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 /* 83 * of_get_named_gpio() currently returns ENODEV rather than 84 * EPROBE_DEFER. This code attempts to be compatible with both 85 * for now; the ENODEV check can be removed once the API is fixed. 86 * of_get_named_gpio() doesn't differentiate between a missing 87 * property (which would be fine here, since the GPIO is optional) 88 * and some other error. Patches have been posted for both issues. 89 * Once they are check in, we should replace this with: 90 * if (config->gpio < 0 && config->gpio != -ENOENT) 91 */ 92 if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER)) 93 return ERR_PTR(-EPROBE_DEFER); 94 95 of_property_read_u32(np, "startup-delay-us", &config->startup_delay); 96 97 config->enable_high = of_property_read_bool(np, "enable-active-high"); 98 config->gpio_is_open_drain = of_property_read_bool(np, 99 "gpio-open-drain"); 100 101 if (of_find_property(np, "vin-supply", NULL)) 102 config->input_supply = "vin"; 103 104 return config; 105 } 106 107 static struct regulator_ops fixed_voltage_ops = { 108 }; 109 110 static int reg_fixed_voltage_probe(struct platform_device *pdev) 111 { 112 struct fixed_voltage_config *config; 113 struct fixed_voltage_data *drvdata; 114 struct regulator_config cfg = { }; 115 int ret; 116 117 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data), 118 GFP_KERNEL); 119 if (!drvdata) 120 return -ENOMEM; 121 122 if (pdev->dev.of_node) { 123 config = of_get_fixed_voltage_config(&pdev->dev, 124 &drvdata->desc); 125 if (IS_ERR(config)) 126 return PTR_ERR(config); 127 } else { 128 config = dev_get_platdata(&pdev->dev); 129 } 130 131 if (!config) 132 return -ENOMEM; 133 134 drvdata->desc.name = devm_kstrdup(&pdev->dev, 135 config->supply_name, 136 GFP_KERNEL); 137 if (drvdata->desc.name == NULL) { 138 dev_err(&pdev->dev, "Failed to allocate supply name\n"); 139 return -ENOMEM; 140 } 141 drvdata->desc.type = REGULATOR_VOLTAGE; 142 drvdata->desc.owner = THIS_MODULE; 143 drvdata->desc.ops = &fixed_voltage_ops; 144 145 drvdata->desc.enable_time = config->startup_delay; 146 147 if (config->input_supply) { 148 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev, 149 config->input_supply, 150 GFP_KERNEL); 151 if (!drvdata->desc.supply_name) { 152 dev_err(&pdev->dev, 153 "Failed to allocate input supply\n"); 154 return -ENOMEM; 155 } 156 } 157 158 if (config->microvolts) 159 drvdata->desc.n_voltages = 1; 160 161 drvdata->desc.fixed_uV = config->microvolts; 162 163 if (gpio_is_valid(config->gpio)) { 164 cfg.ena_gpio = config->gpio; 165 if (pdev->dev.of_node) 166 cfg.ena_gpio_initialized = true; 167 } 168 cfg.ena_gpio_invert = !config->enable_high; 169 if (config->enabled_at_boot) { 170 if (config->enable_high) 171 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH; 172 else 173 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW; 174 } else { 175 if (config->enable_high) 176 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW; 177 else 178 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH; 179 } 180 if (config->gpio_is_open_drain) 181 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN; 182 183 cfg.dev = &pdev->dev; 184 cfg.init_data = config->init_data; 185 cfg.driver_data = drvdata; 186 cfg.of_node = pdev->dev.of_node; 187 188 drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc, 189 &cfg); 190 if (IS_ERR(drvdata->dev)) { 191 ret = PTR_ERR(drvdata->dev); 192 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret); 193 return ret; 194 } 195 196 platform_set_drvdata(pdev, drvdata); 197 198 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name, 199 drvdata->desc.fixed_uV); 200 201 return 0; 202 } 203 204 #if defined(CONFIG_OF) 205 static const struct of_device_id fixed_of_match[] = { 206 { .compatible = "regulator-fixed", }, 207 {}, 208 }; 209 MODULE_DEVICE_TABLE(of, fixed_of_match); 210 #endif 211 212 static struct platform_driver regulator_fixed_voltage_driver = { 213 .probe = reg_fixed_voltage_probe, 214 .driver = { 215 .name = "reg-fixed-voltage", 216 .of_match_table = of_match_ptr(fixed_of_match), 217 }, 218 }; 219 220 static int __init regulator_fixed_voltage_init(void) 221 { 222 return platform_driver_register(®ulator_fixed_voltage_driver); 223 } 224 subsys_initcall(regulator_fixed_voltage_init); 225 226 static void __exit regulator_fixed_voltage_exit(void) 227 { 228 platform_driver_unregister(®ulator_fixed_voltage_driver); 229 } 230 module_exit(regulator_fixed_voltage_exit); 231 232 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>"); 233 MODULE_DESCRIPTION("Fixed voltage regulator"); 234 MODULE_LICENSE("GPL"); 235 MODULE_ALIAS("platform:reg-fixed-voltage"); 236