/* -*- mode:c -*-
 *
 * Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

/*
 * 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.  Similarly, the port parameter has GPIO_ prepended to
 * it before it is used to initialize the port base address of a gpio_info
 * struct.  The pin number is used to create a bitmask.  The flags and signal
 * parameters are passed on to the gpio_info directly.
 */
#ifndef GPIO
#define GPIO(name, port, pin, flags, signal)
#endif

/*
 * 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, the second parameter is the
 * bitmask of pins to be assigned.
 */
#ifndef ALTERNATE
#define ALTERNATE(port, mask, function, module, flags)
#endif

/*
 * 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 DUMMY_GPIO_BANK and a bitmask of zero.  The chip GPIO layer is
 * implemented such that writes to and reads from DUMMY_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 ALTERNATE
#undef UNIMPLEMENTED