1 /* 2 * Copyright (c) 2011 The Chromium OS Authors. 3 * Copyright (c) 2011, NVIDIA Corp. All rights reserved. 4 * SPDX-License-Identifier: GPL-2.0+ 5 */ 6 7 #ifndef _ASM_GENERIC_GPIO_H_ 8 #define _ASM_GENERIC_GPIO_H_ 9 10 struct ofnode_phandle_args; 11 12 /* 13 * Generic GPIO API for U-Boot 14 * 15 * -- 16 * NB: This is deprecated. Please use the driver model functions instead: 17 * 18 * - gpio_request_by_name() 19 * - dm_gpio_get_value() etc. 20 * 21 * For now we need a dm_ prefix on some functions to avoid name collision. 22 * -- 23 * 24 * GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined 25 * by the SOC/architecture. 26 * 27 * Each GPIO can be an input or output. If an input then its value can 28 * be read as 0 or 1. If an output then its value can be set to 0 or 1. 29 * If you try to write an input then the value is undefined. If you try 30 * to read an output, barring something very unusual, you will get 31 * back the value of the output that you previously set. 32 * 33 * In some cases the operation may fail, for example if the GPIO number 34 * is out of range, or the GPIO is not available because its pin is 35 * being used by another function. In that case, functions may return 36 * an error value of -1. 37 */ 38 39 /** 40 * @deprecated Please use driver model instead 41 * Request a GPIO. This should be called before any of the other functions 42 * are used on this GPIO. 43 * 44 * Note: With driver model, the label is allocated so there is no need for 45 * the caller to preserve it. 46 * 47 * @param gpio GPIO number 48 * @param label User label for this GPIO 49 * @return 0 if ok, -1 on error 50 */ 51 int gpio_request(unsigned gpio, const char *label); 52 53 /** 54 * @deprecated Please use driver model instead 55 * Stop using the GPIO. This function should not alter pin configuration. 56 * 57 * @param gpio GPIO number 58 * @return 0 if ok, -1 on error 59 */ 60 int gpio_free(unsigned gpio); 61 62 /** 63 * @deprecated Please use driver model instead 64 * Make a GPIO an input. 65 * 66 * @param gpio GPIO number 67 * @return 0 if ok, -1 on error 68 */ 69 int gpio_direction_input(unsigned gpio); 70 71 /** 72 * @deprecated Please use driver model instead 73 * Make a GPIO an output, and set its value. 74 * 75 * @param gpio GPIO number 76 * @param value GPIO value (0 for low or 1 for high) 77 * @return 0 if ok, -1 on error 78 */ 79 int gpio_direction_output(unsigned gpio, int value); 80 81 /** 82 * @deprecated Please use driver model instead 83 * Get a GPIO's value. This will work whether the GPIO is an input 84 * or an output. 85 * 86 * @param gpio GPIO number 87 * @return 0 if low, 1 if high, -1 on error 88 */ 89 int gpio_get_value(unsigned gpio); 90 91 /** 92 * @deprecated Please use driver model instead 93 * Set an output GPIO's value. The GPIO must already be an output or 94 * this function may have no effect. 95 * 96 * @param gpio GPIO number 97 * @param value GPIO value (0 for low or 1 for high) 98 * @return 0 if ok, -1 on error 99 */ 100 int gpio_set_value(unsigned gpio, int value); 101 102 /* State of a GPIO, as reported by get_function() */ 103 enum gpio_func_t { 104 GPIOF_INPUT = 0, 105 GPIOF_OUTPUT, 106 GPIOF_UNUSED, /* Not claimed */ 107 GPIOF_UNKNOWN, /* Not known */ 108 GPIOF_FUNC, /* Not used as a GPIO */ 109 110 GPIOF_COUNT, 111 }; 112 113 struct udevice; 114 115 struct gpio_desc { 116 struct udevice *dev; /* Device, NULL for invalid GPIO */ 117 unsigned long flags; 118 #define GPIOD_REQUESTED (1 << 0) /* Requested/claimed */ 119 #define GPIOD_IS_OUT (1 << 1) /* GPIO is an output */ 120 #define GPIOD_IS_IN (1 << 2) /* GPIO is an input */ 121 #define GPIOD_ACTIVE_LOW (1 << 3) /* value has active low */ 122 #define GPIOD_IS_OUT_ACTIVE (1 << 4) /* set output active */ 123 124 uint offset; /* GPIO offset within the device */ 125 /* 126 * We could consider adding the GPIO label in here. Possibly we could 127 * use this structure for internal GPIO information. 128 */ 129 }; 130 131 /** 132 * dm_gpio_is_valid() - Check if a GPIO is valid 133 * 134 * @desc: GPIO description containing device, offset and flags, 135 * previously returned by gpio_request_by_name() 136 * @return true if valid, false if not 137 */ 138 static inline bool dm_gpio_is_valid(const struct gpio_desc *desc) 139 { 140 return desc->dev != NULL; 141 } 142 143 /** 144 * gpio_get_status() - get the current GPIO status as a string 145 * 146 * Obtain the current GPIO status as a string which can be presented to the 147 * user. A typical string is: 148 * 149 * "b4: in: 1 [x] sdmmc_cd" 150 * 151 * which means this is GPIO bank b, offset 4, currently set to input, current 152 * value 1, [x] means that it is requested and the owner is 'sdmmc_cd' 153 * 154 * TODO(sjg@chromium.org): This should use struct gpio_desc 155 * 156 * @dev: Device to check 157 * @offset: Offset of device GPIO to check 158 * @buf: Place to put string 159 * @buffsize: Size of string including \0 160 */ 161 int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize); 162 163 /** 164 * gpio_get_function() - get the current function for a GPIO pin 165 * 166 * Note this returns GPIOF_UNUSED if the GPIO is not requested. 167 * 168 * TODO(sjg@chromium.org): This should use struct gpio_desc 169 * 170 * @dev: Device to check 171 * @offset: Offset of device GPIO to check 172 * @namep: If non-NULL, this is set to the name given when the GPIO 173 * was requested, or -1 if it has not been requested 174 * @return -ENODATA if the driver returned an unknown function, 175 * -ENODEV if the device is not active, -EINVAL if the offset is invalid. 176 * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the 177 * function from enum gpio_func_t. 178 */ 179 int gpio_get_function(struct udevice *dev, int offset, const char **namep); 180 181 /** 182 * gpio_get_raw_function() - get the current raw function for a GPIO pin 183 * 184 * Note this does not return GPIOF_UNUSED - it will always return the GPIO 185 * driver's view of a pin function, even if it is not correctly set up. 186 * 187 * TODO(sjg@chromium.org): This should use struct gpio_desc 188 * 189 * @dev: Device to check 190 * @offset: Offset of device GPIO to check 191 * @namep: If non-NULL, this is set to the name given when the GPIO 192 * was requested, or -1 if it has not been requested 193 * @return -ENODATA if the driver returned an unknown function, 194 * -ENODEV if the device is not active, -EINVAL if the offset is invalid. 195 * Otherwise returns the function from enum gpio_func_t. 196 */ 197 int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep); 198 199 /** 200 * gpio_requestf() - request a GPIO using a format string for the owner 201 * 202 * This is a helper function for gpio_request(). It allows you to provide 203 * a printf()-format string for the GPIO owner. It calls gpio_request() with 204 * the string that is created 205 */ 206 int gpio_requestf(unsigned gpio, const char *fmt, ...) 207 __attribute__ ((format (__printf__, 2, 3))); 208 209 struct fdtdec_phandle_args; 210 211 /** 212 * gpio_xlate_offs_flags() - implementation for common use of dm_gpio_ops.xlate 213 * 214 * This routine sets the offset field to args[0] and the flags field to 215 * GPIOD_ACTIVE_LOW if the GPIO_ACTIVE_LOW flag is present in args[1]. 216 */ 217 int gpio_xlate_offs_flags(struct udevice *dev, struct gpio_desc *desc, 218 struct ofnode_phandle_args *args); 219 220 /** 221 * struct struct dm_gpio_ops - Driver model GPIO operations 222 * 223 * Refer to functions above for description. These function largely copy 224 * the old API. 225 * 226 * This is trying to be close to Linux GPIO API. Once the U-Boot uses the 227 * new DM GPIO API, this should be really easy to flip over to the Linux 228 * GPIO API-alike interface. 229 * 230 * Also it would be useful to standardise additional functions like 231 * pullup, slew rate and drive strength. 232 * 233 * gpio_request() and gpio_free() are optional - if NULL then they will 234 * not be called. 235 * 236 * Note that @offset is the offset from the base GPIO of the device. So 237 * offset 0 is the device's first GPIO and offset o-1 is the last GPIO, 238 * where o is the number of GPIO lines controlled by the device. A device 239 * is typically used to control a single bank of GPIOs. Within complex 240 * SoCs there may be many banks and therefore many devices all referring 241 * to the different IO addresses within the SoC. 242 * 243 * The uclass combines all GPIO devices together to provide a consistent 244 * numbering from 0 to n-1, where n is the number of GPIOs in total across 245 * all devices. Be careful not to confuse offset with gpio in the parameters. 246 */ 247 struct dm_gpio_ops { 248 int (*request)(struct udevice *dev, unsigned offset, const char *label); 249 int (*free)(struct udevice *dev, unsigned offset); 250 int (*direction_input)(struct udevice *dev, unsigned offset); 251 int (*direction_output)(struct udevice *dev, unsigned offset, 252 int value); 253 int (*get_value)(struct udevice *dev, unsigned offset); 254 int (*set_value)(struct udevice *dev, unsigned offset, int value); 255 int (*get_open_drain)(struct udevice *dev, unsigned offset); 256 int (*set_open_drain)(struct udevice *dev, unsigned offset, int value); 257 /** 258 * get_function() Get the GPIO function 259 * 260 * @dev: Device to check 261 * @offset: GPIO offset within that device 262 * @return current function - GPIOF_... 263 */ 264 int (*get_function)(struct udevice *dev, unsigned offset); 265 266 /** 267 * xlate() - Translate phandle arguments into a GPIO description 268 * 269 * This function should set up the fields in desc according to the 270 * information in the arguments. The uclass will have set up: 271 * 272 * @desc->dev to @dev 273 * @desc->flags to 0 274 * @desc->offset to 0 275 * 276 * This method is optional and defaults to gpio_xlate_offs_flags, 277 * which will parse offset and the GPIO_ACTIVE_LOW flag in the first 278 * two arguments. 279 * 280 * Note that @dev is passed in as a parameter to follow driver model 281 * uclass conventions, even though it is already available as 282 * desc->dev. 283 * 284 * @dev: GPIO device 285 * @desc: Place to put GPIO description 286 * @args: Arguments provided in description 287 * @return 0 if OK, -ve on error 288 */ 289 int (*xlate)(struct udevice *dev, struct gpio_desc *desc, 290 struct ofnode_phandle_args *args); 291 }; 292 293 /** 294 * struct gpio_dev_priv - information about a device used by the uclass 295 * 296 * The uclass combines all active GPIO devices into a unified numbering 297 * scheme. To do this it maintains some private information about each 298 * device. 299 * 300 * To implement driver model support in your GPIO driver, add a probe 301 * handler, and set @gpio_count and @bank_name correctly in that handler. 302 * This tells the uclass the name of the GPIO bank and the number of GPIOs 303 * it contains. 304 * 305 * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called 306 * 'A0', 'A1', etc. 307 * @gpio_count: Number of GPIOs in this device 308 * @gpio_base: Base GPIO number for this device. For the first active device 309 * this will be 0; the numbering for others will follow sequentially so that 310 * @gpio_base for device 1 will equal the number of GPIOs in device 0. 311 * @name: Array of pointers to the name for each GPIO in this bank. The 312 * value of the pointer will be NULL if the GPIO has not been claimed. 313 */ 314 struct gpio_dev_priv { 315 const char *bank_name; 316 unsigned gpio_count; 317 unsigned gpio_base; 318 char **name; 319 }; 320 321 /* Access the GPIO operations for a device */ 322 #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops) 323 324 /** 325 * gpio_get_bank_info - Return information about a GPIO bank/device 326 * 327 * This looks up a device and returns both its GPIO base name and the number 328 * of GPIOs it controls. 329 * 330 * @dev: Device to look up 331 * @offset_count: Returns number of GPIOs within this bank 332 * @return bank name of this device 333 */ 334 const char *gpio_get_bank_info(struct udevice *dev, int *offset_count); 335 336 /** 337 * dm_gpio_lookup_name() - Look up a named GPIO and return its description 338 * 339 * The name of a GPIO is typically its bank name followed by a number from 0. 340 * For example A0 is the first GPIO in bank A. Each bank is a separate driver 341 * model device. 342 * 343 * @name: Name to look up 344 * @desc: Returns description, on success 345 * @return 0 if OK, -ve on error 346 */ 347 int dm_gpio_lookup_name(const char *name, struct gpio_desc *desc); 348 349 /** 350 * gpio_lookup_name - Look up a GPIO name and return its details 351 * 352 * This is used to convert a named GPIO into a device, offset and GPIO 353 * number. 354 * 355 * @name: GPIO name to look up 356 * @devp: Returns pointer to device which contains this GPIO 357 * @offsetp: Returns the offset number within this device 358 * @gpiop: Returns the absolute GPIO number, numbered from 0 359 */ 360 int gpio_lookup_name(const char *name, struct udevice **devp, 361 unsigned int *offsetp, unsigned int *gpiop); 362 363 /** 364 * gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int 365 * 366 * This puts the value of the first GPIO into bit 0, the second into bit 1, 367 * etc. then returns the resulting integer. 368 * 369 * @gpio_list: List of GPIOs to collect 370 * @return resulting integer value, or -ve on error 371 */ 372 int gpio_get_values_as_int(const int *gpio_list); 373 374 /** 375 * dm_gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int 376 * 377 * This puts the value of the first GPIO into bit 0, the second into bit 1, 378 * etc. then returns the resulting integer. 379 * 380 * @desc_list: List of GPIOs to collect 381 * @count: Number of GPIOs 382 * @return resulting integer value, or -ve on error 383 */ 384 int dm_gpio_get_values_as_int(const struct gpio_desc *desc_list, int count); 385 386 /** 387 * gpio_claim_vector() - claim a number of GPIOs for input 388 * 389 * @gpio_num_array: array of gpios to claim, terminated by -1 390 * @fmt: format string for GPIO names, e.g. "board_id%d" 391 * @return 0 if OK, -ve on error 392 */ 393 int gpio_claim_vector(const int *gpio_num_array, const char *fmt); 394 395 /** 396 * gpio_request_by_name() - Locate and request a GPIO by name 397 * 398 * This operates by looking up the given list name in the device (device 399 * tree property) and requesting the GPIO for use. The property must exist 400 * in @dev's node. 401 * 402 * Use @flags to specify whether the GPIO should be an input or output. In 403 * principle this can also come from the device tree binding but most 404 * bindings don't provide this information. Specifically, when the GPIO uclass 405 * calls the xlate() method, it can return default flags, which are then 406 * ORed with this @flags. 407 * 408 * If we find that requesting the GPIO is not always needed we could add a 409 * new function or a new GPIOD_NO_REQUEST flag. 410 * 411 * At present driver model has no reference counting so if one device 412 * requests a GPIO which subsequently is unbound, the @desc->dev pointer 413 * will be invalid. However this will only happen if the GPIO device is 414 * unbound, not if it is removed, so this seems like a reasonable limitation 415 * for now. There is no real use case for unbinding drivers in normal 416 * operation. 417 * 418 * The device tree binding is doc/device-tree-bindings/gpio/gpio.txt in 419 * generate terms and each specific device may add additional details in 420 * a binding file in the same directory. 421 * 422 * @dev: Device requesting the GPIO 423 * @list_name: Name of GPIO list (e.g. "board-id-gpios") 424 * @index: Index number of the GPIO in that list use request (0=first) 425 * @desc: Returns GPIO description information. If there is no such 426 * GPIO, dev->dev will be NULL. 427 * @flags: Indicates the GPIO input/output settings (GPIOD_...) 428 * @return 0 if OK, -ENOENT if the GPIO does not exist, -EINVAL if there is 429 * something wrong with the list, or other -ve for another error (e.g. 430 * -EBUSY if a GPIO was already requested) 431 */ 432 int gpio_request_by_name(struct udevice *dev, const char *list_name, 433 int index, struct gpio_desc *desc, int flags); 434 435 /** 436 * gpio_request_list_by_name() - Request a list of GPIOs 437 * 438 * Reads all the GPIOs from a list and requests them. See 439 * gpio_request_by_name() for additional details. Lists should not be 440 * misused to hold unrelated or optional GPIOs. They should only be used 441 * for things like parallel data lines. A zero phandle terminates the list 442 * the list. 443 * 444 * This function will either succeed, and request all GPIOs in the list, or 445 * fail and request none (it will free already-requested GPIOs in case of 446 * an error part-way through). 447 * 448 * @dev: Device requesting the GPIO 449 * @list_name: Name of GPIO list (e.g. "board-id-gpios") 450 * @desc_list: Returns a list of GPIO description information 451 * @max_count: Maximum number of GPIOs to return (@desc_list must be at least 452 * this big) 453 * @flags: Indicates the GPIO input/output settings (GPIOD_...) 454 * @return number of GPIOs requested, or -ve on error 455 */ 456 int gpio_request_list_by_name(struct udevice *dev, const char *list_name, 457 struct gpio_desc *desc_list, int max_count, 458 int flags); 459 460 /** 461 * dm_gpio_request() - manually request a GPIO 462 * 463 * Note: This function should only be used for testing / debugging. Instead. 464 * use gpio_request_by_name() to pull GPIOs from the device tree. 465 * 466 * @desc: GPIO description of GPIO to request (see dm_gpio_lookup_name()) 467 * @label: Label to attach to the GPIO while claimed 468 * @return 0 if OK, -ve on error 469 */ 470 int dm_gpio_request(struct gpio_desc *desc, const char *label); 471 472 /** 473 * gpio_get_list_count() - Returns the number of GPIOs in a list 474 * 475 * Counts the GPIOs in a list. See gpio_request_by_name() for additional 476 * details. 477 * 478 * @dev: Device requesting the GPIO 479 * @list_name: Name of GPIO list (e.g. "board-id-gpios") 480 * @return number of GPIOs (0 for an empty property) or -ENOENT if the list 481 * does not exist 482 */ 483 int gpio_get_list_count(struct udevice *dev, const char *list_name); 484 485 /** 486 * gpio_request_by_name_nodev() - request GPIOs without a device 487 * 488 * This is a version of gpio_request_list_by_name() that does not use a 489 * device. Avoid it unless the caller is not yet using driver model 490 */ 491 int gpio_request_by_name_nodev(const void *blob, int node, 492 const char *list_name, 493 int index, struct gpio_desc *desc, int flags); 494 495 /** 496 * gpio_request_list_by_name_nodev() - request GPIOs without a device 497 * 498 * This is a version of gpio_request_list_by_name() that does not use a 499 * device. Avoid it unless the caller is not yet using driver model 500 */ 501 int gpio_request_list_by_name_nodev(const void *blob, int node, 502 const char *list_name, 503 struct gpio_desc *desc_list, int max_count, 504 int flags); 505 506 /** 507 * dm_gpio_free() - Free a single GPIO 508 * 509 * This frees a single GPIOs previously returned from gpio_request_by_name(). 510 * 511 * @dev: Device which requested the GPIO 512 * @desc: GPIO to free 513 * @return 0 if OK, -ve on error 514 */ 515 int dm_gpio_free(struct udevice *dev, struct gpio_desc *desc); 516 517 /** 518 * gpio_free_list() - Free a list of GPIOs 519 * 520 * This frees a list of GPIOs previously returned from 521 * gpio_request_list_by_name(). 522 * 523 * @dev: Device which requested the GPIOs 524 * @desc: List of GPIOs to free 525 * @count: Number of GPIOs in the list 526 * @return 0 if OK, -ve on error 527 */ 528 int gpio_free_list(struct udevice *dev, struct gpio_desc *desc, int count); 529 530 /** 531 * gpio_free_list_nodev() - free GPIOs without a device 532 * 533 * This is a version of gpio_free_list() that does not use a 534 * device. Avoid it unless the caller is not yet using driver model 535 */ 536 int gpio_free_list_nodev(struct gpio_desc *desc, int count); 537 538 /** 539 * dm_gpio_get_value() - Get the value of a GPIO 540 * 541 * This is the driver model version of the existing gpio_get_value() function 542 * and should be used instead of that. 543 * 544 * For now, these functions have a dm_ prefix since they conflict with 545 * existing names. 546 * 547 * @desc: GPIO description containing device, offset and flags, 548 * previously returned by gpio_request_by_name() 549 * @return GPIO value (0 for inactive, 1 for active) or -ve on error 550 */ 551 int dm_gpio_get_value(const struct gpio_desc *desc); 552 553 int dm_gpio_set_value(const struct gpio_desc *desc, int value); 554 555 /** 556 * dm_gpio_get_open_drain() - Check if open-drain-mode of a GPIO is active 557 * 558 * This checks if open-drain-mode for a GPIO is enabled or not. This method is 559 * optional. 560 * 561 * @desc: GPIO description containing device, offset and flags, 562 * previously returned by gpio_request_by_name() 563 * @return Value of open drain mode for GPIO (0 for inactive, 1 for active) or 564 * -ve on error 565 */ 566 int dm_gpio_get_open_drain(struct gpio_desc *desc); 567 568 /** 569 * dm_gpio_set_open_drain() - Switch open-drain-mode of a GPIO on or off 570 * 571 * This enables or disables open-drain mode for a GPIO. This method is 572 * optional; if the driver does not support it, nothing happens when the method 573 * is called. 574 * 575 * In open-drain mode, instead of actively driving the output (Push-pull 576 * output), the GPIO's pin is connected to the collector (for a NPN transistor) 577 * or the drain (for a MOSFET) of a transistor, respectively. The pin then 578 * either forms an open circuit or a connection to ground, depending on the 579 * state of the transistor. 580 * 581 * @desc: GPIO description containing device, offset and flags, 582 * previously returned by gpio_request_by_name() 583 * @return 0 if OK, -ve on error 584 */ 585 int dm_gpio_set_open_drain(struct gpio_desc *desc, int value); 586 587 /** 588 * dm_gpio_set_dir() - Set the direction for a GPIO 589 * 590 * This sets up the direction according tot the provided flags. It will do 591 * nothing unless the direction is actually specified. 592 * 593 * @desc: GPIO description containing device, offset and flags, 594 * previously returned by gpio_request_by_name() 595 * @return 0 if OK, -ve on error 596 */ 597 int dm_gpio_set_dir(struct gpio_desc *desc); 598 599 /** 600 * dm_gpio_set_dir_flags() - Set direction using specific flags 601 * 602 * This is like dm_gpio_set_dir() except that the flags value is provided 603 * instead of being used from desc->flags. This is needed because in many 604 * cases the GPIO description does not include direction information. 605 * Note that desc->flags is updated by this function. 606 * 607 * @desc: GPIO description containing device, offset and flags, 608 * previously returned by gpio_request_by_name() 609 * @flags: New flags to use 610 * @return 0 if OK, -ve on error, in which case desc->flags is not updated 611 */ 612 int dm_gpio_set_dir_flags(struct gpio_desc *desc, ulong flags); 613 614 /** 615 * gpio_get_number() - Get the global GPIO number of a GPIO 616 * 617 * This should only be used for debugging or interest. It returns the number 618 * that should be used for gpio_get_value() etc. to access this GPIO. 619 * 620 * @desc: GPIO description containing device, offset and flags, 621 * previously returned by gpio_request_by_name() 622 * @return GPIO number, or -ve if not found 623 */ 624 int gpio_get_number(const struct gpio_desc *desc); 625 626 #endif /* _ASM_GENERIC_GPIO_H_ */ 627