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.
29 * Request a GPIO. This should be called before any of the other functions
30 * are used on this GPIO.
32 * Note: With driver model, the label is allocated so there is no need for
33 * the caller to preserve it.
35 * @param gp GPIO number
36 * @param label User label for this GPIO
37 * @return 0 if ok, -1 on error
39 int gpio_request(unsigned gpio, const char *label);
42 * Stop using the GPIO. This function should not alter pin configuration.
44 * @param gpio GPIO number
45 * @return 0 if ok, -1 on error
47 int gpio_free(unsigned gpio);
50 * Make a GPIO an input.
52 * @param gpio GPIO number
53 * @return 0 if ok, -1 on error
55 int gpio_direction_input(unsigned gpio);
58 * Make a GPIO an output, and set its value.
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
64 int gpio_direction_output(unsigned gpio, int value);
67 * Get a GPIO's value. This will work whether the GPIO is an input
70 * @param gpio GPIO number
71 * @return 0 if low, 1 if high, -1 on error
73 int gpio_get_value(unsigned gpio);
76 * Set an output GPIO's value. The GPIO must already be an output or
77 * this function may have no effect.
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
83 int gpio_set_value(unsigned gpio, int value);
85 /* State of a GPIO, as reported by get_function() */
89 GPIOF_UNUSED, /* Not claimed */
90 GPIOF_UNKNOWN, /* Not known */
91 GPIOF_FUNC, /* Not used as a GPIO */
99 struct udevice *dev; /* Device, NULL for invalid GPIO */
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 */
107 uint offset; /* GPIO offset within the device */
109 * We could consider adding the GPIO label in here. Possibly we could
110 * use this structure for internal GPIO information.
115 * gpio_get_status() - get the current GPIO status as a string
117 * Obtain the current GPIO status as a string which can be presented to the
118 * user. A typical string is:
120 * "b4: in: 1 [x] sdmmc_cd"
122 * which means this is GPIO bank b, offset 4, currently set to input, current
123 * value 1, [x] means that it is requested and the owner is 'sdmmc_cd'
125 * @dev: Device to check
126 * @offset: Offset of device GPIO to check
127 * @buf: Place to put string
128 * @buffsize: Size of string including \0
130 int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize);
133 * gpio_get_function() - get the current function for a GPIO pin
135 * Note this returns GPIOF_UNUSED if the GPIO is not requested.
137 * @dev: Device to check
138 * @offset: Offset of device GPIO to check
139 * @namep: If non-NULL, this is set to the nane given when the GPIO
140 * was requested, or -1 if it has not been requested
141 * @return -ENODATA if the driver returned an unknown function,
142 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
143 * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the
144 * function from enum gpio_func_t.
146 int gpio_get_function(struct udevice *dev, int offset, const char **namep);
149 * gpio_get_raw_function() - get the current raw function for a GPIO pin
151 * Note this does not return GPIOF_UNUSED - it will always return the GPIO
152 * driver's view of a pin function, even if it is not correctly set up.
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 * Otherwise returns the function from enum gpio_func_t.
162 int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep);
165 * gpio_requestf() - request a GPIO using a format string for the owner
167 * This is a helper function for gpio_request(). It allows you to provide
168 * a printf()-format string for the GPIO owner. It calls gpio_request() with
169 * the string that is created
171 int gpio_requestf(unsigned gpio, const char *fmt, ...)
172 __attribute__ ((format (__printf__, 2, 3)));
175 * struct struct dm_gpio_ops - Driver model GPIO operations
177 * Refer to functions above for description. These function largely copy
180 * This is trying to be close to Linux GPIO API. Once the U-Boot uses the
181 * new DM GPIO API, this should be really easy to flip over to the Linux
182 * GPIO API-alike interface.
184 * Also it would be useful to standardise additional functions like
185 * pullup, slew rate and drive strength.
187 * gpio_request)( and gpio_free() are optional - if NULL then they will
190 * Note that @offset is the offset from the base GPIO of the device. So
191 * offset 0 is the device's first GPIO and offset o-1 is the last GPIO,
192 * where o is the number of GPIO lines controlled by the device. A device
193 * is typically used to control a single bank of GPIOs. Within complex
194 * SoCs there may be many banks and therefore many devices all referring
195 * to the different IO addresses within the SoC.
197 * The uclass combines all GPIO devices together to provide a consistent
198 * numbering from 0 to n-1, where n is the number of GPIOs in total across
199 * all devices. Be careful not to confuse offset with gpio in the parameters.
202 int (*request)(struct udevice *dev, unsigned offset, const char *label);
203 int (*free)(struct udevice *dev, unsigned offset);
204 int (*direction_input)(struct udevice *dev, unsigned offset);
205 int (*direction_output)(struct udevice *dev, unsigned offset,
207 int (*get_value)(struct udevice *dev, unsigned offset);
208 int (*set_value)(struct udevice *dev, unsigned offset, int value);
210 * get_function() Get the GPIO function
212 * @dev: Device to check
213 * @offset: GPIO offset within that device
214 * @return current function - GPIOF_...
216 int (*get_function)(struct udevice *dev, unsigned offset);
220 * struct gpio_dev_priv - information about a device used by the uclass
222 * The uclass combines all active GPIO devices into a unified numbering
223 * scheme. To do this it maintains some private information about each
226 * To implement driver model support in your GPIO driver, add a probe
227 * handler, and set @gpio_count and @bank_name correctly in that handler.
228 * This tells the uclass the name of the GPIO bank and the number of GPIOs
231 * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called
233 * @gpio_count: Number of GPIOs in this device
234 * @gpio_base: Base GPIO number for this device. For the first active device
235 * this will be 0; the numbering for others will follow sequentially so that
236 * @gpio_base for device 1 will equal the number of GPIOs in device 0.
237 * @name: Array of pointers to the name for each GPIO in this bank. The
238 * value of the pointer will be NULL if the GPIO has not been claimed.
240 struct gpio_dev_priv {
241 const char *bank_name;
247 /* Access the GPIO operations for a device */
248 #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops)
251 * gpio_get_bank_info - Return information about a GPIO bank/device
253 * This looks up a device and returns both its GPIO base name and the number
254 * of GPIOs it controls.
256 * @dev: Device to look up
257 * @offset_count: Returns number of GPIOs within this bank
258 * @return bank name of this device
260 const char *gpio_get_bank_info(struct udevice *dev, int *offset_count);
263 * gpio_lookup_name - Look up a GPIO name and return its details
265 * This is used to convert a named GPIO into a device, offset and GPIO
268 * @name: GPIO name to look up
269 * @devp: Returns pointer to device which contains this GPIO
270 * @offsetp: Returns the offset number within this device
271 * @gpiop: Returns the absolute GPIO number, numbered from 0
273 int gpio_lookup_name(const char *name, struct udevice **devp,
274 unsigned int *offsetp, unsigned int *gpiop);
277 * get_gpios() - Turn the values of a list of GPIOs into an integer
279 * This puts the value of the first GPIO into bit 0, the second into bit 1,
280 * etc. then returns the resulting integer.
282 * @gpio_list: List of GPIOs to collect
283 * @return resulting integer value
285 unsigned gpio_get_values_as_int(const int *gpio_list);
287 #endif /* _ASM_GENERIC_GPIO_H_ */