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