int __iio_device_attr_init()

in industrialio-core.c [1003:1130]

• 120 lines of code
• 21 McCabe index (conditional complexity)

int __iio_device_attr_init(struct device_attribute *dev_attr,
			   const char *postfix,
			   struct iio_chan_spec const *chan,
			   ssize_t (*readfunc)(struct device *dev,
					       struct device_attribute *attr,
					       char *buf),
			   ssize_t (*writefunc)(struct device *dev,
						struct device_attribute *attr,
						const char *buf,
						size_t len),
			   enum iio_shared_by shared_by)
{
	int ret = 0;
	char *name = NULL;
	char *full_postfix;
	sysfs_attr_init(&dev_attr->attr);

	/* Build up postfix of <extend_name>_<modifier>_postfix */
	if (chan->modified && (shared_by == IIO_SEPARATE)) {
		if (chan->extend_name)
			full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
						 iio_modifier_names[chan
								    ->channel2],
						 chan->extend_name,
						 postfix);
		else
			full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
						 iio_modifier_names[chan
								    ->channel2],
						 postfix);
	} else {
		if (chan->extend_name == NULL || shared_by != IIO_SEPARATE)
			full_postfix = kstrdup(postfix, GFP_KERNEL);
		else
			full_postfix = kasprintf(GFP_KERNEL,
						 "%s_%s",
						 chan->extend_name,
						 postfix);
	}
	if (full_postfix == NULL)
		return -ENOMEM;

	if (chan->differential) { /* Differential can not have modifier */
		switch (shared_by) {
		case IIO_SHARED_BY_ALL:
			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
			break;
		case IIO_SHARED_BY_DIR:
			name = kasprintf(GFP_KERNEL, "%s_%s",
						iio_direction[chan->output],
						full_postfix);
			break;
		case IIO_SHARED_BY_TYPE:
			name = kasprintf(GFP_KERNEL, "%s_%s-%s_%s",
					    iio_direction[chan->output],
					    iio_chan_type_name_spec[chan->type],
					    iio_chan_type_name_spec[chan->type],
					    full_postfix);
			break;
		case IIO_SEPARATE:
			if (!chan->indexed) {
				WARN(1, "Differential channels must be indexed\n");
				ret = -EINVAL;
				goto error_free_full_postfix;
			}
			name = kasprintf(GFP_KERNEL,
					    "%s_%s%d-%s%d_%s",
					    iio_direction[chan->output],
					    iio_chan_type_name_spec[chan->type],
					    chan->channel,
					    iio_chan_type_name_spec[chan->type],
					    chan->channel2,
					    full_postfix);
			break;
		}
	} else { /* Single ended */
		switch (shared_by) {
		case IIO_SHARED_BY_ALL:
			name = kasprintf(GFP_KERNEL, "%s", full_postfix);
			break;
		case IIO_SHARED_BY_DIR:
			name = kasprintf(GFP_KERNEL, "%s_%s",
						iio_direction[chan->output],
						full_postfix);
			break;
		case IIO_SHARED_BY_TYPE:
			name = kasprintf(GFP_KERNEL, "%s_%s_%s",
					    iio_direction[chan->output],
					    iio_chan_type_name_spec[chan->type],
					    full_postfix);
			break;

		case IIO_SEPARATE:
			if (chan->indexed)
				name = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
						    iio_direction[chan->output],
						    iio_chan_type_name_spec[chan->type],
						    chan->channel,
						    full_postfix);
			else
				name = kasprintf(GFP_KERNEL, "%s_%s_%s",
						    iio_direction[chan->output],
						    iio_chan_type_name_spec[chan->type],
						    full_postfix);
			break;
		}
	}
	if (name == NULL) {
		ret = -ENOMEM;
		goto error_free_full_postfix;
	}
	dev_attr->attr.name = name;

	if (readfunc) {
		dev_attr->attr.mode |= S_IRUGO;
		dev_attr->show = readfunc;
	}

	if (writefunc) {
		dev_attr->attr.mode |= S_IWUSR;
		dev_attr->store = writefunc;
	}

error_free_full_postfix:
	kfree(full_postfix);

	return ret;
}