| /* |
| * Copyright (c) 2019 Nordic Semiconductor ASA. |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| */ |
| |
| #include <drivers/gpio.h> |
| #include <drivers/uart.h> |
| #include <device.h> |
| |
| #define RESET_PIN CONFIG_BOARD_NRF52840_GPIO_RESET_PIN |
| |
| /* Must be a pin from 17 to 23. |
| * Only those can be connected to the nRF52840. |
| */ |
| BUILD_ASSERT_MSG(RESET_PIN > 16 && RESET_PIN < 24, |
| "Selected pin is not connected to nRF52840"); |
| |
| int bt_hci_transport_setup(struct device *h4) |
| { |
| int err; |
| char c; |
| struct device *port; |
| |
| port = device_get_binding(DT_GPIO_P0_DEV_NAME); |
| if (!port) { |
| return -EIO; |
| } |
| |
| /* Pull the pin low before configuring it as output, to ensure that |
| * it is driven to the correct level as soon as it is configured. |
| */ |
| err = gpio_pin_write(port, RESET_PIN, 0); |
| if (err) { |
| return err; |
| } |
| |
| err = gpio_pin_configure(port, RESET_PIN, GPIO_DIR_OUT); |
| if (err) { |
| return err; |
| } |
| |
| /* Reset the nRF52840 and let it wait until the pin is |
| * pulled low 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_write(port, RESET_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(1)); |
| |
| /* Drain bytes */ |
| while (uart_fifo_read(h4, &c, 1)) { |
| continue; |
| } |
| |
| /* We are ready, let the nRF52840 run to main */ |
| err = gpio_pin_write(port, RESET_PIN, 0); |
| if (err) { |
| return err; |
| } |
| |
| return 0; |
| } |
