drivers/media/pci/cobalt/cobalt-alsa-main.c

Source file repositories/reference/linux-study-clean/drivers/media/pci/cobalt/cobalt-alsa-main.c

File Facts

System
Linux kernel
Corpus path
drivers/media/pci/cobalt/cobalt-alsa-main.c
Extension
.c
Size
3444 bytes
Lines
151
Domain
Driver Families
Bucket
drivers/media
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-only
/*
 *  ALSA interface to cobalt PCM capture streams
 *
 *  Copyright 2014-2015 Cisco Systems, Inc. and/or its affiliates.
 *  All rights reserved.
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/spinlock.h>

#include <media/v4l2-device.h>

#include <sound/core.h>
#include <sound/initval.h>

#include "cobalt-driver.h"
#include "cobalt-alsa.h"
#include "cobalt-alsa-pcm.h"

static void snd_cobalt_card_free(struct snd_cobalt_card *cobsc)
{
	if (cobsc == NULL)
		return;

	cobsc->s->alsa = NULL;

	kfree(cobsc);
}

static void snd_cobalt_card_private_free(struct snd_card *sc)
{
	if (sc == NULL)
		return;
	snd_cobalt_card_free(sc->private_data);
	sc->private_data = NULL;
	sc->private_free = NULL;
}

static int snd_cobalt_card_create(struct cobalt_stream *s,
				       struct snd_card *sc,
				       struct snd_cobalt_card **cobsc)
{
	*cobsc = kzalloc_obj(struct snd_cobalt_card);
	if (*cobsc == NULL)
		return -ENOMEM;

	(*cobsc)->s = s;
	(*cobsc)->sc = sc;

	sc->private_data = *cobsc;
	sc->private_free = snd_cobalt_card_private_free;

	return 0;
}

static int snd_cobalt_card_set_names(struct snd_cobalt_card *cobsc)
{
	struct cobalt_stream *s = cobsc->s;
	struct cobalt *cobalt = s->cobalt;
	struct snd_card *sc = cobsc->sc;

	/* sc->driver is used by alsa-lib's configurator: simple, unique */
	strscpy(sc->driver, "cobalt", sizeof(sc->driver));

	/* sc->shortname is a symlink in /proc/asound: COBALT-M -> cardN */
	snprintf(sc->shortname,  sizeof(sc->shortname), "cobalt-%d-%d",
		 cobalt->instance, s->video_channel);

	/* sc->longname is read from /proc/asound/cards */
	snprintf(sc->longname, sizeof(sc->longname),
		 "Cobalt %d HDMI %d",
		 cobalt->instance, s->video_channel);

	return 0;
}

int cobalt_alsa_init(struct cobalt_stream *s)
{
	struct cobalt *cobalt = s->cobalt;
	struct snd_card *sc = NULL;
	struct snd_cobalt_card *cobsc;
	int ret;

	/* Numbrs steps from "Writing an ALSA Driver" by Takashi Iwai */

Annotation

Implementation Notes