On 17-12-19, 15:03, Pierre-Louis Bossart wrote:
> In the existing SoundWire code, the bus does not have any explicit
> representation for Master Devices - only SoundWire Slaves are exposed.
>
> In SoundWire, the Master Device provides the clock, synchronization
> information and command/control channels. When multiple links are
> supported, a Controller may expose more than one Master Device; they
> are typically embedded inside a larger audio cluster (be it in an
> SOC/chipset or an external audio codec), and we need to describe it
> using the Linux device and driver model. This will allow for
> configuration functions to account for external dependencies such as
> power rails, clock sources or wake-up mechanisms. This transition will
> also allow for better sysfs support without the reference count issues
> mentioned in the initial reviews.
>
> In this patch, we first convert the existing code to use an explicit
> sdw_slave_type and add error checks if this type is not set.
>
> In follow-up patches we can add support for the sdw_master_type.
>
> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
> ---
> drivers/soundwire/bus_type.c | 23 ++++++++++++++++++-----
> drivers/soundwire/slave.c | 7 ++++++-
> include/linux/soundwire/sdw_type.h | 6 ++++++
> 3 files changed, 30 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/soundwire/bus_type.c b/drivers/soundwire/bus_type.c
> index 9a0fd3ee1014..9719680a1e48 100644
> --- a/drivers/soundwire/bus_type.c
> +++ b/drivers/soundwire/bus_type.c
> @@ -49,13 +49,26 @@ int sdw_slave_modalias(const struct sdw_slave *slave, char *buf, size_t size)
>
> static int sdw_uevent(struct device *dev, struct kobj_uevent_env *env)
> {
> - struct sdw_slave *slave = to_sdw_slave_device(dev);
> + struct sdw_slave *slave;
> char modalias[32];
>
> - sdw_slave_modalias(slave, modalias, sizeof(modalias));
> -
> - if (add_uevent_var(env, "MODALIAS=%s", modalias))
> - return -ENOMEM;
> + if (is_sdw_slave(dev)) {
> + slave = to_sdw_slave_device(dev);
> +
> + sdw_slave_modalias(slave, modalias, sizeof(modalias));
> +
> + if (add_uevent_var(env, "MODALIAS=%s", modalias))
> + return -ENOMEM;
> + } else {
> + /*
> + * We only need to handle uevents for the Slave device
> + * type. This error cannot happen unless the .uevent
> + * callback is set to use this function for a
> + * different device type (e.g. Master or Monitor)
> + */
> + dev_err(dev, "uevent for unknown Soundwire type\n");
> + return -EINVAL;
At this point and after next patch, the above code would be a no-op, do
we want this here, if so why?
--
~Vinod
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