static int pasemi_smb_xfer()

in busses/i2c-pasemi-core.c [165:313]

• 139 lines of code
• 27 McCabe index (conditional complexity)

static int pasemi_smb_xfer(struct i2c_adapter *adapter,
		u16 addr, unsigned short flags, char read_write, u8 command,
		int size, union i2c_smbus_data *data)
{
	struct pasemi_smbus *smbus = adapter->algo_data;
	unsigned int rd;
	int read_flag, err;
	int len = 0, i;

	/* All our ops take 8-bit shifted addresses */
	addr <<= 1;
	read_flag = read_write == I2C_SMBUS_READ;

	pasemi_smb_clear(smbus);

	switch (size) {
	case I2C_SMBUS_QUICK:
		TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START |
			  MTXFIFO_STOP);
		break;
	case I2C_SMBUS_BYTE:
		TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START);
		if (read_write)
			TXFIFO_WR(smbus, 1 | MTXFIFO_STOP | MTXFIFO_READ);
		else
			TXFIFO_WR(smbus, MTXFIFO_STOP | command);
		break;
	case I2C_SMBUS_BYTE_DATA:
		TXFIFO_WR(smbus, addr | MTXFIFO_START);
		TXFIFO_WR(smbus, command);
		if (read_write) {
			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
			TXFIFO_WR(smbus, 1 | MTXFIFO_READ | MTXFIFO_STOP);
		} else {
			TXFIFO_WR(smbus, MTXFIFO_STOP | data->byte);
		}
		break;
	case I2C_SMBUS_WORD_DATA:
		TXFIFO_WR(smbus, addr | MTXFIFO_START);
		TXFIFO_WR(smbus, command);
		if (read_write) {
			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
			TXFIFO_WR(smbus, 2 | MTXFIFO_READ | MTXFIFO_STOP);
		} else {
			TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
			TXFIFO_WR(smbus, MTXFIFO_STOP | (data->word >> 8));
		}
		break;
	case I2C_SMBUS_BLOCK_DATA:
		TXFIFO_WR(smbus, addr | MTXFIFO_START);
		TXFIFO_WR(smbus, command);
		if (read_write) {
			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
			TXFIFO_WR(smbus, 1 | MTXFIFO_READ);
			rd = RXFIFO_RD(smbus);
			len = min_t(u8, (rd & MRXFIFO_DATA_M),
				    I2C_SMBUS_BLOCK_MAX);
			TXFIFO_WR(smbus, len | MTXFIFO_READ |
					 MTXFIFO_STOP);
		} else {
			len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX);
			TXFIFO_WR(smbus, len);
			for (i = 1; i < len; i++)
				TXFIFO_WR(smbus, data->block[i]);
			TXFIFO_WR(smbus, data->block[len] | MTXFIFO_STOP);
		}
		break;
	case I2C_SMBUS_PROC_CALL:
		read_write = I2C_SMBUS_READ;
		TXFIFO_WR(smbus, addr | MTXFIFO_START);
		TXFIFO_WR(smbus, command);
		TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
		TXFIFO_WR(smbus, (data->word >> 8) & MTXFIFO_DATA_M);
		TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
		TXFIFO_WR(smbus, 2 | MTXFIFO_STOP | MTXFIFO_READ);
		break;
	case I2C_SMBUS_BLOCK_PROC_CALL:
		len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX - 1);
		read_write = I2C_SMBUS_READ;
		TXFIFO_WR(smbus, addr | MTXFIFO_START);
		TXFIFO_WR(smbus, command);
		TXFIFO_WR(smbus, len);
		for (i = 1; i <= len; i++)
			TXFIFO_WR(smbus, data->block[i]);
		TXFIFO_WR(smbus, addr | I2C_SMBUS_READ);
		TXFIFO_WR(smbus, MTXFIFO_READ | 1);
		rd = RXFIFO_RD(smbus);
		len = min_t(u8, (rd & MRXFIFO_DATA_M),
			    I2C_SMBUS_BLOCK_MAX - len);
		TXFIFO_WR(smbus, len | MTXFIFO_READ | MTXFIFO_STOP);
		break;

	default:
		dev_warn(&adapter->dev, "Unsupported transaction %d\n", size);
		return -EINVAL;
	}

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

	if (read_write == I2C_SMBUS_WRITE)
		return 0;

	switch (size) {
	case I2C_SMBUS_BYTE:
	case I2C_SMBUS_BYTE_DATA:
		rd = RXFIFO_RD(smbus);
		if (rd & MRXFIFO_EMPTY) {
			err = -ENODATA;
			goto reset_out;
		}
		data->byte = rd & MRXFIFO_DATA_M;
		break;
	case I2C_SMBUS_WORD_DATA:
	case I2C_SMBUS_PROC_CALL:
		rd = RXFIFO_RD(smbus);
		if (rd & MRXFIFO_EMPTY) {
			err = -ENODATA;
			goto reset_out;
		}
		data->word = rd & MRXFIFO_DATA_M;
		rd = RXFIFO_RD(smbus);
		if (rd & MRXFIFO_EMPTY) {
			err = -ENODATA;
			goto reset_out;
		}
		data->word |= (rd & MRXFIFO_DATA_M) << 8;
		break;
	case I2C_SMBUS_BLOCK_DATA:
	case I2C_SMBUS_BLOCK_PROC_CALL:
		data->block[0] = len;
		for (i = 1; i <= len; i ++) {
			rd = RXFIFO_RD(smbus);
			if (rd & MRXFIFO_EMPTY) {
				err = -ENODATA;
				goto reset_out;
			}
			data->block[i] = rd & MRXFIFO_DATA_M;
		}
		break;
	}

	return 0;

 reset_out:
	pasemi_reset(smbus);
	return err;
}