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 /** 99 * gpio_get_status() - get the current GPIO status as a string 100 * 101 * Obtain the current GPIO status as a string which can be presented to the 102 * user. A typical string is: 103 * 104 * "b4: in: 1 [x] sdmmc_cd" 105 * 106 * which means this is GPIO bank b, offset 4, currently set to input, current 107 * value 1, [x] means that it is requested and the owner is 'sdmmc_cd' 108 * 109 * @dev: Device to check 110 * @offset: Offset of device GPIO to check 111 * @buf: Place to put string 112 * @buffsize: Size of string including \0 113 */ 114 int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize); 115 116 /** 117 * gpio_get_function() - get the current function for a GPIO pin 118 * 119 * Note this returns GPIOF_UNUSED if the GPIO is not requested. 120 * 121 * @dev: Device to check 122 * @offset: Offset of device GPIO to check 123 * @namep: If non-NULL, this is set to the nane given when the GPIO 124 * was requested, or -1 if it has not been requested 125 * @return -ENODATA if the driver returned an unknown function, 126 * -ENODEV if the device is not active, -EINVAL if the offset is invalid. 127 * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the 128 * function from enum gpio_func_t. 129 */ 130 int gpio_get_function(struct udevice *dev, int offset, const char **namep); 131 132 /** 133 * gpio_get_raw_function() - get the current raw function for a GPIO pin 134 * 135 * Note this does not return GPIOF_UNUSED - it will always return the GPIO 136 * driver's view of a pin function, even if it is not correctly set up. 137 * 138 * @dev: Device to check 139 * @offset: Offset of device GPIO to check 140 * @namep: If non-NULL, this is set to the nane given when the GPIO 141 * was requested, or -1 if it has not been requested 142 * @return -ENODATA if the driver returned an unknown function, 143 * -ENODEV if the device is not active, -EINVAL if the offset is invalid. 144 * Otherwise returns the function from enum gpio_func_t. 145 */ 146 int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep); 147 148 /** 149 * gpio_requestf() - request a GPIO using a format string for the owner 150 * 151 * This is a helper function for gpio_request(). It allows you to provide 152 * a printf()-format string for the GPIO owner. It calls gpio_request() with 153 * the string that is created 154 */ 155 int gpio_requestf(unsigned gpio, const char *fmt, ...) 156 __attribute__ ((format (__printf__, 2, 3))); 157 158 /** 159 * struct struct dm_gpio_ops - Driver model GPIO operations 160 * 161 * Refer to functions above for description. These function largely copy 162 * the old API. 163 * 164 * This is trying to be close to Linux GPIO API. Once the U-Boot uses the 165 * new DM GPIO API, this should be really easy to flip over to the Linux 166 * GPIO API-alike interface. 167 * 168 * Also it would be useful to standardise additional functions like 169 * pullup, slew rate and drive strength. 170 * 171 * gpio_request)( and gpio_free() are optional - if NULL then they will 172 * not be called. 173 * 174 * Note that @offset is the offset from the base GPIO of the device. So 175 * offset 0 is the device's first GPIO and offset o-1 is the last GPIO, 176 * where o is the number of GPIO lines controlled by the device. A device 177 * is typically used to control a single bank of GPIOs. Within complex 178 * SoCs there may be many banks and therefore many devices all referring 179 * to the different IO addresses within the SoC. 180 * 181 * The uclass combines all GPIO devices together to provide a consistent 182 * numbering from 0 to n-1, where n is the number of GPIOs in total across 183 * all devices. Be careful not to confuse offset with gpio in the parameters. 184 */ 185 struct dm_gpio_ops { 186 int (*request)(struct udevice *dev, unsigned offset, const char *label); 187 int (*free)(struct udevice *dev, unsigned offset); 188 int (*direction_input)(struct udevice *dev, unsigned offset); 189 int (*direction_output)(struct udevice *dev, unsigned offset, 190 int value); 191 int (*get_value)(struct udevice *dev, unsigned offset); 192 int (*set_value)(struct udevice *dev, unsigned offset, int value); 193 /** 194 * get_function() Get the GPIO function 195 * 196 * @dev: Device to check 197 * @offset: GPIO offset within that device 198 * @return current function - GPIOF_... 199 */ 200 int (*get_function)(struct udevice *dev, unsigned offset); 201 }; 202 203 /** 204 * struct gpio_dev_priv - information about a device used by the uclass 205 * 206 * The uclass combines all active GPIO devices into a unified numbering 207 * scheme. To do this it maintains some private information about each 208 * device. 209 * 210 * To implement driver model support in your GPIO driver, add a probe 211 * handler, and set @gpio_count and @bank_name correctly in that handler. 212 * This tells the uclass the name of the GPIO bank and the number of GPIOs 213 * it contains. 214 * 215 * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called 216 * 'A0', 'A1', etc. 217 * @gpio_count: Number of GPIOs in this device 218 * @gpio_base: Base GPIO number for this device. For the first active device 219 * this will be 0; the numbering for others will follow sequentially so that 220 * @gpio_base for device 1 will equal the number of GPIOs in device 0. 221 * @name: Array of pointers to the name for each GPIO in this bank. The 222 * value of the pointer will be NULL if the GPIO has not been claimed. 223 */ 224 struct gpio_dev_priv { 225 const char *bank_name; 226 unsigned gpio_count; 227 unsigned gpio_base; 228 char **name; 229 }; 230 231 /* Access the GPIO operations for a device */ 232 #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops) 233 234 /** 235 * gpio_get_bank_info - Return information about a GPIO bank/device 236 * 237 * This looks up a device and returns both its GPIO base name and the number 238 * of GPIOs it controls. 239 * 240 * @dev: Device to look up 241 * @offset_count: Returns number of GPIOs within this bank 242 * @return bank name of this device 243 */ 244 const char *gpio_get_bank_info(struct udevice *dev, int *offset_count); 245 246 /** 247 * gpio_lookup_name - Look up a GPIO name and return its details 248 * 249 * This is used to convert a named GPIO into a device, offset and GPIO 250 * number. 251 * 252 * @name: GPIO name to look up 253 * @devp: Returns pointer to device which contains this GPIO 254 * @offsetp: Returns the offset number within this device 255 * @gpiop: Returns the absolute GPIO number, numbered from 0 256 */ 257 int gpio_lookup_name(const char *name, struct udevice **devp, 258 unsigned int *offsetp, unsigned int *gpiop); 259 260 /** 261 * get_gpios() - Turn the values of a list of GPIOs into an integer 262 * 263 * This puts the value of the first GPIO into bit 0, the second into bit 1, 264 * etc. then returns the resulting integer. 265 * 266 * @gpio_list: List of GPIOs to collect 267 * @return resulting integer value 268 */ 269 unsigned gpio_get_values_as_int(const int *gpio_list); 270 271 #endif /* _ASM_GENERIC_GPIO_H_ */ 272