drivers/media/i2c/ov7640.c

Source file repositories/reference/linux-study-clean/drivers/media/i2c/ov7640.c

File Facts

System
Linux kernel
Corpus path
drivers/media/i2c/ov7640.c
Extension
.c
Size
1953 bytes
Lines
94
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

struct reg_val {
	u8 reg;
	u8 val;
};

static const struct reg_val regval_init[] = {
	{0x12, 0x80},
	{0x12, 0x54},
	{0x14, 0x24},
	{0x15, 0x01},
	{0x28, 0x20},
	{0x75, 0x82},
};

static int write_regs(struct i2c_client *client,
		const struct reg_val *rv, int len)
{
	while (--len >= 0) {
		if (i2c_smbus_write_byte_data(client, rv->reg, rv->val) < 0)
			return -1;
		rv++;
	}
	return 0;
}

/* ----------------------------------------------------------------------- */

static const struct v4l2_subdev_ops ov7640_ops;

static int ov7640_probe(struct i2c_client *client)
{
	struct i2c_adapter *adapter = client->adapter;
	struct v4l2_subdev *sd;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
		return -ENODEV;

	sd = devm_kzalloc(&client->dev, sizeof(*sd), GFP_KERNEL);
	if (sd == NULL)
		return -ENOMEM;
	v4l2_i2c_subdev_init(sd, client, &ov7640_ops);

	client->flags = I2C_CLIENT_SCCB;

	v4l_info(client, "chip found @ 0x%02x (%s)\n",
			client->addr << 1, client->adapter->name);

	if (write_regs(client, regval_init, ARRAY_SIZE(regval_init)) < 0) {
		v4l_err(client, "error initializing OV7640\n");
		return -ENODEV;
	}

	return 0;
}


static void ov7640_remove(struct i2c_client *client)
{
	struct v4l2_subdev *sd = i2c_get_clientdata(client);

	v4l2_device_unregister_subdev(sd);
}

static const struct i2c_device_id ov7640_id[] = {
	{ .name = "ov7640" },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ov7640_id);

static struct i2c_driver ov7640_driver = {
	.driver = {
		.name	= "ov7640",
	},
	.probe = ov7640_probe,
	.remove = ov7640_remove,
	.id_table = ov7640_id,
};
module_i2c_driver(ov7640_driver);

Annotation

Implementation Notes