Mark Brown broonie@kernel.org writes:
On Sat, Apr 30, 2016 at 11:15:34PM +0200, Robert Jarzmik wrote:
AC97 is a bus for sound usage. It enables for a AC97 AC-Link to link one controller to 0 to 4 AC97 codecs.
The goal of this new implementation is to implement a device/driver model for AC97, with an automatic scan of the bus and automatic discovery of AC97 codec devices.
I think this is basically what I was thinking of, yes. One thing we'll need to do is work out how to handle systems that need some explicit action to start clocks for the bus clock, though they were never very common and it's entirely possible nobody cares any more so perhaps we just punt and see if anyone notices for now.
You probably mean the BITCLK clock.
What is a bit pesky about this clock is that it can either be mastered by digital controller and the codec is a slave, or the other way around.
So we had either the BITCLK provided by : - the controller => this could be passed in ac97_digital_controller_register() - the codec => this is trouble, I don't really know how to handle this case
If the bus code has this clock, it can indeed prepare and enable it.
+int ac97_digital_controller_register(const struct ac97_controller_ops *ops,
struct device *dev);+int ac97_digital_controller_unregister(const struct device *dev);
Why "digital"?
I copy-pasted this from Audio Codec '97 Revision 2.3, where in several places they call the controller a "digital controller".
Quoting chapter 1.4: The digital link that connects the AC ‘97 Digital Controller to the AC ‘97 Codec, referred to as AC-link, is a bi- directional, 5-wire, serial time domain multiplexed (TDM) format interface. AC-link supports connections between a single Controller and up to 4 CODECs on a circuit board and/or riser card.
Now if you prefer "ac97_controller" or something like that, that's as you wish, the name does not matter that much to me ;)
Cheers.