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Diffstat (limited to 'zephyr/shim/include/gpio/gpio.h')
| -rw-r--r-- | zephyr/shim/include/gpio/gpio.h | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/zephyr/shim/include/gpio/gpio.h b/zephyr/shim/include/gpio/gpio.h new file mode 100644 index 0000000000..18089e8a8e --- /dev/null +++ b/zephyr/shim/include/gpio/gpio.h @@ -0,0 +1,95 @@ +/* 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_ */ |