int bbc_i2c_readb()

in char/bbc_i2c.c [181:228]

• 34 lines of code
• 8 McCabe index (conditional complexity)

int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off)
{
	struct bbc_i2c_bus *bp = client->bp;
	unsigned char address = client->address, status;
	int ret = -1;

	if (bp->i2c_bussel_reg != NULL)
		writeb(client->bus, bp->i2c_bussel_reg);

	writeb(address, bp->i2c_control_regs + 0x1);
	writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
	if (wait_for_pin(bp, &status))
		goto out;

	writeb(off, bp->i2c_control_regs + 0x1);
	if (wait_for_pin(bp, &status) ||
	    (status & I2C_PCF_LRB) != 0)
		goto out;

	writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);

	address |= 0x1; /* READ */

	writeb(address, bp->i2c_control_regs + 0x1);
	writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
	if (wait_for_pin(bp, &status))
		goto out;

	/* Set PIN back to one so the device sends the first
	 * byte.
	 */
	(void) readb(bp->i2c_control_regs + 0x1);
	if (wait_for_pin(bp, &status))
		goto out;

	writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
	*byte = readb(bp->i2c_control_regs + 0x1);
	if (wait_for_pin(bp, &status))
		goto out;

	ret = 0;

out:
	writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
	(void) readb(bp->i2c_control_regs + 0x1);

	return ret;
}