1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * fixed.c 4 * 5 * Copyright 2008 Wolfson Microelectronics PLC. 6 * 7 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com> 8 * 9 * Copyright (c) 2009 Nokia Corporation 10 * Roger Quadros <ext-roger.quadros@nokia.com> 11 * 12 * This is useful for systems with mixed controllable and 13 * non-controllable regulators, as well as for allowing testing on 14 * systems with no controllable regulators. 15 */ 16 17 #include <linux/err.h> 18 #include <linux/mutex.h> 19 #include <linux/module.h> 20 #include <linux/platform_device.h> 21 #include <linux/regulator/driver.h> 22 #include <linux/regulator/fixed.h> 23 #include <linux/gpio/consumer.h> 24 #include <linux/slab.h> 25 #include <linux/of.h> 26 #include <linux/of_device.h> 27 #include <linux/regulator/of_regulator.h> 28 #include <linux/regulator/machine.h> 29 #include <linux/clk.h> 30 31 32 struct fixed_voltage_data { 33 struct regulator_desc desc; 34 struct regulator_dev *dev; 35 36 struct clk *enable_clock; 37 unsigned int clk_enable_counter; 38 }; 39 40 struct fixed_dev_type { 41 bool has_enable_clock; 42 }; 43 44 static const struct fixed_dev_type fixed_voltage_data = { 45 .has_enable_clock = false, 46 }; 47 48 static const struct fixed_dev_type fixed_clkenable_data = { 49 .has_enable_clock = true, 50 }; 51 52 static int reg_clock_enable(struct regulator_dev *rdev) 53 { 54 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev); 55 int ret = 0; 56 57 ret = clk_prepare_enable(priv->enable_clock); 58 if (ret) 59 return ret; 60 61 priv->clk_enable_counter++; 62 63 return ret; 64 } 65 66 static int reg_clock_disable(struct regulator_dev *rdev) 67 { 68 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev); 69 70 clk_disable_unprepare(priv->enable_clock); 71 priv->clk_enable_counter--; 72 73 return 0; 74 } 75 76 static int reg_clock_is_enabled(struct regulator_dev *rdev) 77 { 78 struct fixed_voltage_data *priv = rdev_get_drvdata(rdev); 79 80 return priv->clk_enable_counter > 0; 81 } 82 83 84 /** 85 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info 86 * @dev: device requesting for fixed_voltage_config 87 * @desc: regulator description 88 * 89 * Populates fixed_voltage_config structure by extracting data from device 90 * tree node, returns a pointer to the populated structure of NULL if memory 91 * alloc fails. 92 */ 93 static struct fixed_voltage_config * 94 of_get_fixed_voltage_config(struct device *dev, 95 const struct regulator_desc *desc) 96 { 97 struct fixed_voltage_config *config; 98 struct device_node *np = dev->of_node; 99 struct regulator_init_data *init_data; 100 101 config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config), 102 GFP_KERNEL); 103 if (!config) 104 return ERR_PTR(-ENOMEM); 105 106 config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc); 107 if (!config->init_data) 108 return ERR_PTR(-EINVAL); 109 110 init_data = config->init_data; 111 init_data->constraints.apply_uV = 0; 112 113 config->supply_name = init_data->constraints.name; 114 if (init_data->constraints.min_uV == init_data->constraints.max_uV) { 115 config->microvolts = init_data->constraints.min_uV; 116 } else { 117 dev_err(dev, 118 "Fixed regulator specified with variable voltages\n"); 119 return ERR_PTR(-EINVAL); 120 } 121 122 if (init_data->constraints.boot_on) 123 config->enabled_at_boot = true; 124 125 of_property_read_u32(np, "startup-delay-us", &config->startup_delay); 126 127 if (of_find_property(np, "vin-supply", NULL)) 128 config->input_supply = "vin"; 129 130 return config; 131 } 132 133 static struct regulator_ops fixed_voltage_ops = { 134 }; 135 136 static struct regulator_ops fixed_voltage_clkenabled_ops = { 137 .enable = reg_clock_enable, 138 .disable = reg_clock_disable, 139 .is_enabled = reg_clock_is_enabled, 140 }; 141 142 static int reg_fixed_voltage_probe(struct platform_device *pdev) 143 { 144 struct device *dev = &pdev->dev; 145 struct fixed_voltage_config *config; 146 struct fixed_voltage_data *drvdata; 147 const struct fixed_dev_type *drvtype = 148 of_match_device(dev->driver->of_match_table, dev)->data; 149 struct regulator_config cfg = { }; 150 enum gpiod_flags gflags; 151 int ret; 152 153 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data), 154 GFP_KERNEL); 155 if (!drvdata) 156 return -ENOMEM; 157 158 if (pdev->dev.of_node) { 159 config = of_get_fixed_voltage_config(&pdev->dev, 160 &drvdata->desc); 161 if (IS_ERR(config)) 162 return PTR_ERR(config); 163 } else { 164 config = dev_get_platdata(&pdev->dev); 165 } 166 167 if (!config) 168 return -ENOMEM; 169 170 drvdata->desc.name = devm_kstrdup(&pdev->dev, 171 config->supply_name, 172 GFP_KERNEL); 173 if (drvdata->desc.name == NULL) { 174 dev_err(&pdev->dev, "Failed to allocate supply name\n"); 175 return -ENOMEM; 176 } 177 drvdata->desc.type = REGULATOR_VOLTAGE; 178 drvdata->desc.owner = THIS_MODULE; 179 180 if (drvtype->has_enable_clock) { 181 drvdata->desc.ops = &fixed_voltage_clkenabled_ops; 182 183 drvdata->enable_clock = devm_clk_get(dev, NULL); 184 if (IS_ERR(drvdata->enable_clock)) { 185 dev_err(dev, "Cant get enable-clock from devicetree\n"); 186 return -ENOENT; 187 } 188 } else { 189 drvdata->desc.ops = &fixed_voltage_ops; 190 } 191 192 drvdata->desc.enable_time = config->startup_delay; 193 194 if (config->input_supply) { 195 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev, 196 config->input_supply, 197 GFP_KERNEL); 198 if (!drvdata->desc.supply_name) { 199 dev_err(&pdev->dev, 200 "Failed to allocate input supply\n"); 201 return -ENOMEM; 202 } 203 } 204 205 if (config->microvolts) 206 drvdata->desc.n_voltages = 1; 207 208 drvdata->desc.fixed_uV = config->microvolts; 209 210 /* 211 * The signal will be inverted by the GPIO core if flagged so in the 212 * decriptor. 213 */ 214 if (config->enabled_at_boot) 215 gflags = GPIOD_OUT_HIGH; 216 else 217 gflags = GPIOD_OUT_LOW; 218 219 /* 220 * Some fixed regulators share the enable line between two 221 * regulators which makes it necessary to get a handle on the 222 * same descriptor for two different consumers. This will get 223 * the GPIO descriptor, but only the first call will initialize 224 * it so any flags such as inversion or open drain will only 225 * be set up by the first caller and assumed identical on the 226 * next caller. 227 * 228 * FIXME: find a better way to deal with this. 229 */ 230 gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE; 231 232 /* 233 * Do not use devm* here: the regulator core takes over the 234 * lifecycle management of the GPIO descriptor. 235 */ 236 cfg.ena_gpiod = gpiod_get_optional(&pdev->dev, NULL, gflags); 237 if (IS_ERR(cfg.ena_gpiod)) 238 return PTR_ERR(cfg.ena_gpiod); 239 240 cfg.dev = &pdev->dev; 241 cfg.init_data = config->init_data; 242 cfg.driver_data = drvdata; 243 cfg.of_node = pdev->dev.of_node; 244 245 drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc, 246 &cfg); 247 if (IS_ERR(drvdata->dev)) { 248 ret = PTR_ERR(drvdata->dev); 249 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret); 250 return ret; 251 } 252 253 platform_set_drvdata(pdev, drvdata); 254 255 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name, 256 drvdata->desc.fixed_uV); 257 258 return 0; 259 } 260 261 #if defined(CONFIG_OF) 262 static const struct of_device_id fixed_of_match[] = { 263 { 264 .compatible = "regulator-fixed", 265 .data = &fixed_voltage_data, 266 }, 267 { 268 .compatible = "regulator-fixed-clock", 269 .data = &fixed_clkenable_data, 270 }, 271 { 272 }, 273 }; 274 MODULE_DEVICE_TABLE(of, fixed_of_match); 275 #endif 276 277 static struct platform_driver regulator_fixed_voltage_driver = { 278 .probe = reg_fixed_voltage_probe, 279 .driver = { 280 .name = "reg-fixed-voltage", 281 .of_match_table = of_match_ptr(fixed_of_match), 282 }, 283 }; 284 285 static int __init regulator_fixed_voltage_init(void) 286 { 287 return platform_driver_register(®ulator_fixed_voltage_driver); 288 } 289 subsys_initcall(regulator_fixed_voltage_init); 290 291 static void __exit regulator_fixed_voltage_exit(void) 292 { 293 platform_driver_unregister(®ulator_fixed_voltage_driver); 294 } 295 module_exit(regulator_fixed_voltage_exit); 296 297 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>"); 298 MODULE_DESCRIPTION("Fixed voltage regulator"); 299 MODULE_LICENSE("GPL"); 300 MODULE_ALIAS("platform:reg-fixed-voltage"); 301