static ssize_t output_store()

in slaves/w1_ds2405.c [137:196]

• 42 lines of code
• 10 McCabe index (conditional complexity)

static ssize_t output_store(struct device *device,
			    struct device_attribute *attr,
			    const char *buf, size_t count)
{
	struct w1_slave *sl = dev_to_w1_slave(device);
	struct w1_master *dev = sl->master;

	int ret, current_pio;
	unsigned int val;
	ssize_t f_retval;

	if (count < 1)
		return -EINVAL;

	if (sscanf(buf, " %u%n", &val, &ret) < 1)
		return -EINVAL;

	if (val != 0 && val != 1)
		return -EINVAL;

	f_retval = ret;

	ret = mutex_lock_interruptible(&dev->bus_mutex);
	if (ret)
		return ret;

	current_pio = w1_ds2405_read_pio(sl);
	if (current_pio < 0) {
		f_retval = current_pio;
		goto out_unlock;
	}

	if (current_pio == val)
		goto out_unlock;

	if (w1_reset_bus(dev) != 0) {
		f_retval = -ENODEV;
		goto out_unlock;
	}

	/*
	 * can't use w1_reset_select_slave() here since it uses Skip ROM if
	 * there is only one device on bus
	 */
	do {
		u64 dev_addr = le64_to_cpu(*(u64 *)&sl->reg_num);
		u8 cmd[9];

		cmd[0] = W1_MATCH_ROM;
		memcpy(&cmd[1], &dev_addr, sizeof(dev_addr));

		w1_write_block(dev, cmd, sizeof(cmd));
	} while (0);

out_unlock:
	w1_reset_bus(dev);
	mutex_unlock(&dev->bus_mutex);

	return f_retval;
}