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 #include <linux/gpio/machine.h> 26 27 #include "gpiolib.h" 28 29 /* Private data structure for of_gpiochip_find_and_xlate */ 30 struct gg_data { 31 enum of_gpio_flags *flags; 32 struct of_phandle_args gpiospec; 33 34 struct gpio_desc *out_gpio; 35 }; 36 37 /* Private function for resolving node pointer to gpio_chip */ 38 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data) 39 { 40 struct gg_data *gg_data = data; 41 int ret; 42 43 if ((gc->of_node != gg_data->gpiospec.np) || 44 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) || 45 (!gc->of_xlate)) 46 return false; 47 48 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags); 49 if (ret < 0) { 50 /* We've found a gpio chip, but the translation failed. 51 * Store translation error in out_gpio. 52 * Return false to keep looking, as more than one gpio chip 53 * could be registered per of-node. 54 */ 55 gg_data->out_gpio = ERR_PTR(ret); 56 return false; 57 } 58 59 gg_data->out_gpio = gpiochip_get_desc(gc, ret); 60 return true; 61 } 62 63 /** 64 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API 65 * @np: device node to get GPIO from 66 * @propname: property name containing gpio specifier(s) 67 * @index: index of the GPIO 68 * @flags: a flags pointer to fill in 69 * 70 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 71 * value on the error condition. If @flags is not NULL the function also fills 72 * in flags for the GPIO. 73 */ 74 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, 75 const char *propname, int index, enum of_gpio_flags *flags) 76 { 77 /* Return -EPROBE_DEFER to support probe() functions to be called 78 * later when the GPIO actually becomes available 79 */ 80 struct gg_data gg_data = { 81 .flags = flags, 82 .out_gpio = ERR_PTR(-EPROBE_DEFER) 83 }; 84 int ret; 85 86 /* .of_xlate might decide to not fill in the flags, so clear it. */ 87 if (flags) 88 *flags = 0; 89 90 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, 91 &gg_data.gpiospec); 92 if (ret) { 93 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n", 94 __func__, propname, np->full_name, index); 95 return ERR_PTR(ret); 96 } 97 98 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); 99 100 of_node_put(gg_data.gpiospec.np); 101 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n", 102 __func__, propname, np->full_name, index, 103 PTR_ERR_OR_ZERO(gg_data.out_gpio)); 104 return gg_data.out_gpio; 105 } 106 107 int of_get_named_gpio_flags(struct device_node *np, const char *list_name, 108 int index, enum of_gpio_flags *flags) 109 { 110 struct gpio_desc *desc; 111 112 desc = of_get_named_gpiod_flags(np, list_name, index, flags); 113 114 if (IS_ERR(desc)) 115 return PTR_ERR(desc); 116 else 117 return desc_to_gpio(desc); 118 } 119 EXPORT_SYMBOL(of_get_named_gpio_flags); 120 121 /** 122 * of_get_gpio_hog() - Get a GPIO hog descriptor, names and flags for GPIO API 123 * @np: device node to get GPIO from 124 * @name: GPIO line name 125 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or 126 * of_get_gpio_hog() 127 * @dflags: gpiod_flags - optional GPIO initialization flags 128 * 129 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 130 * value on the error condition. 131 */ 132 static struct gpio_desc *of_get_gpio_hog(struct device_node *np, 133 const char **name, 134 enum gpio_lookup_flags *lflags, 135 enum gpiod_flags *dflags) 136 { 137 struct device_node *chip_np; 138 enum of_gpio_flags xlate_flags; 139 struct gpio_desc *desc; 140 struct gg_data gg_data = { 141 .flags = &xlate_flags, 142 }; 143 u32 tmp; 144 int i, ret; 145 146 chip_np = np->parent; 147 if (!chip_np) 148 return ERR_PTR(-EINVAL); 149 150 xlate_flags = 0; 151 *lflags = 0; 152 *dflags = 0; 153 154 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp); 155 if (ret) 156 return ERR_PTR(ret); 157 158 if (tmp > MAX_PHANDLE_ARGS) 159 return ERR_PTR(-EINVAL); 160 161 gg_data.gpiospec.args_count = tmp; 162 gg_data.gpiospec.np = chip_np; 163 for (i = 0; i < tmp; i++) { 164 ret = of_property_read_u32_index(np, "gpios", i, 165 &gg_data.gpiospec.args[i]); 166 if (ret) 167 return ERR_PTR(ret); 168 } 169 170 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); 171 if (!gg_data.out_gpio) { 172 if (np->parent == np) 173 return ERR_PTR(-ENXIO); 174 else 175 return ERR_PTR(-EINVAL); 176 } 177 178 if (xlate_flags & OF_GPIO_ACTIVE_LOW) 179 *lflags |= GPIO_ACTIVE_LOW; 180 181 if (of_property_read_bool(np, "input")) 182 *dflags |= GPIOD_IN; 183 else if (of_property_read_bool(np, "output-low")) 184 *dflags |= GPIOD_OUT_LOW; 185 else if (of_property_read_bool(np, "output-high")) 186 *dflags |= GPIOD_OUT_HIGH; 187 else { 188 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n", 189 desc_to_gpio(gg_data.out_gpio), np->name); 190 return ERR_PTR(-EINVAL); 191 } 192 193 if (name && of_property_read_string(np, "line-name", name)) 194 *name = np->name; 195 196 desc = gg_data.out_gpio; 197 198 return desc; 199 } 200 201 /** 202 * of_gpiochip_scan_hogs - Scan gpio-controller and apply GPIO hog as requested 203 * @chip: gpio chip to act on 204 * 205 * This is only used by of_gpiochip_add to request/set GPIO initial 206 * configuration. 207 */ 208 static void of_gpiochip_scan_hogs(struct gpio_chip *chip) 209 { 210 struct gpio_desc *desc = NULL; 211 struct device_node *np; 212 const char *name; 213 enum gpio_lookup_flags lflags; 214 enum gpiod_flags dflags; 215 216 for_each_child_of_node(chip->of_node, np) { 217 if (!of_property_read_bool(np, "gpio-hog")) 218 continue; 219 220 desc = of_get_gpio_hog(np, &name, &lflags, &dflags); 221 if (IS_ERR(desc)) 222 continue; 223 224 if (gpiod_hog(desc, name, lflags, dflags)) 225 continue; 226 } 227 } 228 229 /** 230 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags 231 * @gc: pointer to the gpio_chip structure 232 * @np: device node of the GPIO chip 233 * @gpio_spec: gpio specifier as found in the device tree 234 * @flags: a flags pointer to fill in 235 * 236 * This is simple translation function, suitable for the most 1:1 mapped 237 * gpio chips. This function performs only one sanity check: whether gpio 238 * is less than ngpios (that is specified in the gpio_chip). 239 */ 240 int of_gpio_simple_xlate(struct gpio_chip *gc, 241 const struct of_phandle_args *gpiospec, u32 *flags) 242 { 243 /* 244 * We're discouraging gpio_cells < 2, since that way you'll have to 245 * write your own xlate function (that will have to retrieve the GPIO 246 * number and the flags from a single gpio cell -- this is possible, 247 * but not recommended). 248 */ 249 if (gc->of_gpio_n_cells < 2) { 250 WARN_ON(1); 251 return -EINVAL; 252 } 253 254 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 255 return -EINVAL; 256 257 if (gpiospec->args[0] >= gc->ngpio) 258 return -EINVAL; 259 260 if (flags) 261 *flags = gpiospec->args[1]; 262 263 return gpiospec->args[0]; 264 } 265 EXPORT_SYMBOL(of_gpio_simple_xlate); 266 267 /** 268 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) 269 * @np: device node of the GPIO chip 270 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 271 * 272 * To use this function you should allocate and fill mm_gc with: 273 * 274 * 1) In the gpio_chip structure: 275 * - all the callbacks 276 * - of_gpio_n_cells 277 * - of_xlate callback (optional) 278 * 279 * 3) In the of_mm_gpio_chip structure: 280 * - save_regs callback (optional) 281 * 282 * If succeeded, this function will map bank's memory and will 283 * do all necessary work for you. Then you'll able to use .regs 284 * to manage GPIOs from the callbacks. 285 */ 286 int of_mm_gpiochip_add(struct device_node *np, 287 struct of_mm_gpio_chip *mm_gc) 288 { 289 int ret = -ENOMEM; 290 struct gpio_chip *gc = &mm_gc->gc; 291 292 gc->label = kstrdup(np->full_name, GFP_KERNEL); 293 if (!gc->label) 294 goto err0; 295 296 mm_gc->regs = of_iomap(np, 0); 297 if (!mm_gc->regs) 298 goto err1; 299 300 gc->base = -1; 301 302 if (mm_gc->save_regs) 303 mm_gc->save_regs(mm_gc); 304 305 mm_gc->gc.of_node = np; 306 307 ret = gpiochip_add(gc); 308 if (ret) 309 goto err2; 310 311 return 0; 312 err2: 313 iounmap(mm_gc->regs); 314 err1: 315 kfree(gc->label); 316 err0: 317 pr_err("%s: GPIO chip registration failed with status %d\n", 318 np->full_name, ret); 319 return ret; 320 } 321 EXPORT_SYMBOL(of_mm_gpiochip_add); 322 323 /** 324 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank) 325 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 326 */ 327 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc) 328 { 329 struct gpio_chip *gc = &mm_gc->gc; 330 331 if (!mm_gc) 332 return; 333 334 gpiochip_remove(gc); 335 iounmap(mm_gc->regs); 336 kfree(gc->label); 337 } 338 EXPORT_SYMBOL(of_mm_gpiochip_remove); 339 340 #ifdef CONFIG_PINCTRL 341 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) 342 { 343 struct device_node *np = chip->of_node; 344 struct of_phandle_args pinspec; 345 struct pinctrl_dev *pctldev; 346 int index = 0, ret; 347 const char *name; 348 static const char group_names_propname[] = "gpio-ranges-group-names"; 349 struct property *group_names; 350 351 if (!np) 352 return; 353 354 group_names = of_find_property(np, group_names_propname, NULL); 355 356 for (;; index++) { 357 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 358 index, &pinspec); 359 if (ret) 360 break; 361 362 pctldev = of_pinctrl_get(pinspec.np); 363 if (!pctldev) 364 break; 365 366 if (pinspec.args[2]) { 367 if (group_names) { 368 ret = of_property_read_string_index(np, 369 group_names_propname, 370 index, &name); 371 if (strlen(name)) { 372 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n", 373 np->full_name); 374 break; 375 } 376 } 377 /* npins != 0: linear range */ 378 ret = gpiochip_add_pin_range(chip, 379 pinctrl_dev_get_devname(pctldev), 380 pinspec.args[0], 381 pinspec.args[1], 382 pinspec.args[2]); 383 if (ret) 384 break; 385 } else { 386 /* npins == 0: special range */ 387 if (pinspec.args[1]) { 388 pr_err("%s: Illegal gpio-range format.\n", 389 np->full_name); 390 break; 391 } 392 393 if (!group_names) { 394 pr_err("%s: GPIO group range requested but no %s property.\n", 395 np->full_name, group_names_propname); 396 break; 397 } 398 399 ret = of_property_read_string_index(np, 400 group_names_propname, 401 index, &name); 402 if (ret) 403 break; 404 405 if (!strlen(name)) { 406 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n", 407 np->full_name); 408 break; 409 } 410 411 ret = gpiochip_add_pingroup_range(chip, pctldev, 412 pinspec.args[0], name); 413 if (ret) 414 break; 415 } 416 } 417 } 418 419 #else 420 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {} 421 #endif 422 423 void of_gpiochip_add(struct gpio_chip *chip) 424 { 425 if ((!chip->of_node) && (chip->dev)) 426 chip->of_node = chip->dev->of_node; 427 428 if (!chip->of_node) 429 return; 430 431 if (!chip->of_xlate) { 432 chip->of_gpio_n_cells = 2; 433 chip->of_xlate = of_gpio_simple_xlate; 434 } 435 436 of_gpiochip_add_pin_range(chip); 437 of_node_get(chip->of_node); 438 439 of_gpiochip_scan_hogs(chip); 440 } 441 442 void of_gpiochip_remove(struct gpio_chip *chip) 443 { 444 gpiochip_remove_pin_ranges(chip); 445 of_node_put(chip->of_node); 446 } 447