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/* Copyright 2021 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.
*/
#ifndef ZEPHYR_SHIM_INCLUDE_GPIO_GPIO_H_
#define ZEPHYR_SHIM_INCLUDE_GPIO_GPIO_H_
#include <device.h>
#include <devicetree.h>
/* Information about each unused pin in the 'unused-pins' device tree node. */
struct unused_pin_config {
/* Device name of a unused gpio pin */
const char *dev_name;
/* Bit number of pin within a unused gpio pin */
gpio_pin_t pin;
/* Config flags of unused gpio pin */
gpio_flags_t flags;
};
/**
* @brief Set proper configuration for all unused pins.
*
* This function loops through all unused GPIOs in the node of "unused-gpios"
* in the device tree file to set proper configuration. If the GPIO flag is 0,
* set the GPIOs default setting for floating IOs to improve the power
* consumption.
*
* @return 0 If successful.
* @retval -ENOTSUP Not supported gpio device.
* @retval -EIO I/O error when accessing an external GPIO chip.
*/
int gpio_config_unused_pins(void) __attribute__((weak));
#if DT_NODE_EXISTS(DT_PATH(unused_pins))
/**
* @brief Get a node from path '/unused-pins' which has a prop 'unused-gpios'.
* It contains unused GPIOs and chip vendor needs to configure them for
* better power consumption in the lowest power state.
*
* @return node identifier with that path.
*/
#define UNUSED_PINS_LIST DT_PATH(unused_pins)
/**
* @brief Length of 'unused-gpios' property
*
* @return length of 'unused-gpios' prop which type is 'phandle-array'
*/
#define UNUSED_GPIOS_LIST_LEN DT_PROP_LEN(UNUSED_PINS_LIST, unused_gpios)
/**
* @brief Construct a unused_pin_config structure from 'unused-gpios' property
* at index 'i'
*
* @param i index of 'unused-gpios' prop which type is 'phandles-array'
* @return unused_pin_config item at index 'i'
*/
#define UNUSED_GPIO_CONFIG_BY_IDX(i, _) \
{ \
.dev_name = DT_GPIO_LABEL_BY_IDX(UNUSED_PINS_LIST, \
unused_gpios, i), \
.pin = DT_GPIO_PIN_BY_IDX(UNUSED_PINS_LIST, unused_gpios, i), \
.flags = DT_GPIO_FLAGS_BY_IDX(UNUSED_PINS_LIST, unused_gpios, \
i), \
},
/**
* @brief Macro function to construct a list of unused_pin_config items by
* UTIL_LISTIFY func.
*
* Example devicetree fragment:
* / {
* unused-pins {
* compatible = "unused-gpios";
* unused-gpios = <&gpio5 1 0>,
* <&gpiod 0 0>,
* <&gpiof 3 0>;
* };
*
* Example usage:
* static const struct unused_pin_config unused_pin_configs[] = {
* UNUSED_GPIO_CONFIG_LIST
* };
*
* @return a list of unused_pin_config items
*/
#define UNUSED_GPIO_CONFIG_LIST \
UTIL_LISTIFY(UNUSED_GPIOS_LIST_LEN, UNUSED_GPIO_CONFIG_BY_IDX, _)
#else
#define UNUSED_GPIO_CONFIG_LIST /* Nothing if no 'unused-pins' node */
#endif /* unused_pins */
#endif /* ZEPHYR_SHIM_INCLUDE_GPIO_GPIO_H_ */
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