sound/usb/caiaq/midi.c

Source file repositories/reference/linux-study-clean/sound/usb/caiaq/midi.c

File Facts

System
Linux kernel
Corpus path
sound/usb/caiaq/midi.c
Extension
.c
Size
3849 bytes
Lines
163
Domain
Driver Families
Bucket
sound/usb
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Copyright (c) 2006,2007 Daniel Mack
*/

#include <linux/device.h>
#include <linux/usb.h>
#include <linux/gfp.h>
#include <sound/rawmidi.h>
#include <sound/core.h>
#include <sound/pcm.h>

#include "device.h"
#include "midi.h"

static int snd_usb_caiaq_midi_input_open(struct snd_rawmidi_substream *substream)
{
	return 0;
}

static int snd_usb_caiaq_midi_input_close(struct snd_rawmidi_substream *substream)
{
	return 0;
}

static void snd_usb_caiaq_midi_input_trigger(struct snd_rawmidi_substream *substream, int up)
{
	struct snd_usb_caiaqdev *cdev = substream->rmidi->private_data;

	if (!cdev)
		return;

	cdev->midi_receive_substream = up ? substream : NULL;
}


static int snd_usb_caiaq_midi_output_open(struct snd_rawmidi_substream *substream)
{
	return 0;
}

static int snd_usb_caiaq_midi_output_close(struct snd_rawmidi_substream *substream)
{
	struct snd_usb_caiaqdev *cdev = substream->rmidi->private_data;
	if (cdev->midi_out_active) {
		usb_kill_urb(&cdev->midi_out_urb);
		cdev->midi_out_active = 0;
	}
	return 0;
}

static void snd_usb_caiaq_midi_send(struct snd_usb_caiaqdev *cdev,
				    struct snd_rawmidi_substream *substream)
{
	int len, ret;
	struct device *dev = caiaqdev_to_dev(cdev);

	cdev->midi_out_buf[0] = EP1_CMD_MIDI_WRITE;
	cdev->midi_out_buf[1] = 0; /* port */
	len = snd_rawmidi_transmit(substream, cdev->midi_out_buf + 3,
				   EP1_BUFSIZE - 3);

	if (len <= 0)
		return;

	cdev->midi_out_buf[2] = len;
	cdev->midi_out_urb.transfer_buffer_length = len+3;

	ret = usb_submit_urb(&cdev->midi_out_urb, GFP_ATOMIC);
	if (ret < 0)
		dev_err(dev,
			"snd_usb_caiaq_midi_send(%p): usb_submit_urb() failed,"
			"ret=%d, len=%d\n", substream, ret, len);
	else
		cdev->midi_out_active = 1;
}

static void snd_usb_caiaq_midi_output_trigger(struct snd_rawmidi_substream *substream, int up)
{
	struct snd_usb_caiaqdev *cdev = substream->rmidi->private_data;

	if (up) {
		cdev->midi_out_substream = substream;
		if (!cdev->midi_out_active)
			snd_usb_caiaq_midi_send(cdev, substream);
	} else {
		cdev->midi_out_substream = NULL;
	}
}

Annotation

Implementation Notes