This is very old, but I'm still interested in using I2S to directly drive an audio device (software defined radio module). Could you post your write-up if available? Thanks.
On Tuesday, May 16, 2017 at 11:21:30 AM UTC-7, Graham wrote: > > It will be a day or so, but I will post the write-up here. > > You will not be able to control the IC independently, since the kernel > claims the device. > The Linux audio system expects to be able to control the audio controls > such as volume, etc. > by reaching into the CODEC through the control bus. The kernel blocks > direct user > space access to the device. > > In fact one way to make sure the device tree loaded correctly is that the > "UU" symbol > appears at the devices' I2C address. > > --- Graham > > == > > On Tuesday, May 16, 2017 at 10:51:19 AM UTC-5, ags wrote: >> >> I would appreciate the writeup, thank you. >> >> My project requires interfacing to an IC with I2S input. I planned on >> using (something like) aplay to write audio out to I2S/McASP channel (using >> built-in driver support) and hoped I could also use the built-in support >> (drivers) for SPI and/or I2C using the /dev/spidev<x.y> or /dev/i2c-<n> >> devices to control the IC. >> >> On Monday, May 15, 2017 at 6:46:50 PM UTC-7, Graham wrote: >>> >>> Yes, I was able to get a CircuitCo Rev.B Audio cape running, using the >>> I2S/McASP interface. >>> I'll write it up for you, if you are interested. >>> >>> If you are going to use a different CODEC or other device on the >>> I2S/McASP interface, >>> you will need to see if a driver already exists for it, or if it fits a >>> generalized I2S audio interface that >>> is already inside the kernel can be invoked and controlled from a device >>> tree. >>> >>> If it is unique, then you will have to write your own Linux driver and >>> recompile the kernel. >>> >>> If you just want audio, it is a lot easier to just use a USB CODEC. >>> >>> --- Graham >>> >>> == >>> >>> On Monday, May 15, 2017 at 6:11:11 PM UTC-5, ags wrote: >>>> >>>> I'm also interested as I have a project where I will interface directly >>>> to the I2S/McASP interface. Did you figure it out? >>>> >>>> >>>> On Tuesday, January 3, 2017 at 8:57:29 AM UTC-8, Graham wrote: >>>>> >>>>> I spent most of the weekend down in the rabbit-hole, trying to get a >>>>> CircuitCo Rev_B Audio cape to work, (unsuccessfully.) >>>>> >>>>> Is this cape compatible-with / supported-by Debian 8.6/kernel 4.4 ? >>>>> >>>>> Does the BB-BONE-AUDI-02-00A0.dtbo overlay that comes with the current >>>>> distribution work? >>>>> >>>>> How can you tell if an overlay actually loaded, with 4.4? >>>>> /sys/devices/platform/bone_capemgr/slots >>>>> as well as the boot log, only shows the first physical four, and no >>>>> longer shows the higher numbered "pseudo-capes" and overlay status. >>>>> >>>>> I understand that >>>>> The CircuitCo cape does not have an EEPROM, so everything needs to be >>>>> configured explicitly. >>>>> I need to use a base .dts with HDMI audio disabled, then load the >>>>> overlay for the CircuitCo card. >>>>> I also need to load the asound.state file. >>>>> >>>>> Am I approaching this correctly? >>>>> >>>>> I can not use a USB-soundcard for audio. I have several applications >>>>> that need McASP/I2S running for several other codecs, but I thought I >>>>> would start >>>>> with the CircuitCo cape as a starting point. >>>>> >>>>> Thanks, >>>>> --- Graham >>>>> >>>>> == >>>>> >>>>> -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/3b1bb63a-326a-4822-9835-6bbf3439db63%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
