1 /* 2 * OF helpers for the GPIO API 3 * 4 * Copyright (c) 2007-2008 MontaVista Software, Inc. 5 * 6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 */ 13 14 #include <linux/device.h> 15 #include <linux/err.h> 16 #include <linux/errno.h> 17 #include <linux/module.h> 18 #include <linux/io.h> 19 #include <linux/gpio/consumer.h> 20 #include <linux/of.h> 21 #include <linux/of_address.h> 22 #include <linux/of_gpio.h> 23 #include <linux/pinctrl/pinctrl.h> 24 #include <linux/slab.h> 25 26 #include "gpiolib.h" 27 28 /* Private data structure for of_gpiochip_find_and_xlate */ 29 struct gg_data { 30 enum of_gpio_flags *flags; 31 struct of_phandle_args gpiospec; 32 33 struct gpio_desc *out_gpio; 34 }; 35 36 /* Private function for resolving node pointer to gpio_chip */ 37 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data) 38 { 39 struct gg_data *gg_data = data; 40 int ret; 41 42 if ((gc->of_node != gg_data->gpiospec.np) || 43 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) || 44 (!gc->of_xlate)) 45 return false; 46 47 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags); 48 if (ret < 0) { 49 /* We've found a gpio chip, but the translation failed. 50 * Store translation error in out_gpio. 51 * Return false to keep looking, as more than one gpio chip 52 * could be registered per of-node. 53 */ 54 gg_data->out_gpio = ERR_PTR(ret); 55 return false; 56 } 57 58 gg_data->out_gpio = gpiochip_get_desc(gc, ret); 59 return true; 60 } 61 62 /** 63 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API 64 * @np: device node to get GPIO from 65 * @propname: property name containing gpio specifier(s) 66 * @index: index of the GPIO 67 * @flags: a flags pointer to fill in 68 * 69 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 70 * value on the error condition. If @flags is not NULL the function also fills 71 * in flags for the GPIO. 72 */ 73 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, 74 const char *propname, int index, enum of_gpio_flags *flags) 75 { 76 /* Return -EPROBE_DEFER to support probe() functions to be called 77 * later when the GPIO actually becomes available 78 */ 79 struct gg_data gg_data = { 80 .flags = flags, 81 .out_gpio = ERR_PTR(-EPROBE_DEFER) 82 }; 83 int ret; 84 85 /* .of_xlate might decide to not fill in the flags, so clear it. */ 86 if (flags) 87 *flags = 0; 88 89 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, 90 &gg_data.gpiospec); 91 if (ret) { 92 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n", 93 __func__, propname, np->full_name, index); 94 return ERR_PTR(ret); 95 } 96 97 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); 98 99 of_node_put(gg_data.gpiospec.np); 100 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n", 101 __func__, propname, np->full_name, index, 102 PTR_ERR_OR_ZERO(gg_data.out_gpio)); 103 return gg_data.out_gpio; 104 } 105 106 int of_get_named_gpio_flags(struct device_node *np, const char *list_name, 107 int index, enum of_gpio_flags *flags) 108 { 109 struct gpio_desc *desc; 110 111 desc = of_get_named_gpiod_flags(np, list_name, index, flags); 112 113 if (IS_ERR(desc)) 114 return PTR_ERR(desc); 115 else 116 return desc_to_gpio(desc); 117 } 118 EXPORT_SYMBOL(of_get_named_gpio_flags); 119 120 /** 121 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags 122 * @gc: pointer to the gpio_chip structure 123 * @np: device node of the GPIO chip 124 * @gpio_spec: gpio specifier as found in the device tree 125 * @flags: a flags pointer to fill in 126 * 127 * This is simple translation function, suitable for the most 1:1 mapped 128 * gpio chips. This function performs only one sanity check: whether gpio 129 * is less than ngpios (that is specified in the gpio_chip). 130 */ 131 int of_gpio_simple_xlate(struct gpio_chip *gc, 132 const struct of_phandle_args *gpiospec, u32 *flags) 133 { 134 /* 135 * We're discouraging gpio_cells < 2, since that way you'll have to 136 * write your own xlate function (that will have to retrive the GPIO 137 * number and the flags from a single gpio cell -- this is possible, 138 * but not recommended). 139 */ 140 if (gc->of_gpio_n_cells < 2) { 141 WARN_ON(1); 142 return -EINVAL; 143 } 144 145 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 146 return -EINVAL; 147 148 if (gpiospec->args[0] >= gc->ngpio) 149 return -EINVAL; 150 151 if (flags) 152 *flags = gpiospec->args[1]; 153 154 return gpiospec->args[0]; 155 } 156 EXPORT_SYMBOL(of_gpio_simple_xlate); 157 158 /** 159 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) 160 * @np: device node of the GPIO chip 161 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 162 * 163 * To use this function you should allocate and fill mm_gc with: 164 * 165 * 1) In the gpio_chip structure: 166 * - all the callbacks 167 * - of_gpio_n_cells 168 * - of_xlate callback (optional) 169 * 170 * 3) In the of_mm_gpio_chip structure: 171 * - save_regs callback (optional) 172 * 173 * If succeeded, this function will map bank's memory and will 174 * do all necessary work for you. Then you'll able to use .regs 175 * to manage GPIOs from the callbacks. 176 */ 177 int of_mm_gpiochip_add(struct device_node *np, 178 struct of_mm_gpio_chip *mm_gc) 179 { 180 int ret = -ENOMEM; 181 struct gpio_chip *gc = &mm_gc->gc; 182 183 gc->label = kstrdup(np->full_name, GFP_KERNEL); 184 if (!gc->label) 185 goto err0; 186 187 mm_gc->regs = of_iomap(np, 0); 188 if (!mm_gc->regs) 189 goto err1; 190 191 gc->base = -1; 192 193 if (mm_gc->save_regs) 194 mm_gc->save_regs(mm_gc); 195 196 mm_gc->gc.of_node = np; 197 198 ret = gpiochip_add(gc); 199 if (ret) 200 goto err2; 201 202 return 0; 203 err2: 204 iounmap(mm_gc->regs); 205 err1: 206 kfree(gc->label); 207 err0: 208 pr_err("%s: GPIO chip registration failed with status %d\n", 209 np->full_name, ret); 210 return ret; 211 } 212 EXPORT_SYMBOL(of_mm_gpiochip_add); 213 214 /** 215 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank) 216 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 217 */ 218 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc) 219 { 220 struct gpio_chip *gc = &mm_gc->gc; 221 222 if (!mm_gc) 223 return; 224 225 gpiochip_remove(gc); 226 iounmap(mm_gc->regs); 227 kfree(gc->label); 228 } 229 EXPORT_SYMBOL(of_mm_gpiochip_remove); 230 231 #ifdef CONFIG_PINCTRL 232 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) 233 { 234 struct device_node *np = chip->of_node; 235 struct of_phandle_args pinspec; 236 struct pinctrl_dev *pctldev; 237 int index = 0, ret; 238 const char *name; 239 static const char group_names_propname[] = "gpio-ranges-group-names"; 240 struct property *group_names; 241 242 if (!np) 243 return; 244 245 group_names = of_find_property(np, group_names_propname, NULL); 246 247 for (;; index++) { 248 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 249 index, &pinspec); 250 if (ret) 251 break; 252 253 pctldev = of_pinctrl_get(pinspec.np); 254 if (!pctldev) 255 break; 256 257 if (pinspec.args[2]) { 258 if (group_names) { 259 ret = of_property_read_string_index(np, 260 group_names_propname, 261 index, &name); 262 if (strlen(name)) { 263 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n", 264 np->full_name); 265 break; 266 } 267 } 268 /* npins != 0: linear range */ 269 ret = gpiochip_add_pin_range(chip, 270 pinctrl_dev_get_devname(pctldev), 271 pinspec.args[0], 272 pinspec.args[1], 273 pinspec.args[2]); 274 if (ret) 275 break; 276 } else { 277 /* npins == 0: special range */ 278 if (pinspec.args[1]) { 279 pr_err("%s: Illegal gpio-range format.\n", 280 np->full_name); 281 break; 282 } 283 284 if (!group_names) { 285 pr_err("%s: GPIO group range requested but no %s property.\n", 286 np->full_name, group_names_propname); 287 break; 288 } 289 290 ret = of_property_read_string_index(np, 291 group_names_propname, 292 index, &name); 293 if (ret) 294 break; 295 296 if (!strlen(name)) { 297 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n", 298 np->full_name); 299 break; 300 } 301 302 ret = gpiochip_add_pingroup_range(chip, pctldev, 303 pinspec.args[0], name); 304 if (ret) 305 break; 306 } 307 } 308 } 309 310 #else 311 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {} 312 #endif 313 314 void of_gpiochip_add(struct gpio_chip *chip) 315 { 316 if ((!chip->of_node) && (chip->dev)) 317 chip->of_node = chip->dev->of_node; 318 319 if (!chip->of_node) 320 return; 321 322 if (!chip->of_xlate) { 323 chip->of_gpio_n_cells = 2; 324 chip->of_xlate = of_gpio_simple_xlate; 325 } 326 327 of_gpiochip_add_pin_range(chip); 328 of_node_get(chip->of_node); 329 } 330 331 void of_gpiochip_remove(struct gpio_chip *chip) 332 { 333 gpiochip_remove_pin_ranges(chip); 334 of_node_put(chip->of_node); 335 } 336