static ssize_t fec_mode_show()

in dfl-n3000-nios.c [238:284]

• 32 lines of code
• 11 McCabe index (conditional complexity)

static ssize_t fec_mode_show(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	unsigned int val, retimer_a_mode, retimer_b_mode, fec_modes;
	struct n3000_nios *nn = dev_get_drvdata(dev);
	int ret;

	/* FEC mode setting is not supported in early FW versions */
	ret = regmap_read(nn->regmap, N3000_NIOS_FW_VERSION, &val);
	if (ret)
		return ret;

	if (FIELD_GET(N3000_NIOS_FW_VERSION_MAJOR, val) < 3)
		return sysfs_emit(buf, "not supported\n");

	/* If no 25G links, FEC mode setting is not supported either */
	ret = get_retimer_mode(nn, N3000_NIOS_PKVL_A_MODE_STS, &retimer_a_mode);
	if (ret)
		return ret;

	ret = get_retimer_mode(nn, N3000_NIOS_PKVL_B_MODE_STS, &retimer_b_mode);
	if (ret)
		return ret;

	if (!IS_RETIMER_FEC_SUPPORTED(retimer_a_mode) &&
	    !IS_RETIMER_FEC_SUPPORTED(retimer_b_mode))
		return sysfs_emit(buf, "not supported\n");

	/* get the valid FEC mode for 25G links */
	ret = regmap_read(nn->regmap, N3000_NIOS_INIT, &val);
	if (ret)
		return ret;

	/*
	 * FEC mode should always be the same for all links, as we set them
	 * in this way.
	 */
	fec_modes = (val & N3000_NIOS_INIT_REQ_FEC_MODE_MSK_ALL);
	if (fec_modes == N3000_NIOS_INIT_REQ_FEC_MODE_NO_ALL)
		return sysfs_emit(buf, "no\n");
	else if (fec_modes == N3000_NIOS_INIT_REQ_FEC_MODE_KR_ALL)
		return sysfs_emit(buf, "kr\n");
	else if (fec_modes == N3000_NIOS_INIT_REQ_FEC_MODE_RS_ALL)
		return sysfs_emit(buf, "rs\n");

	return -EFAULT;
}