On Tue, Aug 23, 2022 at 09:33:36AM +0200, Martin Povišer wrote:
On 22. 8. 2022, at 19:39, Mark Brown broonie@kernel.org wrote: On Fri, Aug 19, 2022 at 02:54:29PM +0200, Martin Povišer wrote:
+// SPDX-License-Identifier: GPL-2.0-only +/*
- Apple SoCs MCA driver
- Copyright (C) The Asahi Linux Contributors
- The MCA peripheral is made up of a number of identical units called clusters.
Please make the entire comment block a C++ one so things look more intentional.
Is this so that it does not look like the SPDX header was added mechanically? I will do it, just curious what the reasoning is.
Yes, broadly.
- /*
* We can't power up the device earlier than this because* the power state driver would error out on seeing the device* as clock-gated.*/- cl->pd_link = device_link_add(mca->dev, cl->pd_dev,
DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME |DL_FLAG_RPM_ACTIVE);
I'm not clear on this dynamically adding and removing device links stuff
- it looks like the main (only?) purpose is to take a runtime PM
reference to the target device which is fine but it's not clear why device links are involved given that the links are created and destroyed every time the DAI is used, AFAICT always in the same fixed relationship. It's not a problem, it's just unclear.
Indeed the only purpose is powering up the cluster’s power domain (there’s one domain for each cluster). Adding the links is the only way I know to do it. They need to be added dynamically (as opposed to statically linking, say, the DAI’s ->dev to the cluster’s ->pd_dev, which I guess may do something similar), because we need to sequence the power-up/power-down with the enablement of the clocks.
You could also just do the underlying runtime power management operations directly couldn't you? It's not clear what the device link stuff is adding.