| /* |
| * Copyright (c) 2011 The Chromium OS Authors. |
| * Copyright (c) 2011, NVIDIA Corp. All rights reserved. |
| * SPDX-License-Identifier: GPL-2.0+ |
| */ |
| |
| #ifndef _ASM_GENERIC_GPIO_H_ |
| #define _ASM_GENERIC_GPIO_H_ |
| |
| /* |
| * Generic GPIO API for U-Boot |
| * |
| * GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined |
| * by the SOC/architecture. |
| * |
| * Each GPIO can be an input or output. If an input then its value can |
| * be read as 0 or 1. If an output then its value can be set to 0 or 1. |
| * If you try to write an input then the value is undefined. If you try |
| * to read an output, barring something very unusual, you will get |
| * back the value of the output that you previously set. |
| * |
| * In some cases the operation may fail, for example if the GPIO number |
| * is out of range, or the GPIO is not available because its pin is |
| * being used by another function. In that case, functions may return |
| * an error value of -1. |
| */ |
| |
| /** |
| * Request a gpio. This should be called before any of the other functions |
| * are used on this gpio. |
| * |
| * @param gp GPIO number |
| * @param label User label for this GPIO |
| * @return 0 if ok, -1 on error |
| */ |
| int gpio_request(unsigned gpio, const char *label); |
| |
| /** |
| * Stop using the GPIO. This function should not alter pin configuration. |
| * |
| * @param gpio GPIO number |
| * @return 0 if ok, -1 on error |
| */ |
| int gpio_free(unsigned gpio); |
| |
| /** |
| * Make a GPIO an input. |
| * |
| * @param gpio GPIO number |
| * @return 0 if ok, -1 on error |
| */ |
| int gpio_direction_input(unsigned gpio); |
| |
| /** |
| * Make a GPIO an output, and set its value. |
| * |
| * @param gpio GPIO number |
| * @param value GPIO value (0 for low or 1 for high) |
| * @return 0 if ok, -1 on error |
| */ |
| int gpio_direction_output(unsigned gpio, int value); |
| |
| /** |
| * Get a GPIO's value. This will work whether the GPIO is an input |
| * or an output. |
| * |
| * @param gpio GPIO number |
| * @return 0 if low, 1 if high, -1 on error |
| */ |
| int gpio_get_value(unsigned gpio); |
| |
| /** |
| * Set an output GPIO's value. The GPIO must already be an output or |
| * this function may have no effect. |
| * |
| * @param gpio GPIO number |
| * @param value GPIO value (0 for low or 1 for high) |
| * @return 0 if ok, -1 on error |
| */ |
| int gpio_set_value(unsigned gpio, int value); |
| |
| /* State of a GPIO, as reported by get_function() */ |
| enum { |
| GPIOF_INPUT = 0, |
| GPIOF_OUTPUT, |
| GPIOF_UNUSED, /* Not claimed */ |
| GPIOF_UNKNOWN, /* Not known */ |
| GPIOF_FUNC, /* Not used as a GPIO */ |
| |
| GPIOF_COUNT, |
| }; |
| |
| struct udevice; |
| |
| /** |
| * struct struct dm_gpio_ops - Driver model GPIO operations |
| * |
| * Refer to functions above for description. These function largely copy |
| * the old API. |
| * |
| * This is trying to be close to Linux GPIO API. Once the U-Boot uses the |
| * new DM GPIO API, this should be really easy to flip over to the Linux |
| * GPIO API-alike interface. |
| * |
| * Akso it would be useful to standardise additional functions like |
| * pullup, slew rate and drive strength. |
| * |
| * gpio_request)( and gpio_free() are optional - if NULL then they will |
| * not be called. |
| * |
| * Note that @offset is the offset from the base GPIO of the device. So |
| * offset 0 is the device's first GPIO and offset o-1 is the last GPIO, |
| * where o is the number of GPIO lines controlled by the device. A device |
| * is typically used to control a single bank of GPIOs. Within complex |
| * SoCs there may be many banks and therefore many devices all referring |
| * to the different IO addresses within the SoC. |
| * |
| * The uclass combines all GPIO devices togther to provide a consistent |
| * numbering from 0 to n-1, where n is the number of GPIOs in total across |
| * all devices. Be careful not to confuse offset with gpio in the parameters. |
| */ |
| struct dm_gpio_ops { |
| int (*request)(struct udevice *dev, unsigned offset, const char *label); |
| int (*free)(struct udevice *dev, unsigned offset); |
| int (*direction_input)(struct udevice *dev, unsigned offset); |
| int (*direction_output)(struct udevice *dev, unsigned offset, |
| int value); |
| int (*get_value)(struct udevice *dev, unsigned offset); |
| int (*set_value)(struct udevice *dev, unsigned offset, int value); |
| /** |
| * get_function() Get the GPIO function |
| * |
| * @dev: Device to check |
| * @offset: GPIO offset within that device |
| * @return current function - GPIOF_... |
| */ |
| int (*get_function)(struct udevice *dev, unsigned offset); |
| int (*get_state)(struct udevice *dev, unsigned offset, char *state, |
| int maxlen); |
| }; |
| |
| /** |
| * struct gpio_dev_priv - information about a device used by the uclass |
| * |
| * The uclass combines all active GPIO devices into a unified numbering |
| * scheme. To do this it maintains some private information aobut each |
| * device. |
| * |
| * To implement driver model support in your GPIO driver, add a probe |
| * handler, and set @gpio_count and @bank_name correctly in that handler. |
| * This tells the uclass the name of the GPIO bank and the number of GPIOs |
| * it contains. |
| * |
| * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called |
| * 'A0', 'A1', etc. |
| * @gpio_count: Number of GPIOs in this device |
| * @gpio_base: Base GPIO number for this device. For the first active device |
| * this will be 0; the numbering for others will follow sequentially so that |
| * @gpio_base for device 1 will equal the number of GPIOs in device 0. |
| */ |
| struct gpio_dev_priv { |
| const char *bank_name; |
| unsigned gpio_count; |
| unsigned gpio_base; |
| }; |
| |
| /* Access the GPIO operations for a device */ |
| #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops) |
| |
| /** |
| * gpio_get_bank_info - Return information about a GPIO bank/device |
| * |
| * This looks up a device and returns both its GPIO base name and the number |
| * of GPIOs it controls. |
| * |
| * @dev: Device to look up |
| * @offset_count: Returns number of GPIOs within this bank |
| * @return bank name of this device |
| */ |
| const char *gpio_get_bank_info(struct udevice *dev, int *offset_count); |
| |
| /** |
| * gpio_lookup_name - Look up a GPIO name and return its details |
| * |
| * This is used to convert a named GPIO into a device, offset and GPIO |
| * number. |
| * |
| * @name: GPIO name to look up |
| * @devp: Returns pointer to device which contains this GPIO |
| * @offsetp: Returns the offset number within this device |
| * @gpiop: Returns the absolute GPIO number, numbered from 0 |
| */ |
| int gpio_lookup_name(const char *name, struct udevice **devp, |
| unsigned int *offsetp, unsigned int *gpiop); |
| |
| #endif /* _ASM_GENERIC_GPIO_H_ */ |