On Sat, Apr 18, 2015 at 06:34:07PM +0100, Mark Brown wrote: > On Fri, Apr 10, 2015 at 04:14:07PM +0800, Koro Chen wrote: > > > +Each external interface (called "IO" in this driver) is presented as a > > +DAI to ASoC. An IO must be connected via the interconnect to a memif. > > +The connection paths are configured through the device tree. > > Why are these connection paths configured via device tree? I would > expect that either there would be runtime configurability of these > things (particularly if loopback configurations within the hardware are > possible) or we'd just allocate memory interfaces to DAIs automatically > as DAIs come into use. There is a crossbar switch between the memory interfaces and the DAIs. Not every connection is possible, so not every memory interface can be used for every DAI. An algorithm choosing a suitable memory interface must be quite clever, complicated and also SoC dependent (the same but different hardware is used on MT8135 aswell), so I thought offering a static configuration via device tree is a good start. Should there be runtime configuration possible later the device tree settings could provide a good default. > > > +- mem-interface-playback: > > + mem-interface-capture: property of memif, format is: <memif irq use_sram>; > > + memif: which memif to be used > > + (defined in include/dt-bindings/sound/mtk-afe.h) > > + irq: which irq to be used > > + (defined in include/dt-bindings/sound/mtk-afe.h) > > + use_sram: 1 is yes, 0 is no > > Again, this looks like stuff we should be able to figure out at runtime > - the use of SRAM in particular looks like something we might want to > change depending on use case. Assuming it adds buffering then for a > VoIP application we might not want to use SRAM to minimize latency but > during music playback we might want to enable SRAM to minimize power > consumption. That's exactly the usecase. How could such a runtime configurability look like? sysfs? Or something based on the buffer sizes? Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
