2 * Copyright (c) 2011 The Chromium OS Authors.
3 * Copyright (c) 2011, NVIDIA Corp. All rights reserved.
4 * SPDX-License-Identifier: GPL-2.0+
7 #ifndef _ASM_GENERIC_GPIO_H_
8 #define _ASM_GENERIC_GPIO_H_
11 * Generic GPIO API for U-Boot
13 * GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined
14 * by the SOC/architecture.
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.
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.
30 GPIOFLAG_OUTPUT_INIT_LOW,
31 GPIOFLAG_OUTPUT_INIT_HIGH,
36 enum gpio_flags flags;
41 * Request a GPIO. This should be called before any of the other functions
42 * are used on this GPIO.
44 * Note: With driver model, the label is allocated so there is no need for
45 * the caller to preserve it.
47 * @param gp GPIO number
48 * @param label User label for this GPIO
49 * @return 0 if ok, -1 on error
51 int gpio_request(unsigned gpio, const char *label);
54 * Request a GPIO and configure it
55 * @param gpios pointer to array of gpio defs
56 * @param count number of GPIOs to set up
58 int gpio_request_one(unsigned gpio, enum gpio_flags flags, const char *label);
61 * Request a set of GPIOs and configure them
62 * @param gpios pointer to array of gpio defs
63 * @param count number of GPIOs to set up
65 int gpio_request_array(const struct gpio *gpios, int count);
68 * Stop using the GPIO. This function should not alter pin configuration.
70 * @param gpio GPIO number
71 * @return 0 if ok, -1 on error
73 int gpio_free(unsigned gpio);
76 * Release a set of GPIOs
77 * @param gpios pointer to array of gpio defs
78 * @param count number of GPIOs to set up
80 int gpio_free_array(const struct gpio *gpios, int count);
83 * Make a GPIO an input.
85 * @param gpio GPIO number
86 * @return 0 if ok, -1 on error
88 int gpio_direction_input(unsigned gpio);
91 * Make a GPIO an output, and set its value.
93 * @param gpio GPIO number
94 * @param value GPIO value (0 for low or 1 for high)
95 * @return 0 if ok, -1 on error
97 int gpio_direction_output(unsigned gpio, int value);
100 * Get a GPIO's value. This will work whether the GPIO is an input
103 * @param gpio GPIO number
104 * @return 0 if low, 1 if high, -1 on error
106 int gpio_get_value(unsigned gpio);
109 * Set an output GPIO's value. The GPIO must already be an output or
110 * this function may have no effect.
112 * @param gpio GPIO number
113 * @param value GPIO value (0 for low or 1 for high)
114 * @return 0 if ok, -1 on error
116 int gpio_set_value(unsigned gpio, int value);
118 /* State of a GPIO, as reported by get_function() */
122 GPIOF_UNUSED, /* Not claimed */
123 GPIOF_UNKNOWN, /* Not known */
124 GPIOF_FUNC, /* Not used as a GPIO */
132 * gpio_get_status() - get the current GPIO status as a string
134 * Obtain the current GPIO status as a string which can be presented to the
135 * user. A typical string is:
137 * "b4: in: 1 [x] sdmmc_cd"
139 * which means this is GPIO bank b, offset 4, currently set to input, current
140 * value 1, [x] means that it is requested and the owner is 'sdmmc_cd'
142 * @dev: Device to check
143 * @offset: Offset of device GPIO to check
144 * @buf: Place to put string
145 * @buffsize: Size of string including \0
147 int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize);
150 * gpio_get_function() - get the current function for a GPIO pin
152 * Note this returns GPIOF_UNUSED if the GPIO is not requested.
154 * @dev: Device to check
155 * @offset: Offset of device GPIO to check
156 * @namep: If non-NULL, this is set to the nane given when the GPIO
157 * was requested, or -1 if it has not been requested
158 * @return -ENODATA if the driver returned an unknown function,
159 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
160 * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the
161 * function from enum gpio_func_t.
163 int gpio_get_function(struct udevice *dev, int offset, const char **namep);
166 * gpio_get_raw_function() - get the current raw function for a GPIO pin
168 * Note this does not return GPIOF_UNUSED - it will always return the GPIO
169 * driver's view of a pin function, even if it is not correctly set up.
171 * @dev: Device to check
172 * @offset: Offset of device GPIO to check
173 * @namep: If non-NULL, this is set to the nane given when the GPIO
174 * was requested, or -1 if it has not been requested
175 * @return -ENODATA if the driver returned an unknown function,
176 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
177 * Otherwise returns the function from enum gpio_func_t.
179 int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep);
182 * gpio_requestf() - request a GPIO using a format string for the owner
184 * This is a helper function for gpio_request(). It allows you to provide
185 * a printf()-format string for the GPIO owner. It calls gpio_request() with
186 * the string that is created
188 int gpio_requestf(unsigned gpio, const char *fmt, ...)
189 __attribute__ ((format (__printf__, 2, 3)));
192 * struct struct dm_gpio_ops - Driver model GPIO operations
194 * Refer to functions above for description. These function largely copy
197 * This is trying to be close to Linux GPIO API. Once the U-Boot uses the
198 * new DM GPIO API, this should be really easy to flip over to the Linux
199 * GPIO API-alike interface.
201 * Also it would be useful to standardise additional functions like
202 * pullup, slew rate and drive strength.
204 * gpio_request)( and gpio_free() are optional - if NULL then they will
207 * Note that @offset is the offset from the base GPIO of the device. So
208 * offset 0 is the device's first GPIO and offset o-1 is the last GPIO,
209 * where o is the number of GPIO lines controlled by the device. A device
210 * is typically used to control a single bank of GPIOs. Within complex
211 * SoCs there may be many banks and therefore many devices all referring
212 * to the different IO addresses within the SoC.
214 * The uclass combines all GPIO devices together to provide a consistent
215 * numbering from 0 to n-1, where n is the number of GPIOs in total across
216 * all devices. Be careful not to confuse offset with gpio in the parameters.
219 int (*request)(struct udevice *dev, unsigned offset, const char *label);
220 int (*free)(struct udevice *dev, unsigned offset);
221 int (*direction_input)(struct udevice *dev, unsigned offset);
222 int (*direction_output)(struct udevice *dev, unsigned offset,
224 int (*get_value)(struct udevice *dev, unsigned offset);
225 int (*set_value)(struct udevice *dev, unsigned offset, int value);
227 * get_function() Get the GPIO function
229 * @dev: Device to check
230 * @offset: GPIO offset within that device
231 * @return current function - GPIOF_...
233 int (*get_function)(struct udevice *dev, unsigned offset);
237 * struct gpio_dev_priv - information about a device used by the uclass
239 * The uclass combines all active GPIO devices into a unified numbering
240 * scheme. To do this it maintains some private information about each
243 * To implement driver model support in your GPIO driver, add a probe
244 * handler, and set @gpio_count and @bank_name correctly in that handler.
245 * This tells the uclass the name of the GPIO bank and the number of GPIOs
248 * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called
250 * @gpio_count: Number of GPIOs in this device
251 * @gpio_base: Base GPIO number for this device. For the first active device
252 * this will be 0; the numbering for others will follow sequentially so that
253 * @gpio_base for device 1 will equal the number of GPIOs in device 0.
254 * @name: Array of pointers to the name for each GPIO in this bank. The
255 * value of the pointer will be NULL if the GPIO has not been claimed.
257 struct gpio_dev_priv {
258 const char *bank_name;
264 /* Access the GPIO operations for a device */
265 #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops)
268 * gpio_get_bank_info - Return information about a GPIO bank/device
270 * This looks up a device and returns both its GPIO base name and the number
271 * of GPIOs it controls.
273 * @dev: Device to look up
274 * @offset_count: Returns number of GPIOs within this bank
275 * @return bank name of this device
277 const char *gpio_get_bank_info(struct udevice *dev, int *offset_count);
280 * gpio_lookup_name - Look up a GPIO name and return its details
282 * This is used to convert a named GPIO into a device, offset and GPIO
285 * @name: GPIO name to look up
286 * @devp: Returns pointer to device which contains this GPIO
287 * @offsetp: Returns the offset number within this device
288 * @gpiop: Returns the absolute GPIO number, numbered from 0
290 int gpio_lookup_name(const char *name, struct udevice **devp,
291 unsigned int *offsetp, unsigned int *gpiop);
294 * get_gpios() - Turn the values of a list of GPIOs into an integer
296 * This puts the value of the first GPIO into bit 0, the second into bit 1,
297 * etc. then returns the resulting integer.
299 * @gpio_list: List of GPIOs to collect
300 * @return resulting integer value
302 unsigned gpio_get_values_as_int(const int *gpio_list);
304 #endif /* _ASM_GENERIC_GPIO_H_ */