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 * @desc: regulator description 44 * 45 * Populates fixed_voltage_config structure by extracting data from device 46 * tree node, returns a pointer to the populated structure of NULL if memory 47 * alloc fails. 48 */ 49 static struct fixed_voltage_config * 50 of_get_fixed_voltage_config(struct device *dev, 51 const struct regulator_desc *desc) 52 { 53 struct fixed_voltage_config *config; 54 struct device_node *np = dev->of_node; 55 struct regulator_init_data *init_data; 56 57 config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config), 58 GFP_KERNEL); 59 if (!config) 60 return ERR_PTR(-ENOMEM); 61 62 config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc); 63 if (!config->init_data) 64 return ERR_PTR(-EINVAL); 65 66 init_data = config->init_data; 67 init_data->constraints.apply_uV = 0; 68 69 config->supply_name = init_data->constraints.name; 70 if (init_data->constraints.min_uV == init_data->constraints.max_uV) { 71 config->microvolts = init_data->constraints.min_uV; 72 } else { 73 dev_err(dev, 74 "Fixed regulator specified with variable voltages\n"); 75 return ERR_PTR(-EINVAL); 76 } 77 78 if (init_data->constraints.boot_on) 79 config->enabled_at_boot = true; 80 81 config->gpio = of_get_named_gpio(np, "gpio", 0); 82 if ((config->gpio < 0) && (config->gpio != -ENOENT)) 83 return ERR_PTR(config->gpio); 84 85 of_property_read_u32(np, "startup-delay-us", &config->startup_delay); 86 87 config->enable_high = of_property_read_bool(np, "enable-active-high"); 88 config->gpio_is_open_drain = of_property_read_bool(np, 89 "gpio-open-drain"); 90 91 if (of_find_property(np, "vin-supply", NULL)) 92 config->input_supply = "vin"; 93 94 return config; 95 } 96 97 static struct regulator_ops fixed_voltage_ops = { 98 }; 99 100 static int reg_fixed_voltage_probe(struct platform_device *pdev) 101 { 102 struct fixed_voltage_config *config; 103 struct fixed_voltage_data *drvdata; 104 struct regulator_config cfg = { }; 105 int ret; 106 107 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data), 108 GFP_KERNEL); 109 if (!drvdata) 110 return -ENOMEM; 111 112 if (pdev->dev.of_node) { 113 config = of_get_fixed_voltage_config(&pdev->dev, 114 &drvdata->desc); 115 if (IS_ERR(config)) 116 return PTR_ERR(config); 117 } else { 118 config = dev_get_platdata(&pdev->dev); 119 } 120 121 if (!config) 122 return -ENOMEM; 123 124 drvdata->desc.name = devm_kstrdup(&pdev->dev, 125 config->supply_name, 126 GFP_KERNEL); 127 if (drvdata->desc.name == NULL) { 128 dev_err(&pdev->dev, "Failed to allocate supply name\n"); 129 return -ENOMEM; 130 } 131 drvdata->desc.type = REGULATOR_VOLTAGE; 132 drvdata->desc.owner = THIS_MODULE; 133 drvdata->desc.ops = &fixed_voltage_ops; 134 135 drvdata->desc.enable_time = config->startup_delay; 136 137 if (config->input_supply) { 138 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev, 139 config->input_supply, 140 GFP_KERNEL); 141 if (!drvdata->desc.supply_name) { 142 dev_err(&pdev->dev, 143 "Failed to allocate input supply\n"); 144 return -ENOMEM; 145 } 146 } 147 148 if (config->microvolts) 149 drvdata->desc.n_voltages = 1; 150 151 drvdata->desc.fixed_uV = config->microvolts; 152 153 if (gpio_is_valid(config->gpio)) { 154 cfg.ena_gpio = config->gpio; 155 if (pdev->dev.of_node) 156 cfg.ena_gpio_initialized = true; 157 } 158 cfg.ena_gpio_invert = !config->enable_high; 159 if (config->enabled_at_boot) { 160 if (config->enable_high) 161 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH; 162 else 163 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW; 164 } else { 165 if (config->enable_high) 166 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW; 167 else 168 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH; 169 } 170 if (config->gpio_is_open_drain) 171 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN; 172 173 cfg.dev = &pdev->dev; 174 cfg.init_data = config->init_data; 175 cfg.driver_data = drvdata; 176 cfg.of_node = pdev->dev.of_node; 177 178 drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc, 179 &cfg); 180 if (IS_ERR(drvdata->dev)) { 181 ret = PTR_ERR(drvdata->dev); 182 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret); 183 return ret; 184 } 185 186 platform_set_drvdata(pdev, drvdata); 187 188 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name, 189 drvdata->desc.fixed_uV); 190 191 return 0; 192 } 193 194 #if defined(CONFIG_OF) 195 static const struct of_device_id fixed_of_match[] = { 196 { .compatible = "regulator-fixed", }, 197 {}, 198 }; 199 MODULE_DEVICE_TABLE(of, fixed_of_match); 200 #endif 201 202 static struct platform_driver regulator_fixed_voltage_driver = { 203 .probe = reg_fixed_voltage_probe, 204 .driver = { 205 .name = "reg-fixed-voltage", 206 .of_match_table = of_match_ptr(fixed_of_match), 207 }, 208 }; 209 210 static int __init regulator_fixed_voltage_init(void) 211 { 212 return platform_driver_register(®ulator_fixed_voltage_driver); 213 } 214 subsys_initcall(regulator_fixed_voltage_init); 215 216 static void __exit regulator_fixed_voltage_exit(void) 217 { 218 platform_driver_unregister(®ulator_fixed_voltage_driver); 219 } 220 module_exit(regulator_fixed_voltage_exit); 221 222 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>"); 223 MODULE_DESCRIPTION("Fixed voltage regulator"); 224 MODULE_LICENSE("GPL"); 225 MODULE_ALIAS("platform:reg-fixed-voltage"); 226