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/consumer.h> 28 #include <linux/slab.h> 29 #include <linux/of.h> 30 #include <linux/regulator/of_regulator.h> 31 #include <linux/regulator/machine.h> 32 33 struct fixed_voltage_data { 34 struct regulator_desc desc; 35 struct regulator_dev *dev; 36 }; 37 38 39 /** 40 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info 41 * @dev: device requesting for fixed_voltage_config 42 * @desc: regulator description 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 const struct regulator_desc *desc) 51 { 52 struct fixed_voltage_config *config; 53 struct device_node *np = dev->of_node; 54 struct regulator_init_data *init_data; 55 56 config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config), 57 GFP_KERNEL); 58 if (!config) 59 return ERR_PTR(-ENOMEM); 60 61 config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc); 62 if (!config->init_data) 63 return ERR_PTR(-EINVAL); 64 65 init_data = config->init_data; 66 init_data->constraints.apply_uV = 0; 67 68 config->supply_name = init_data->constraints.name; 69 if (init_data->constraints.min_uV == init_data->constraints.max_uV) { 70 config->microvolts = init_data->constraints.min_uV; 71 } else { 72 dev_err(dev, 73 "Fixed regulator specified with variable voltages\n"); 74 return ERR_PTR(-EINVAL); 75 } 76 77 if (init_data->constraints.boot_on) 78 config->enabled_at_boot = true; 79 80 of_property_read_u32(np, "startup-delay-us", &config->startup_delay); 81 82 if (of_find_property(np, "vin-supply", NULL)) 83 config->input_supply = "vin"; 84 85 return config; 86 } 87 88 static struct regulator_ops fixed_voltage_ops = { 89 }; 90 91 static int reg_fixed_voltage_probe(struct platform_device *pdev) 92 { 93 struct fixed_voltage_config *config; 94 struct fixed_voltage_data *drvdata; 95 struct regulator_config cfg = { }; 96 enum gpiod_flags gflags; 97 int ret; 98 99 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data), 100 GFP_KERNEL); 101 if (!drvdata) 102 return -ENOMEM; 103 104 if (pdev->dev.of_node) { 105 config = of_get_fixed_voltage_config(&pdev->dev, 106 &drvdata->desc); 107 if (IS_ERR(config)) 108 return PTR_ERR(config); 109 } else { 110 config = dev_get_platdata(&pdev->dev); 111 } 112 113 if (!config) 114 return -ENOMEM; 115 116 drvdata->desc.name = devm_kstrdup(&pdev->dev, 117 config->supply_name, 118 GFP_KERNEL); 119 if (drvdata->desc.name == NULL) { 120 dev_err(&pdev->dev, "Failed to allocate supply name\n"); 121 return -ENOMEM; 122 } 123 drvdata->desc.type = REGULATOR_VOLTAGE; 124 drvdata->desc.owner = THIS_MODULE; 125 drvdata->desc.ops = &fixed_voltage_ops; 126 127 drvdata->desc.enable_time = config->startup_delay; 128 129 if (config->input_supply) { 130 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev, 131 config->input_supply, 132 GFP_KERNEL); 133 if (!drvdata->desc.supply_name) { 134 dev_err(&pdev->dev, 135 "Failed to allocate input supply\n"); 136 return -ENOMEM; 137 } 138 } 139 140 if (config->microvolts) 141 drvdata->desc.n_voltages = 1; 142 143 drvdata->desc.fixed_uV = config->microvolts; 144 145 /* 146 * The signal will be inverted by the GPIO core if flagged so in the 147 * decriptor. 148 */ 149 if (config->enabled_at_boot) 150 gflags = GPIOD_OUT_HIGH; 151 else 152 gflags = GPIOD_OUT_LOW; 153 154 /* 155 * Some fixed regulators share the enable line between two 156 * regulators which makes it necessary to get a handle on the 157 * same descriptor for two different consumers. This will get 158 * the GPIO descriptor, but only the first call will initialize 159 * it so any flags such as inversion or open drain will only 160 * be set up by the first caller and assumed identical on the 161 * next caller. 162 * 163 * FIXME: find a better way to deal with this. 164 */ 165 gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE; 166 167 /* 168 * Do not use devm* here: the regulator core takes over the 169 * lifecycle management of the GPIO descriptor. 170 */ 171 cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags); 172 if (IS_ERR(cfg.ena_gpiod)) 173 return PTR_ERR(cfg.ena_gpiod); 174 175 cfg.dev = &pdev->dev; 176 cfg.init_data = config->init_data; 177 cfg.driver_data = drvdata; 178 cfg.of_node = pdev->dev.of_node; 179 180 drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc, 181 &cfg); 182 if (IS_ERR(drvdata->dev)) { 183 ret = PTR_ERR(drvdata->dev); 184 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret); 185 return ret; 186 } 187 188 platform_set_drvdata(pdev, drvdata); 189 190 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name, 191 drvdata->desc.fixed_uV); 192 193 return 0; 194 } 195 196 #if defined(CONFIG_OF) 197 static const struct of_device_id fixed_of_match[] = { 198 { .compatible = "regulator-fixed", }, 199 {}, 200 }; 201 MODULE_DEVICE_TABLE(of, fixed_of_match); 202 #endif 203 204 static struct platform_driver regulator_fixed_voltage_driver = { 205 .probe = reg_fixed_voltage_probe, 206 .driver = { 207 .name = "reg-fixed-voltage", 208 .of_match_table = of_match_ptr(fixed_of_match), 209 }, 210 }; 211 212 static int __init regulator_fixed_voltage_init(void) 213 { 214 return platform_driver_register(®ulator_fixed_voltage_driver); 215 } 216 subsys_initcall(regulator_fixed_voltage_init); 217 218 static void __exit regulator_fixed_voltage_exit(void) 219 { 220 platform_driver_unregister(®ulator_fixed_voltage_driver); 221 } 222 module_exit(regulator_fixed_voltage_exit); 223 224 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>"); 225 MODULE_DESCRIPTION("Fixed voltage regulator"); 226 MODULE_LICENSE("GPL"); 227 MODULE_ALIAS("platform:reg-fixed-voltage"); 228