sound/ppc/keywest.c

Source file repositories/reference/linux-study-clean/sound/ppc/keywest.c

File Facts

System
Linux kernel
Corpus path
sound/ppc/keywest.c
Extension
.c
Size
3453 bytes
Lines
156
Domain
Driver Families
Bucket
sound/ppc
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
/*
 * common keywest i2c layer
 *
 * Copyright (c) by Takashi Iwai <tiwai@suse.de>
 */


#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <sound/core.h>
#include "pmac.h"

static struct pmac_keywest *keywest_ctx;
static bool keywest_probed;

static int keywest_probe(struct i2c_client *client)
{
	keywest_probed = true;
	/* If instantiated via i2c-powermac, we still need to set the client */
	if (!keywest_ctx->client)
		keywest_ctx->client = client;
	i2c_set_clientdata(client, keywest_ctx);
	return 0;
}

/*
 * This is kind of a hack, best would be to turn powermac to fixed i2c
 * bus numbers and declare the sound device as part of platform
 * initialization
 */
static int keywest_attach_adapter(struct i2c_adapter *adapter)
{
	struct i2c_board_info info;
	struct i2c_client *client;

	if (! keywest_ctx)
		return -EINVAL;

	if (strncmp(adapter->name, "mac-io", 6))
		return -EINVAL; /* ignored */

	memset(&info, 0, sizeof(struct i2c_board_info));
	strscpy(info.type, "keywest", I2C_NAME_SIZE);
	info.addr = keywest_ctx->addr;
	client = i2c_new_client_device(adapter, &info);
	if (IS_ERR(client))
		return PTR_ERR(client);
	keywest_ctx->client = client;

	/*
	 * We know the driver is already loaded, so the device should be
	 * already bound. If not it means binding failed, and then there
	 * is no point in keeping the device instantiated.
	 */
	if (!keywest_ctx->client->dev.driver) {
		i2c_unregister_device(keywest_ctx->client);
		keywest_ctx->client = NULL;
		return -ENODEV;
	}
	
	return 0;
}

static void keywest_remove(struct i2c_client *client)
{
	if (! keywest_ctx)
		return;
	if (client == keywest_ctx->client)
		keywest_ctx->client = NULL;
}


static const struct i2c_device_id keywest_i2c_id[] = {
	{ "MAC,tas3004" },	/* instantiated by i2c-powermac */
	{ "keywest" },		/* instantiated by us if needed */
	{ }
};
MODULE_DEVICE_TABLE(i2c, keywest_i2c_id);

static struct i2c_driver keywest_driver = {
	.driver = {
		.name = "PMac Keywest Audio",
	},
	.probe = keywest_probe,
	.remove = keywest_remove,
	.id_table = keywest_i2c_id,
};

Annotation

Implementation Notes