I need to gather it together and do some edits, so it makes sense. It will be a few days or so. --- Graham
== On Thursday, December 21, 2017 at 8:19:21 AM UTC-6, ags wrote: > > 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/b470ee64-947e-49a7-a25d-163272f69271%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
