int sdw_bus_master_add()

in bus.c [35:145]

• 66 lines of code
• 13 McCabe index (conditional complexity)

int sdw_bus_master_add(struct sdw_bus *bus, struct device *parent,
		       struct fwnode_handle *fwnode)
{
	struct sdw_master_prop *prop = NULL;
	int ret;

	if (!parent) {
		pr_err("SoundWire parent device is not set\n");
		return -ENODEV;
	}

	ret = sdw_get_id(bus);
	if (ret < 0) {
		dev_err(parent, "Failed to get bus id\n");
		return ret;
	}

	ret = sdw_master_device_add(bus, parent, fwnode);
	if (ret < 0) {
		dev_err(parent, "Failed to add master device at link %d\n",
			bus->link_id);
		return ret;
	}

	if (!bus->ops) {
		dev_err(bus->dev, "SoundWire Bus ops are not set\n");
		return -EINVAL;
	}

	if (!bus->compute_params) {
		dev_err(bus->dev,
			"Bandwidth allocation not configured, compute_params no set\n");
		return -EINVAL;
	}

	mutex_init(&bus->msg_lock);
	mutex_init(&bus->bus_lock);
	INIT_LIST_HEAD(&bus->slaves);
	INIT_LIST_HEAD(&bus->m_rt_list);

	/*
	 * Initialize multi_link flag
	 * TODO: populate this flag by reading property from FW node
	 */
	bus->multi_link = false;
	if (bus->ops->read_prop) {
		ret = bus->ops->read_prop(bus);
		if (ret < 0) {
			dev_err(bus->dev,
				"Bus read properties failed:%d\n", ret);
			return ret;
		}
	}

	sdw_bus_debugfs_init(bus);

	/*
	 * Device numbers in SoundWire are 0 through 15. Enumeration device
	 * number (0), Broadcast device number (15), Group numbers (12 and
	 * 13) and Master device number (14) are not used for assignment so
	 * mask these and other higher bits.
	 */

	/* Set higher order bits */
	*bus->assigned = ~GENMASK(SDW_BROADCAST_DEV_NUM, SDW_ENUM_DEV_NUM);

	/* Set enumuration device number and broadcast device number */
	set_bit(SDW_ENUM_DEV_NUM, bus->assigned);
	set_bit(SDW_BROADCAST_DEV_NUM, bus->assigned);

	/* Set group device numbers and master device number */
	set_bit(SDW_GROUP12_DEV_NUM, bus->assigned);
	set_bit(SDW_GROUP13_DEV_NUM, bus->assigned);
	set_bit(SDW_MASTER_DEV_NUM, bus->assigned);

	/*
	 * SDW is an enumerable bus, but devices can be powered off. So,
	 * they won't be able to report as present.
	 *
	 * Create Slave devices based on Slaves described in
	 * the respective firmware (ACPI/DT)
	 */
	if (IS_ENABLED(CONFIG_ACPI) && ACPI_HANDLE(bus->dev))
		ret = sdw_acpi_find_slaves(bus);
	else if (IS_ENABLED(CONFIG_OF) && bus->dev->of_node)
		ret = sdw_of_find_slaves(bus);
	else
		ret = -ENOTSUPP; /* No ACPI/DT so error out */

	if (ret < 0) {
		dev_err(bus->dev, "Finding slaves failed:%d\n", ret);
		return ret;
	}

	/*
	 * Initialize clock values based on Master properties. The max
	 * frequency is read from max_clk_freq property. Current assumption
	 * is that the bus will start at highest clock frequency when
	 * powered on.
	 *
	 * Default active bank will be 0 as out of reset the Slaves have
	 * to start with bank 0 (Table 40 of Spec)
	 */
	prop = &bus->prop;
	bus->params.max_dr_freq = prop->max_clk_freq * SDW_DOUBLE_RATE_FACTOR;
	bus->params.curr_dr_freq = bus->params.max_dr_freq;
	bus->params.curr_bank = SDW_BANK0;
	bus->params.next_bank = SDW_BANK1;

	return 0;
}