static int w1_f2d_write()

in slaves/w1_ds2431.c [145:201]

• 36 lines of code
• 9 McCabe index (conditional complexity)

static int w1_f2d_write(struct w1_slave *sl, int addr, int len, const u8 *data)
{
	int tries = W1_F2D_READ_RETRIES;
	u8 wrbuf[4];
	u8 rdbuf[W1_F2D_SCRATCH_SIZE + 3];
	u8 es = (addr + len - 1) % W1_F2D_SCRATCH_SIZE;

retry:

	/* Write the data to the scratchpad */
	if (w1_reset_select_slave(sl))
		return -1;

	wrbuf[0] = W1_F2D_WRITE_SCRATCH;
	wrbuf[1] = addr & 0xff;
	wrbuf[2] = addr >> 8;

	w1_write_block(sl->master, wrbuf, 3);
	w1_write_block(sl->master, data, len);

	/* Read the scratchpad and verify */
	if (w1_reset_select_slave(sl))
		return -1;

	w1_write_8(sl->master, W1_F2D_READ_SCRATCH);
	w1_read_block(sl->master, rdbuf, len + 3);

	/* Compare what was read against the data written */
	if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
	    (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) {

		if (--tries)
			goto retry;

		dev_err(&sl->dev,
			"could not write to eeprom, scratchpad compare failed %d times\n",
			W1_F2D_READ_RETRIES);

		return -1;
	}

	/* Copy the scratchpad to EEPROM */
	if (w1_reset_select_slave(sl))
		return -1;

	wrbuf[0] = W1_F2D_COPY_SCRATCH;
	wrbuf[3] = es;
	w1_write_block(sl->master, wrbuf, 4);

	/* Sleep for tprog ms to wait for the write to complete */
	msleep(W1_F2D_TPROG_MS);

	/* Reset the bus to wake up the EEPROM  */
	w1_reset_bus(sl->master);

	return 0;
}