os_hid.h

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// Copyright 2019, Collabora, Ltd.
// SPDX-License-Identifier: BSL-1.0
/*!
 * @file
 * @brief  Wrapper around OS native hid functions.
 * @author Jakob Bornecrantz <jakob@collabora.com>
 * @author Ryan Pavlik <ryan.pavlik@collabora.com>
 *
 * @ingroup aux_os
 */

#pragma once

#include "xrt/xrt_config_os.h"
#include <stdint.h>
#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif


/*!
 * Representing a single hid interface on a device.
 */
struct os_hid_device
{
        int (*read)(struct os_hid_device *hid_dev,
                    uint8_t *data,
                    size_t size,
                    int milliseconds);

        int (*write)(struct os_hid_device *hid_dev,
                     const uint8_t *data,
                     size_t size);

        int (*get_feature)(struct os_hid_device *hid_dev,
                           uint8_t report_num,
                           uint8_t *data,
                           size_t size);

        int (*get_feature_timeout)(struct os_hid_device *hid_dev,
                                   void *data,
                                   size_t size,
                                   uint32_t timeout);

        int (*set_feature)(struct os_hid_device *hid_dev,
                           const uint8_t *data,
                           size_t size);

        void (*destroy)(struct os_hid_device *hid_dev);
};

/*!
 * Read the next input report, if any, from the given hid device.
 *
 * If milliseconds are negative, this call blocks indefinitely, 0 polls,
 * and positive will block for that amount of milliseconds.
 */
static inline int
os_hid_read(struct os_hid_device *hid_dev,
            uint8_t *data,
            size_t size,
            int milliseconds)
{
        return hid_dev->read(hid_dev, data, size, milliseconds);
}

/*!
 * Write an output report to the given device.
 */
static inline int
os_hid_write(struct os_hid_device *hid_dev, const uint8_t *data, size_t size)
{
        return hid_dev->write(hid_dev, data, size);
}

/*!
 * Get a numbered feature report.
 *
 * If the device doesn't have more than one feature report, just request
 * report 0.
 */
static inline int
os_hid_get_feature(struct os_hid_device *hid_dev,
                   uint8_t report_num,
                   uint8_t *data,
                   size_t size)
{
        return hid_dev->get_feature(hid_dev, report_num, data, size);
}

/*!
 * Get a feature report with a timeout.
 */
static inline int
os_hid_get_feature_timeout(struct os_hid_device *hid_dev,
                           void *data,
                           size_t size,
                           uint32_t timeout)
{
        return hid_dev->get_feature_timeout(hid_dev, data, size, timeout);
}

/*!
 * Set a feature report.
 *
 * The first byte of the buffer is the report number, to be followed by
 * the data of the report.
 */
static inline int
os_hid_set_feature(struct os_hid_device *hid_dev,
                   const uint8_t *data,
                   size_t size)
{
        return hid_dev->set_feature(hid_dev, data, size);
}

/*!
 * Close and free the given device.
 */
static inline void
os_hid_destroy(struct os_hid_device *hid_dev)
{
        hid_dev->destroy(hid_dev);
}

#ifdef XRT_OS_LINUX
/*!
 * Open the given path as a hidraw device.
 */
int
os_hid_open_hidraw(const char *path, struct os_hid_device **out_hid);
#endif

#ifdef __cplusplus
} // extern "C"
#endif