drivers/i2c/busses/i2c-usbio.c

Source file repositories/reference/linux-study-clean/drivers/i2c/busses/i2c-usbio.c

File Facts

System
Linux kernel
Corpus path
drivers/i2c/busses/i2c-usbio.c
Extension
.c
Size
7997 bytes
Lines
323
Domain
Driver Families
Bucket
drivers/i2c
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 usbio_i2c {
	struct i2c_adapter adap;
	struct auxiliary_device *adev;
	struct usbio_i2c_rw *rwbuf;
	unsigned long quirks;
	u32 speed;
	u16 txbuf_len;
	u16 rxbuf_len;
};

static const struct acpi_device_id usbio_i2c_acpi_hids[] = {
	{ "INTC1008" }, /* MTL */
	{ "INTC10B3" }, /* ARL */
	{ "INTC10B6" }, /* LNL */
	{ "INTC10D2" }, /* MTL-CVF */
	{ "INTC10E3" }, /* PTL */
	{ "INTC1118" }, /* NVL */
	{ }
};

static const u32 usbio_i2c_speeds[] = {
	I2C_MAX_STANDARD_MODE_FREQ,
	I2C_MAX_FAST_MODE_FREQ,
	I2C_MAX_FAST_MODE_PLUS_FREQ,
	I2C_MAX_HIGH_SPEED_MODE_FREQ
};

static void usbio_i2c_uninit(struct i2c_adapter *adap, struct i2c_msg *msg)
{
	struct usbio_i2c *i2c = i2c_get_adapdata(adap);
	struct usbio_i2c_uninit ubuf;

	ubuf.busid = i2c->adev->id;
	ubuf.config = cpu_to_le16(msg->addr);

	usbio_bulk_msg(i2c->adev, USBIO_PKTTYPE_I2C, USBIO_I2CCMD_UNINIT, true,
		       &ubuf, sizeof(ubuf), NULL, 0);
}

static int usbio_i2c_init(struct i2c_adapter *adap, struct i2c_msg *msg)
{
	struct usbio_i2c *i2c = i2c_get_adapdata(adap);
	struct usbio_i2c_init ibuf;
	void *reply_buf;
	u16 reply_len;
	int ret;

	ibuf.busid = i2c->adev->id;
	ibuf.config = cpu_to_le16(msg->addr);
	ibuf.speed = cpu_to_le32(i2c->speed);

	if (i2c->quirks & USBIO_QUIRK_I2C_NO_INIT_ACK) {
		reply_buf = NULL;
		reply_len = 0;
	} else {
		reply_buf = &ibuf;
		reply_len = sizeof(ibuf);
	}

	ret = usbio_bulk_msg(i2c->adev, USBIO_PKTTYPE_I2C, USBIO_I2CCMD_INIT, true,
			     &ibuf, sizeof(ibuf), reply_buf, reply_len);
	if (ret != sizeof(ibuf))
		return (ret < 0) ? ret : -EIO;

	return 0;
}

static int usbio_i2c_read(struct i2c_adapter *adap, struct i2c_msg *msg)
{
	struct usbio_i2c *i2c = i2c_get_adapdata(adap);
	u16 rxchunk = i2c->rxbuf_len - I2C_RW_OVERHEAD;
	struct usbio_i2c_rw *rbuf = i2c->rwbuf;
	int ret;

	rbuf->busid = i2c->adev->id;
	rbuf->config = cpu_to_le16(msg->addr);
	rbuf->size = cpu_to_le16(msg->len);

	if (msg->len > rxchunk) {
		/* Need to split the input buffer */
		u16 len = 0;

		do {
			if (msg->len - len < rxchunk)
				rxchunk = msg->len - len;

			ret = usbio_bulk_msg(i2c->adev, USBIO_PKTTYPE_I2C,
					     USBIO_I2CCMD_READ, true,
					     rbuf, len == 0 ? sizeof(*rbuf) : 0,
					     rbuf, sizeof(*rbuf) + rxchunk);

Annotation

Implementation Notes