drivers/i2c/busses/i2c-pasemi-core.c

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

File Facts

System
Linux kernel
Corpus path
drivers/i2c/busses/i2c-pasemi-core.c
Extension
.c
Size
11568 bytes
Lines
466
Domain
Driver Families
Bucket
drivers/i2c
Inferred role
Driver Families: exported/initcall integration point
Status
integration 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

if (ret < 0) {
			dev_err(smbus->dev,
				"Completion wait failed with %d, status 0x%08x\n",
				ret, status);
			return ret;
		} else if (ret == 0) {
			dev_err(smbus->dev, "Timeout, status 0x%08x\n", status);
			return -ETIME;
		}
	} else {
		int ret = readx_poll_timeout(
				ioread32, smbus->ioaddr + REG_SMSTA,
				status, status & SMSTA_XEN,
				USEC_PER_MSEC,
				USEC_PER_MSEC * PASEMI_TRANSFER_TIMEOUT_MS);

		if (ret < 0) {
			dev_err(smbus->dev, "Timeout, status 0x%08x\n", status);
			return -ETIME;
		}
	}

	/* Controller timeout? */
	if (status & SMSTA_TOM) {
		dev_err(smbus->dev, "Controller timeout, status 0x%08x\n", status);
		return -EIO;
	}

	/* Peripheral timeout? */
	if (status & SMSTA_MTO) {
		dev_err(smbus->dev, "Peripheral timeout, status 0x%08x\n", status);
		return -ETIME;
	}

	/* Still stuck in a transaction? */
	if (status & SMSTA_XIP) {
		dev_err(smbus->dev, "Bus stuck, status 0x%08x\n", status);
		return -EIO;
	}

	/* Arbitration loss? */
	if (status & SMSTA_MTA) {
		dev_err(smbus->dev, "Arbitration loss, status 0x%08x\n", status);
		return -EBUSY;
	}

	/* Got NACK? */
	if (status & SMSTA_MTN) {
		dev_err(smbus->dev, "NACK, status 0x%08x\n", status);
		return -ENXIO;
	}

	/* Clear XEN */
	reg_write(smbus, REG_SMSTA, SMSTA_XEN);

	return 0;
}

static int pasemi_i2c_xfer_msg(struct i2c_adapter *adapter,
			       struct i2c_msg *msg, int stop)
{
	struct pasemi_smbus *smbus = adapter->algo_data;
	int read, i, err;
	u32 rd;

	read = msg->flags & I2C_M_RD ? 1 : 0;

	TXFIFO_WR(smbus, MTXFIFO_START | i2c_8bit_addr_from_msg(msg));

	if (read) {
		TXFIFO_WR(smbus, msg->len | MTXFIFO_READ |
				 (stop ? MTXFIFO_STOP : 0));

		err = pasemi_smb_waitready(smbus);
		if (err)
			goto reset_out;

		for (i = 0; i < msg->len; i++) {
			rd = RXFIFO_RD(smbus);
			if (rd & MRXFIFO_EMPTY) {
				err = -ENODATA;
				goto reset_out;
			}
			msg->buf[i] = rd & MRXFIFO_DATA_M;
		}
	} else {
		for (i = 0; i < msg->len - 1; i++)
			TXFIFO_WR(smbus, msg->buf[i]);

		TXFIFO_WR(smbus, msg->buf[msg->len-1] |

Annotation

Implementation Notes