1 /*
2 * Copyright (c) 2019 Nordic Semiconductor ASA.
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <zephyr/drivers/gpio.h>
8 #include <zephyr/drivers/uart.h>
9 #include <zephyr/device.h>
10 #include <zephyr/devicetree.h>
11 #include <zephyr/kernel.h>
12
13 #define RESET_NODE DT_NODELABEL(nrf52840_reset)
14
15 #if DT_NODE_HAS_STATUS_OKAY(RESET_NODE)
16
17 #define RESET_GPIO_CTRL DT_GPIO_CTLR(RESET_NODE, gpios)
18 #define RESET_GPIO_PIN DT_GPIO_PIN(RESET_NODE, gpios)
19 #define RESET_GPIO_FLAGS DT_GPIO_FLAGS(RESET_NODE, gpios)
20
bt_hci_transport_setup(const struct device * h4)21 int bt_hci_transport_setup(const struct device *h4)
22 {
23 int err;
24 char c;
25 const struct device *const port = DEVICE_DT_GET(RESET_GPIO_CTRL);
26
27 if (!device_is_ready(port)) {
28 return -EIO;
29 }
30
31 /* Configure pin as output and initialize it to inactive state. */
32 err = gpio_pin_configure(port, RESET_GPIO_PIN,
33 RESET_GPIO_FLAGS | GPIO_OUTPUT_INACTIVE);
34 if (err) {
35 return err;
36 }
37
38 /* Reset the nRF52840 and let it wait until the pin is inactive again
39 * before running to main to ensure that it won't send any data until
40 * the H4 device is setup and ready to receive.
41 */
42 err = gpio_pin_set(port, RESET_GPIO_PIN, 1);
43 if (err) {
44 return err;
45 }
46
47 /* Wait for the nRF52840 peripheral to stop sending data.
48 *
49 * It is critical (!) to wait here, so that all bytes
50 * on the lines are received and drained correctly.
51 */
52 k_sleep(K_MSEC(10));
53
54 /* Drain bytes */
55 while (h4 && uart_fifo_read(h4, &c, 1)) {
56 continue;
57 }
58
59 /* We are ready, let the nRF52840 run to main */
60 err = gpio_pin_set(port, RESET_GPIO_PIN, 0);
61 if (err) {
62 return err;
63 }
64
65 return 0;
66 }
67
68 #endif /* DT_NODE_HAS_STATUS_OKAY(RESET_NODE) */
69
