Re: [PATCH 1/7] ASoC: SDCA: Factor out jack handling into new c file

[Charles Keepax <ckeepax@opensource.cirrus.com>]

On Tue, Dec 09, 2025 at 12:00:24PM +0000, Pierre-Louis Bossart wrote:
> > +	switch (val) {
> > +	case SDCA_DETECTED_MODE_DETECTION_IN_PROGRESS:
> > +	case SDCA_DETECTED_MODE_JACK_UNKNOWN:
> > +		reg = SDW_SDCA_CTL(interrupt->function->desc->adr,
> > +				   interrupt->entity->id,
> > +				   SDCA_CTL_GE_SELECTED_MODE, 0);
> > +
> > +		/*
> > +		 * Selected mode is not normally marked as volatile register
> > +		 * (RW), but here force a read from the hardware. If the
> > +		 * detected mode is unknown we need to see what the device
> > +		 * selected as a "safe" option.
> > +		 */
> > +		regcache_drop_region(interrupt->function_regmap, reg, reg);
> > +
> > +		ret = regmap_read(interrupt->function_regmap, reg, &val);
> > +		if (ret) {
> > +			dev_err(dev, "failed to re-check selected mode: %d\n", ret);
> > +			return ret;
> > +		}
> 
> The detected_mode is reported by hardware and copied into the
> selected_mode, but that's not the end of it.
> We should capture with at least a comment that the intent of
> the SDCA design was to let the user or additional vendor-specific
> override the selected mode. If/when we have to deal with the
> complicated multi-jack topologies it'll be required.

So the theory is we are already supporting this. The jack handler
here will report the "safe" accessory type returned by the device.
But the detected mode and selected mode are exposed as ALSA
controls to user-space, so if the user wants to adjust the
accessory type they can just set the selected mode control. If
vendors want to do in driver vendor magic they will need to
register their own IRQ handler for the detected mode control, but
we provide for that through the sdca_irq_request() API.

Thanks,
Charles