Try the attached DTS and make the necessary changes. The DTS you are working
from doesn¹t make any sense to me. Looking at the serializer, 1 is for TX,
but the GPIO shows AXR3 as an input. Also, the DTS doesn¹t show have a mux
for both AXR0 and AXR3. BTW, each channel is a stereo channel, supporting
both left and right audio streams.

Regards,
John
From:  Jesse Forgues <[email protected]>
Reply-To:  "[email protected]" <[email protected]>
Date:  Friday, June 13, 2014 at 6:27 PM
To:  "[email protected]" <[email protected]>
Subject:  [beagleboard] Changing BB-BONE-AUDI-02-00A0 from McASP AXR2 to
AXR3

> So I wanted to make my own audio cape with 4 channels (and eventually 8).
> Picture: 
> https://dl.dropboxusercontent.com/u/82765462/BBB/4channel_audioCape.jpg
> 
> Right now I am running the clocks and i2s to a multichannel USB ADC/DAC which
> is working great off AXR2.
> 
> A basic first step is I wanted to change the boardzoo audio cape to using
> McASP_AXR3 by changing the device tree for BB-BONE-AUDI-02-00A0.dts from AXR2
> to AXR3.
> 
> First off the comments in the dts file seem incorrect in some cases but thats
> ok, I got through it.
> 
> So I changed in the default dts file:
> From:
> /* state the resources this cape uses */
> 
> exclusive-use =
> 
> /* the pin header uses */
> 
> "P9.31", /* mcasp0: mcasp0_aclkx */
> 
> "P9.29", /* mcasp0: mcasp0_fsx */
> 
> "P9.28", /* mcasp0: mcasp0_axr2 */
> 
> "P9.25", /* mcasp0: mcasp0_ahclkx */
> 
> /* the hardware ip uses */
> 
> "gpio1_18", "gpio1_19",
> 
> "mcasp0";
> 
> To:
> /* state the resources this cape uses */
> 
> exclusive-use =
> 
> /* the pin header uses */
> 
> "P9.31", /* mcasp0: mcasp0_aclkx */
> 
> "P9.29", /* mcasp0: mcasp0_fsx */
> 
> "P9.27", /* mcasp0: mcasp0_axr3 */
> 
> "P9.25", /* mcasp0: mcasp0_ahclkx */
> 
> /* the hardware ip uses */
> 
> "gpio1_18", "gpio1_19",
> 
> "mcasp0";
> 
> 
> And the pinmux from:
> bone_audio_cape_audio_pins: pinmux_bone_audio_cape_audio_pins {
> 
> pinctrl-single,pins = <
> 
> 0x1ac 0x00      /* mcasp0_ahclkx,             MODE0 | INPUT */
> 
> 0x19c 0x22 /* mcasp0_axr2, */
> 
> 0x194 0x20      /* mcasp0_fsx,               MODE0 | OUTPUT  */
> 
> 0x190 0x20      /* mcasp0_aclkr.mcasp0_aclkx, MODE0 | OUTPUT_PULLDOWN */
> 
> 0x198 0x20
> 
>> >;
> 
> 
> 
> To:
> 
> 
> 
> bone_audio_cape_audio_pins: pinmux_bone_audio_cape_audio_pins {
> 
> pinctrl-single,pins = <
> 
> 0x1ac 0x00      /* mcasp0_ahclkx,             MODE0 | INPUT */
> 
> 0x1a4 0x22 /* mcasp0_axr3, */
> 
> 0x194 0x20      /* mcasp0_fsx,               MODE0 | OUTPUT  */
> 
> 0x190 0x20      /* mcasp0_aclkr.mcasp0_aclkx, MODE0 | OUTPUT_PULLDOWN */
> 
> 0x198 0x20
> 
>> >;
> 
> 
> 
> Also changed the serializer from:
> 
> 
> 
> op-mode = <0>;          /* MCASP_IIS_MODE */
> 
> tdm-slots = <2>;
> 
> num-serializer = <16>;
> 
> serial-dir = <  /* 0: INACTIVE, 1: TX, 2: RX */
> 
> 2 0 1 0
> 
> 0 0 0 0
> 
> 0 0 0 0
> 
> 0 0 0 0
> 
>> >;
> 
> tx-num-evt = <1>;
> 
> rx-num-evt = <1>;
> 
> };
> 
> 
> 
> To:
> 
> 
> 
> op-mode = <0>;          /* MCASP_IIS_MODE */
> 
> tdm-slots = <2>;
> 
> num-serializer = <16>;
> 
> serial-dir = <  /* 0: INACTIVE, 1: TX, 2: RX */
> 
> 2 0 0 1
> 
> 0 0 0 0
> 
> 0 0 0 0
> 
> 0 0 0 0
> 
>> >;
> 
> tx-num-evt = <1>;
> 
> rx-num-evt = <1>;
> 
> };
> 
> };
> 
> 
> 
> Original file: 
> https://dl.dropboxusercontent.com/u/82765462/BBB/BB-BONE-AUDI-02-00A0.dts
> 
> AXR2 to AXR3 changes outlined above:
> https://dl.dropboxusercontent.com/u/82765462/BBB/BB-BONE-AUDI-02-00A0swap.dts
> 
> 
> 
> Then I simply did:
> 
> cd /lib/firmware
> dtc -O dtb -o BB-BONE-AUDI-02-00A0.dtbo -b 0 -@ BB-BONE-AUDI-02-00A0swap.dts
> And reboot. 
> When I play audio though it still comes out the old AXR2 i2s!!!
> 
> Eventually I want both AXR2 and AXR3 so I can get 2 stereo channels output.
> Then eventually 6 channels, 8 etc... what HDMI intended...
> 
> Anyways! Wondering where I went wrong in the device tree before I start
> mucking with tlv320aic3x.c, davinci-mcasp.c and davinci-evm.c
> 
> Thanks in advance!
> -Jesse
> -- 
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Attachment: BB-BONE-AUDI-03-00A0.dts
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