xref: /aosp_15_r20/external/gsc-utils/include/gpio.wrap (revision 4f2df630800bdcf1d4f0decf95d8a1cb87344f5f)

/* -*- mode:c -*-
 *
 * Copyright 2014 The ChromiumOS Authors
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

/**
 * @file gpio.wrap
 * @brief Include the board specific *gpio.inc* file.
 *
 * This file is included in many different contexts.
 * The macros defined outside of the file (before including)
 * determine what parts of *gpio.inc* will be emitted.
 *
 * @see include/gpio_list.h
 * @see common/gpio.c
 * @see include/gpio_signal.h
 */

#ifndef GPIO_PIN
#error "Your architecture must define GPIO_PIN and it did not."
#endif

#ifndef GPIO_PIN_MASK
#error "Your architecture must define GPIO_PIN_MASK and it did not."
#endif

/**
 * @def GPIO
 * @brief The GPIO macro is used to define a new GPIO pin name and function.
 *
 * The name is used to populate the gpio_signal enum by first
 * prepending GPIO_ to the name.  It is also used to construct the
 * string name that is presented in the shell interface.  The pin
 * parameter should use PIN macro and will be expand to GPIO_PIN
 * defined on each board.  The flags parameter is passed on to the
 * gpio_info directly.
 */
#ifndef GPIO
#define GPIO(name, pin, flags)
#endif

/**
 * @def GPIO_INT
 * @brief The GPIO_INT macro is used to define a GPIOs that have an IRQ handler.
 *
 * The IRQ handler pointers are stored as elements in the gpio_irq_handlers
 * array.
 */
#ifndef GPIO_INT
#define GPIO_INT(name, pin, flags, signal)
#endif

/**
 * @def ALTERNATE
 * @brief The ALTERNATE macro is used associate a GPIO with an alternate
 *        function.
 *
 * Alternate functions allow hardware peripherals access to GPIO pins.
 * Modules use gpio_config_module to enable and disable the alternate functions
 * of GPIOs assigned to that module.  So if the module parameter is MODULE_UART
 * then when the uart_init function is called the GPIO will be switched to its
 * alternate function mode.  The function parameter is chip/variant specific
 * and will usually need to be looked up in the datasheet.  The flags parameter
 * has the same meaning as in the GPIO macro above.  This macro can assign
 * multiple pins on the same port to a module, pinmasks should use PIN_MASK
 * and will be expanded as GPIO_PIN_MASK defined in each config_chip.h.
 */
#ifndef ALTERNATE
#define ALTERNATE(pinmask, function, module, flags)
#endif

/**
 * @def UNIMPLEMENTED
 * @brief The UNIMPLEMENTED macro is used to define a GPIO that doesn't actually exist.
 *
 * Some GPIO names are well known and used by generic code, ENTERING_RW and WP_L
 * are examples.  If a particular board doesn't have a GPIO assigned to such a
 * function/name then it should specify that that GPIO is not implemented using
 * the UNIMPLEMENTED macro below in the board gpio.inc file.  This macro creates
 * an entry in the gpio_signal enum and the gpio_list array that is initialized
 * to use the PLACEHOLDER_GPIO_BANK and a bitmask of zero.  The chip GPIO layer
 * is implemented such that writes to and reads from PLACEHOLDER_GPIO_BANK with
 * a bitmask of zero are harmless.
 *
 * This allows common code that expects these GPIOs to exist to compile and have
 * some reduced functionality.
 */
#ifndef UNIMPLEMENTED
#define UNIMPLEMENTED(name)
#endif

#include "gpio.inc"

/*
 * Once the gpio.inc file has been included these macros are no longer needed.
 */
#undef GPIO
#undef GPIO_INT
#undef ALTERNATE
#undef UNIMPLEMENTED