drivers/soundwire/bus.c

Source file repositories/reference/linux-study-clean/drivers/soundwire/bus.c

File Facts

System
Linux kernel
Corpus path
drivers/soundwire/bus.c
Extension
.c
Size
52581 bytes
Lines
2129
Domain
Driver Families
Bucket
drivers/soundwire
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

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 enumeration 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);

	ret = sdw_irq_create(bus, fwnode);
	if (ret)
		return ret;

	/*
	 * 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);
		sdw_irq_delete(bus);
		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;
}
EXPORT_SYMBOL(sdw_bus_master_add);

static int sdw_delete_slave(struct device *dev, void *data)
{
	struct sdw_slave *slave = dev_to_sdw_dev(dev);
	struct sdw_bus *bus = slave->bus;

	pm_runtime_disable(dev);

	sdw_slave_debugfs_exit(slave);

	mutex_lock(&bus->bus_lock);

	if (slave->dev_num) { /* clear dev_num if assigned */
		clear_bit(slave->dev_num, bus->assigned);
		if (bus->ops && bus->ops->put_device_num)
			bus->ops->put_device_num(bus, slave);
	}
	list_del_init(&slave->node);
	mutex_unlock(&bus->bus_lock);

Annotation

Implementation Notes