On 06-01-20, 08:51, Pierre-Louis Bossart wrote: > > > > > > + /* let the SoundWire master driver to its probe */ > > > > > + md->driver->probe(md, link); > > > > > > > > So you are invoking driver probe here.. That is typically role of driver > > > > core to do that.. If we need that, make driver core do that for you! > > > > > > > > That reminds me I am missing match code for master driver... > > > > > > There is no match for the master because it doesn't have an existence in > > > ACPI. There are no _ADR or HID that can be used, the only thing that exists > > > is the Controller which has 4 sublinks. Each master must be added by hand. > > > > > > Also the SoundWire master cannot be enumerated or matched against a > > > SoundWire bus, since it controls the bus itself (that would be a chicken and > > > egg problem). The SoundWire master would need to be matched on a parent bus > > > (which does not exist for Intel) since the hardware is embedded in a larger > > > audio cluster that's visible on PCI only. > > > > > > Currently for Intel platforms, the SoundWire master device is created by the > > > SOF driver (via the abstraction in intel_init.c). > > > > That is okay for me, the thing that is bit confusing is having a probe > > etc and no match.. (more below).. > > > > > > So we seem to be somewhere is middle wrt driver probing here! IIUC this > > > > is not a full master driver, thats okay, but then it is not > > > > completely transparent either... > > > > > > > > I was somehow thinking that the driver will continue to be > > > > 'platform/acpi/of' driver and master device abstraction will be > > > > handled in the core (for example see how the busses like i2c handle > > > > this). The master device is created and used to represent but driver > > > > probing etc is not done > > > > > > I2C controllers are typically PCI devices or have some sort of ACPI > > > description. This is not the case for SoundWire masters on Intel platforms, > > > > Well the world is not PCI/ACPI... We have controllers which are DT > > described and work in same manner as a PCI device. > Both DT and PCI would use a DIFFERENT matching on the parent bus, not a > matching provided by the SoundWire subsystem itself. > > > > > > so even if I wanted to I would have no ability to implement any matching or > > > parent bus registration. > > > > > > Also the notion of 'probe' does not necessarily mean that the device is > > > attached to a bus, we use DAI 'drivers' in ASoC and still have probe/remove > > > callbacks. > > > > The "big" difference is that probe is called by core (asoc) and not by > > driver onto themselves.. IMO that needs to go away. > > What I did is not different from what existed already with platform devices. > They were manually created, weren't they? Manual creation of device based on a requirement is different, did I ask you why you are creating device :) I am simple asking you not to call probe in the driver. If you need that, move it to core! We do not want these kind of things in the drivers... > > > And if you look at the definitions, we added additional callbacks since > > > probe/remove are not enough to deal with hardware restrictions: > > > > > > For Intel platforms, we have a startup() callback which is only invoked once > > > the DSP is powered and the rails stable. Likewise we added an > > > 'autonomous_clock_stop()' callback which will be needed when the Linux > > > driver hands-over control of the hardware to the DSP firmware, e.g. to deal > > > with in-band wakes in D0i3. > > > > > > FWIW, the implementation here follows what was suggested for Greybus 'Host > > > Devices' [1] [2], so it's not like I am creating any sort of dangerous > > > precedent. > > > > > > [1] > > > https://elixir.bootlin.com/linux/latest/source/drivers/greybus/es2.c#L1275 > > > [2] https://elixir.bootlin.com/linux/latest/source/drivers/greybus/hd.c#L124 > > > > And if you look closely all this work is done by core not by drivers! > > Drivers _should_ never do all this, it is the job of core to do that for > > you. > > Please look at the code again, you have a USB probe that will manually call > the GreyBus device creation. > > static int ap_probe(struct usb_interface *interface, > const struct usb_device_id *id) > { > hd = gb_hd_create(&es2_driver, &udev->dev, > > > static struct usb_driver es2_ap_driver = { > .name = "es2_ap_driver", > .probe = ap_probe, <<< code above > .disconnect = ap_disconnect, > .id_table = id_table, > .soft_unbind = 1, > }; Look closely the driver es2 calls into greybus core hd.c and gets the work done, subtle but a big differances in the approaches.. > The master device probe suggested here is also called as part of the parent > SOF PCI device probe, same as this USB example. I really don't see what your > objection is, given that there is no way to deal with the SoundWire > controller as a independent entity for Intel platforms. -- ~Vinod _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
