int i2c_mux_add_adapter()

in i2c-mux.c [282:437]

• 122 lines of code
• 26 McCabe index (conditional complexity)

int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
			u32 force_nr, u32 chan_id,
			unsigned int class)
{
	struct i2c_adapter *parent = muxc->parent;
	struct i2c_mux_priv *priv;
	char symlink_name[20];
	int ret;

	if (muxc->num_adapters >= muxc->max_adapters) {
		dev_err(muxc->dev, "No room for more i2c-mux adapters\n");
		return -EINVAL;
	}

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	/* Set up private adapter data */
	priv->muxc = muxc;
	priv->chan_id = chan_id;

	/* Need to do algo dynamically because we don't know ahead
	 * of time what sort of physical adapter we'll be dealing with.
	 */
	if (parent->algo->master_xfer) {
		if (muxc->mux_locked)
			priv->algo.master_xfer = i2c_mux_master_xfer;
		else
			priv->algo.master_xfer = __i2c_mux_master_xfer;
	}
	if (parent->algo->master_xfer_atomic)
		priv->algo.master_xfer_atomic = priv->algo.master_xfer;

	if (parent->algo->smbus_xfer) {
		if (muxc->mux_locked)
			priv->algo.smbus_xfer = i2c_mux_smbus_xfer;
		else
			priv->algo.smbus_xfer = __i2c_mux_smbus_xfer;
	}
	if (parent->algo->smbus_xfer_atomic)
		priv->algo.smbus_xfer_atomic = priv->algo.smbus_xfer;

	priv->algo.functionality = i2c_mux_functionality;

	/* Now fill out new adapter structure */
	snprintf(priv->adap.name, sizeof(priv->adap.name),
		 "i2c-%d-mux (chan_id %d)", i2c_adapter_id(parent), chan_id);
	priv->adap.owner = THIS_MODULE;
	priv->adap.algo = &priv->algo;
	priv->adap.algo_data = priv;
	priv->adap.dev.parent = &parent->dev;
	priv->adap.retries = parent->retries;
	priv->adap.timeout = parent->timeout;
	priv->adap.quirks = parent->quirks;
	if (muxc->mux_locked)
		priv->adap.lock_ops = &i2c_mux_lock_ops;
	else
		priv->adap.lock_ops = &i2c_parent_lock_ops;

	/* Sanity check on class */
	if (i2c_mux_parent_classes(parent) & class)
		dev_err(&parent->dev,
			"Segment %d behind mux can't share classes with ancestors\n",
			chan_id);
	else
		priv->adap.class = class;

	/*
	 * Try to populate the mux adapter's of_node, expands to
	 * nothing if !CONFIG_OF.
	 */
	if (muxc->dev->of_node) {
		struct device_node *dev_node = muxc->dev->of_node;
		struct device_node *mux_node, *child = NULL;
		u32 reg;

		if (muxc->arbitrator)
			mux_node = of_get_child_by_name(dev_node, "i2c-arb");
		else if (muxc->gate)
			mux_node = of_get_child_by_name(dev_node, "i2c-gate");
		else
			mux_node = of_get_child_by_name(dev_node, "i2c-mux");

		if (mux_node) {
			/* A "reg" property indicates an old-style DT entry */
			if (!of_property_read_u32(mux_node, "reg", &reg)) {
				of_node_put(mux_node);
				mux_node = NULL;
			}
		}

		if (!mux_node)
			mux_node = of_node_get(dev_node);
		else if (muxc->arbitrator || muxc->gate)
			child = of_node_get(mux_node);

		if (!child) {
			for_each_child_of_node(mux_node, child) {
				ret = of_property_read_u32(child, "reg", &reg);
				if (ret)
					continue;
				if (chan_id == reg)
					break;
			}
		}

		priv->adap.dev.of_node = child;
		of_node_put(mux_node);
	}

	/*
	 * Associate the mux channel with an ACPI node.
	 */
	if (has_acpi_companion(muxc->dev))
		acpi_preset_companion(&priv->adap.dev,
				      ACPI_COMPANION(muxc->dev),
				      chan_id);

	if (force_nr) {
		priv->adap.nr = force_nr;
		ret = i2c_add_numbered_adapter(&priv->adap);
		if (ret < 0) {
			dev_err(&parent->dev,
				"failed to add mux-adapter %u as bus %u (error=%d)\n",
				chan_id, force_nr, ret);
			goto err_free_priv;
		}
	} else {
		ret = i2c_add_adapter(&priv->adap);
		if (ret < 0) {
			dev_err(&parent->dev,
				"failed to add mux-adapter %u (error=%d)\n",
				chan_id, ret);
			goto err_free_priv;
		}
	}

	WARN(sysfs_create_link(&priv->adap.dev.kobj, &muxc->dev->kobj,
			       "mux_device"),
	     "can't create symlink to mux device\n");

	snprintf(symlink_name, sizeof(symlink_name), "channel-%u", chan_id);
	WARN(sysfs_create_link(&muxc->dev->kobj, &priv->adap.dev.kobj,
			       symlink_name),
	     "can't create symlink to channel %u\n", chan_id);
	dev_info(&parent->dev, "Added multiplexed i2c bus %d\n",
		 i2c_adapter_id(&priv->adap));

	muxc->adapter[muxc->num_adapters++] = &priv->adap;
	return 0;

err_free_priv:
	kfree(priv);
	return ret;
}