On Thu, 19 Oct 2017 05:03:19 +0200,
Vinod Koul wrote:
>
> +/**
> + * sdw_add_bus_master: add a bus Master instance
> + *
> + * @bus: bus instance
> + *
> + * Initializes the bus instance, read properties and create child
> + * devices.
> + */
> +int sdw_add_bus_master(struct sdw_bus *bus)
> +{
> + int ret;
> +
> + if (!bus->dev) {
> + pr_err("SoundWire bus has no device");
> + return -ENODEV;
> + }
> +
> + mutex_init(&bus->bus_lock);
> + INIT_LIST_HEAD(&bus->slaves);
> +
> + /*
> + * 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) && bus->dev && ACPI_HANDLE(bus->dev))
> + ret = sdw_acpi_find_slaves(bus);
> + else if (IS_ENABLED(CONFIG_OF) && bus->dev && bus->dev->of_node)
The bus->dev NULL check is already done at the beginning of the
function, so here are superfluous.
> +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;
> +
> + mutex_lock(&bus->bus_lock);
> + if (!list_empty(&bus->slaves))
> + list_del(&slave->node);
You can perform list_del_init() without empty check.
> +void sdw_extract_slave_id(struct sdw_bus *bus,
> + unsigned long long addr, struct sdw_slave_id *id)
Use u64 instead.
> +{
> + dev_dbg(bus->dev, "SDW Slave Addr: %llx", addr);
> +
> + /*
> + * Spec definition
> + * Register Bit Contents
> + * DevId_0 [7:4] 47:44 sdw_version
> + * DevId_0 [3:0] 43:40 unique_id
> + * DevId_1 39:32 mfg_id [15:8]
> + * DevId_2 31:24 mfg_id [7:0]
> + * DevId_3 23:16 part_id [15:8]
> + * DevId_4 15:08 part_id [7:0]
> + * DevId_5 07:00 class_id
> + */
> + id->sdw_version = (addr >> 44) & GENMASK(3, 0);
> + id->unique_id = (addr >> 40) & GENMASK(3, 0);
> + id->mfg_id = (addr >> 24) & GENMASK(15, 0);
> + id->part_id = (addr >> 8) & GENMASK(15, 0);
> + id->class_id = addr & GENMASK(7, 0);
> +
> + dev_info(bus->dev,
> + "SDW Slave class_id %x, part_id %x, mfg_id %x, unique_id %x, version %x",
> + id->class_id, id->part_id, id->mfg_id,
> + id->unique_id, id->sdw_version);
> +
Do we want to print a message always at each invocation?
> +static int sdw_slave_add(struct sdw_bus *bus,
> + struct sdw_slave_id *id, struct fwnode_handle *fwnode)
> +{
> + struct sdw_slave *slave;
> + char name[32];
> + int ret;
> +
> + slave = kzalloc(sizeof(*slave), GFP_KERNEL);
> + if (!slave)
> + return -ENOMEM;
> +
> + /* Initialize data structure */
> + memcpy(&slave->id, id, sizeof(*id));
> +
> + /* name shall be sdw:link:mfg:part:class:unique */
> + snprintf(name, sizeof(name), "sdw:%x:%x:%x:%x:%x",
> + bus->link_id, id->mfg_id, id->part_id,
> + id->class_id, id->unique_id);
You can set the name directly via dev_set_name(). It's printf format,
after all.
> + slave->dev.parent = bus->dev;
> + slave->dev.fwnode = fwnode;
> + dev_set_name(&slave->dev, "%s", name);
> + slave->dev.release = sdw_slave_release;
> + slave->dev.bus = &sdw_bus_type;
> + slave->bus = bus;
> + slave->status = SDW_SLAVE_UNATTACHED;
> + slave->dev_num = 0;
> +
> + mutex_lock(&bus->bus_lock);
> + list_add_tail(&slave->node, &bus->slaves);
> + mutex_unlock(&bus->bus_lock);
> +
> + ret = device_register(&slave->dev);
> + if (ret) {
> + dev_err(bus->dev, "Failed to add slave: ret %d\n", ret);
> +
> + /*
> + * On err, don't free but drop ref as this will be freed
> + * when release method is invoked.
> + */
> + put_device(&slave->dev);
Wouldn't it leave a stale link to bus?
thanks,
Takashi
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