zmk/app/src/usb_hid.c

/*
 * Copyright (c) 2020 The ZMK Contributors
 *
 * SPDX-License-Identifier: MIT
 */

#include <device.h>
#include <init.h>

#include <usb/usb_device.h>
#include <usb/class/usb_hid.h>

#include <zmk/usb.h>
#include <zmk/hid.h>
#include <zmk/keymap.h>
#include <zmk/led_indicators.h>
#include <zmk/event_manager.h>

LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);

static const struct device *hid_dev;

static K_SEM_DEFINE(hid_sem, 1, 1);

static void in_ready_cb(const struct device *dev) { k_sem_give(&hid_sem); }

#define HID_GET_REPORT_TYPE_MASK 0xff00
#define HID_GET_REPORT_ID_MASK 0x00ff

#define HID_REPORT_TYPE_INPUT 0x100
#define HID_REPORT_TYPE_OUTPUT 0x200
#define HID_REPORT_TYPE_FEATURE 0x300

#if IS_ENABLED(CONFIG_ZMK_USB_BOOT)
static uint8_t hid_protocol = HID_PROTOCOL_REPORT;

static void set_proto_cb(const struct device *dev, uint8_t protocol) { hid_protocol = protocol; }

void zmk_usb_hid_set_protocol(uint8_t protocol) { hid_protocol = protocol; }
#endif /* IS_ENABLED(CONFIG_ZMK_USB_BOOT) */

static uint8_t *get_keyboard_report(size_t *len) {
    if (hid_protocol == HID_PROTOCOL_REPORT) {
        struct zmk_hid_keyboard_report *report = zmk_hid_get_keyboard_report();
        *len = sizeof(*report);
        return (uint8_t *)report;
    }
#if IS_ENABLED(CONFIG_ZMK_USB_BOOT)
    zmk_hid_boot_report_t *boot_report = zmk_hid_get_boot_report();
    *len = sizeof(*boot_report);
    return (uint8_t *)boot_report;
#endif
}

static int get_report_cb(const struct device *dev, struct usb_setup_packet *setup, int32_t *len,
                         uint8_t **data) {

    /*
     * 7.2.1 of the HID v1.11 spec is unclear about handling requests for reports that do not exist
     * For requested reports that aren't input reports, return -ENOTSUP like the Zephyr subsys does
     */
    if ((setup->wValue & HID_GET_REPORT_TYPE_MASK) != HID_REPORT_TYPE_INPUT) {
        LOG_ERR("Unsupported report type %d requested", (setup->wValue & HID_GET_REPORT_TYPE_MASK)
                                                            << 8);
        return -ENOTSUP;
    }

    switch (setup->wValue & HID_GET_REPORT_ID_MASK) {
    case HID_REPORT_ID_KEYBOARD: {
        *data = get_keyboard_report(len);
        break;
    }
    case HID_REPORT_ID_CONSUMER: {
        struct zmk_hid_consumer_report *report = zmk_hid_get_consumer_report();
        *data = (uint8_t *)report;
        *len = sizeof(*report);
        break;
    }
    default:
        LOG_ERR("Invalid report ID %d requested", setup->wValue & HID_GET_REPORT_ID_MASK);
        return -EINVAL;
    }

    return 0;
}

static int set_report_cb(const struct device *dev, struct usb_setup_packet *setup, int32_t *len,
                         uint8_t **data) {
    if ((setup->wValue & HID_GET_REPORT_TYPE_MASK) != HID_REPORT_TYPE_OUTPUT) {
        LOG_ERR("Unsupported report type %d requested",
                (setup->wValue & HID_GET_REPORT_TYPE_MASK) >> 8);
        return -ENOTSUP;
    }

    switch (setup->wValue & HID_GET_REPORT_ID_MASK) {
    case HID_REPORT_ID_LEDS:
        if (*len != sizeof(struct zmk_hid_led_report)) {
            LOG_ERR("LED set report is malformed: length=%d", *len);
        } else {
            struct zmk_hid_led_report *report = (struct zmk_hid_led_report *)*data;
            zmk_leds_process_report(&report->body, ZMK_ENDPOINT_USB, 0);
        }
        break;
    default:
        LOG_ERR("Invalid report ID %d requested", setup->wValue & HID_GET_REPORT_ID_MASK);
        return -EINVAL;
    }

    return 0;
}

static const struct hid_ops ops = {
#if IS_ENABLED(CONFIG_ZMK_USB_BOOT)
    .protocol_change = set_proto_cb,
#endif
    .int_in_ready = in_ready_cb,
    .get_report = get_report_cb,
    .set_report = set_report_cb,
};

static int zmk_usb_hid_send_report(const uint8_t *report, size_t len) {
    switch (zmk_usb_get_status()) {
    case USB_DC_SUSPEND:
        return usb_wakeup_request();
    case USB_DC_ERROR:
    case USB_DC_RESET:
    case USB_DC_DISCONNECTED:
    case USB_DC_UNKNOWN:
        return -ENODEV;
    default:
        k_sem_take(&hid_sem, K_MSEC(30));
        int err = hid_int_ep_write(hid_dev, report, len, NULL);

        if (err) {
            k_sem_give(&hid_sem);
        }

        return err;
    }
}

int zmk_usb_hid_send_keyboard_report() {
    size_t len;
    uint8_t *report = get_keyboard_report(&len);
    return zmk_usb_hid_send_report(report, len);
}

int zmk_usb_hid_send_consumer_report() {
#if IS_ENABLED(CONFIG_ZMK_USB_BOOT)
    if (hid_protocol == HID_PROTOCOL_BOOT) {
        return -ENOTSUP;
    }
#endif /* IS_ENABLED(CONFIG_ZMK_USB_BOOT) */

    struct zmk_hid_consumer_report *report = zmk_hid_get_consumer_report();
    return zmk_usb_hid_send_report((uint8_t *)report, sizeof(*report));
}

static int zmk_usb_hid_init(const struct device *_arg) {
    hid_dev = device_get_binding("HID_0");
    if (hid_dev == NULL) {
        LOG_ERR("Unable to locate HID device");
        return -EINVAL;
    }

    usb_hid_register_device(hid_dev, zmk_hid_report_desc, sizeof(zmk_hid_report_desc), &ops);
    usb_hid_init(hid_dev);

    return 0;
}

SYS_INIT(zmk_usb_hid_init, APPLICATION, CONFIG_APPLICATION_INIT_PRIORITY);