zephyr/boards/nordic/nrf9160dk/nrf52840_reset.c

69 lines
1.6 KiB
C

/*
* Copyright (c) 2019 Nordic Semiconductor ASA.
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/drivers/gpio.h>
#include <zephyr/drivers/uart.h>
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <zephyr/kernel.h>
#define RESET_NODE DT_NODELABEL(nrf52840_reset)
#if DT_NODE_HAS_STATUS_OKAY(RESET_NODE)
#define RESET_GPIO_CTRL DT_GPIO_CTLR(RESET_NODE, gpios)
#define RESET_GPIO_PIN DT_GPIO_PIN(RESET_NODE, gpios)
#define RESET_GPIO_FLAGS DT_GPIO_FLAGS(RESET_NODE, gpios)
int bt_hci_transport_setup(const struct device *h4)
{
int err;
char c;
const struct device *const port = DEVICE_DT_GET(RESET_GPIO_CTRL);
if (!device_is_ready(port)) {
return -EIO;
}
/* Configure pin as output and initialize it to inactive state. */
err = gpio_pin_configure(port, RESET_GPIO_PIN,
RESET_GPIO_FLAGS | GPIO_OUTPUT_INACTIVE);
if (err) {
return err;
}
/* Reset the nRF52840 and let it wait until the pin is inactive again
* before running to main to ensure that it won't send any data until
* the H4 device is setup and ready to receive.
*/
err = gpio_pin_set(port, RESET_GPIO_PIN, 1);
if (err) {
return err;
}
/* Wait for the nRF52840 peripheral to stop sending data.
*
* It is critical (!) to wait here, so that all bytes
* on the lines are received and drained correctly.
*/
k_sleep(K_MSEC(10));
/* Drain bytes */
while (h4 && uart_fifo_read(h4, &c, 1)) {
continue;
}
/* We are ready, let the nRF52840 run to main */
err = gpio_pin_set(port, RESET_GPIO_PIN, 0);
if (err) {
return err;
}
return 0;
}
#endif /* DT_NODE_HAS_STATUS_OKAY(RESET_NODE) */