev, 150 "Failed to allocate input supply\n"); 151 return -ENOMEM; 152 } 153 } 154 155 if (config->microvolts) 156 drvdata->desc.n_voltages = 1; 157 158 drvdata->desc.fixed_uV = config->microvolts; 159 160 if (config->gpio >= 0) 161 cfg.ena_gpio = config->gpio; 162 cfg.ena_gpio_invert = !config->enable_high; 163 if (config->enabled_at_boot) { 164 if (config->enable_high) 165 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH; 166 else 167 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW; 168 } else { 169 if (config->enable_high) 170 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW; 171 else 172 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH; 173 } 174 if (config->gpio_is_open_drain) 175 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN; 176 177 cfg.dev = &pdev->dev; 178 cfg.init_data = config->init_data; 179 cfg.driver_data = drvdata; 180 cfg.of_node = pdev->dev.of_node; 181 182 drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc, 183 &cfg); 184 if (IS_ERR(drvdata->dev)) { 185 ret = PTR_ERR(drvdata->dev); 186 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret); 187 return ret; 188 } 189 190 platform_set_drvdata(pdev, drvdata); 191 192 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name, 193 drvdata->desc.fixed_uV); 194 195 return 0; 196 } 197 198 #if defined(CONFIG_OF) 199 static const struct of_device_id fixed_of_match[] = { 200 { .compatible = "regulator-fixed", }, 201 {}, 202 }; 203 MODULE_DEVICE_TABLE(of, fixed_of_match); 204 #endif 205 206 static struct platform_driver regulator_fixed_voltage_driver = { 207 .probe = reg_fixed_voltage_probe, 208 .driver = { 209 .name = "reg-fixed-voltage", 210 .owner = THIS_MODULE, 211 .of_match_table = of_match_ptr(fixed_of_match), 212 }, 213 }; 214 215 static int __init regulator_fixed_voltage_init(void) 216 { 217 return platform_driver_register(®ulator_fixed_voltage_driver); 218 } 219 subsys_initcall(regulator_fixed_voltage_init); 220 221 static void __exit regulator_fixed_voltage_exit(void) 222 { 223 platform_driver_unregister(®ulator_fixed_voltage_driver); 224 } 225 module_exit(regulator_fixed_voltage_exit); 226 227 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>"); 228 MODULE_DESCRIPTION("Fixed voltage regulator"); 229 MODULE_LICENSE("GPL"); 230 MODULE_ALIAS("platform:reg-fixed-voltage"); 231