Updating wm8753 codec

Circuits · n00b Joined: 16 Oct 2018 Posts: 6

I am new to these forums but by chance I stumbled across this thread: https://forums.gentoo.org/viewtopic-t-842411-start-50.html while searching for solutions to my problem. Let it be known that I am more of a software guy than a hardware guy but as fate would have it my first hardware experience is updating an EOL codec with one that is still in production. Essentially, I am working on a legacy kernel (2.6.35.14) with legacy systems and I am rather new to Linux in general so it has been a double struggle for me to get this far. Specifically, one of our legacy products audio codec is no longer sold but the product itself is still being sold. So the hardware boys decided to replace the EOL codec () with the codec and its up to me to get it working.

After some time an effort (never configured a Linux kernel before) I have figured out how to get my wm8750 configured s/t the kernel see's it. I have also started messing around with the old machine or "glue" driver for the EOL codec in an attempt to make it work for the new codec. I think I have it but apparently not?? After making changes to the machine driver and building the kernel I tried booting up the system and I logged the process. I am getting the following error in my log:

Hardware is initialized using a guess method
alsactl: set_control:1255: failed to obtain info for control #2 (No such file or directory)
alsactl: set_control:1255: failed to obtain info for control #6 (No such file or directory)
alsactl: set_control:1255: failed to obtain info for control #7 (No such file or directory)

it goes on attempting this set_control quite a few more times.

So does this mean my machine driver is built incorrectly or is there something else that I need to do in order to get the wm8750 hardware initialized properly? I realize this could require more information so if that is the case please feel free to ask. I could post datasheets, circuit diagrams, code, pictures of the configuration (menuconfig)... you name it.

Jaglover · Posted: Tue Oct 16, 2018 8:46 pm Post subject:

Welcome to the forums.

Myself and probably other members here are not familiar with this hardware. So the first question is how it is connected? PCI, USB, something else?
Please note, these forums do not allow long logs, if you wish to share logs or kernel config with us please use some pastebin site. Gentoo has wgetpaste utility for this, not sure if you have this at your disposal.
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Circuits · n00b Joined: 16 Oct 2018 Posts: 6

@Jaglover This is embedded Linux ALSA SoC for an i.MX CCWMX51 board.

Jaglover · Posted: Tue Oct 16, 2018 9:25 pm Post subject:

Generally, if the ALSA device driver is loaded you will get nodes in /dev/snd and all applications can use them. Unless there is some permission issue. OTOH, this is a very old kernel version and apparently you are using some embedded Linux? I don't think I can be much help here.

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John R. Graham · Posted: Tue Oct 16, 2018 9:46 pm Post subject:

Moved from Kernel & Hardware to Unsupported Software. Not about Gentoo so it fits better here.

- John
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Circuits · n00b Joined: 16 Oct 2018 Posts: 6

@John R. Graham Ah I see sorry about that.

John R. Graham · Posted: Tue Oct 16, 2018 9:50 pm Post subject:

No worries. Also, "Unsupported Software" is, in fact, a support forum.

- John
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khayyam · Posted: Tue Oct 16, 2018 11:43 pm Post subject: Re: Updating wm8753 codec

Hu · Moderator Joined: 06 Mar 2007 Posts: 21607

I suspect the answer will be that you have a good reason not to upgrade, but on the off chance that you can, I strongly encourage you to try a more recent kernel. It may not be relevant to your immediate problem, but it is a good idea in principle. You may also find more people knowledgeable about the relevant subsystems in a contemporary kernel than knowledgeable about an old and mostly abandoned kernel.

Circuits · n00b Joined: 16 Oct 2018 Posts: 6

khayyam · Posted: Sat Oct 20, 2018 11:22 am Post subject: Re: Updating wm8753 codec

Jaglover · Posted: Sat Oct 20, 2018 1:58 pm Post subject:

I did a little reading, the whole ALSA SoC seems a little messy hardware-wise.
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Circuits · n00b Joined: 16 Oct 2018 Posts: 6

Well I am not an EE but I was looking at the Datasheet for the wm8750. There is a diagram in there that shows 5 pins being hooked up between the codec and the bus. However, the boys in hardware drove one of those connections to ground.
Unfortunately, this kernel was customized by Digi and updating it would apparently be too hard to do so that is why it has not been updated.

Jaglover · Posted: Mon Oct 22, 2018 4:58 pm Post subject:

Look here: https://elixir.bootlin.com/linux/latest/source/sound/soc/codecs/wm8753.c

^^ This is the latest.

And this is yours: https://elixir.bootlin.com/linux/v2.6.35.14/source/sound/soc/codecs/wm8753.c

You may get away just by editing the source and adding the identifier of your version of WM8753.
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Circuits · n00b Joined: 16 Oct 2018 Posts: 6

Maybe I haven't been clear on what I a have done and what I need to do (not supersizing) considering it's all a bit foggy for me. I am trying to update the codec to a codec (53 to 50). Both codecs are part of the kernel so I did not have to add the 50 it was already there. What I did was configured the kernel s/t it no longer looked for the instead it looked for the 50. Then what I did was edit the old machine driver for the 53 in an attempt to convert it s/t it would work for the 50 codec. I haven't actual touched the codec at all as the philosophy (from what I understand) behind the ASoC system was to: change the machine driver and not the codec. I must have made those configuration adjustments correctly because during the boot process it's not looking for a its looking (correctly) for the 50. Why it can't find it... I am not sure.

@Jaglover I hope this makes it more clear what I am trying to do? So touching the codec won't be necessary for me. Unless... are you suggesting that the codec for the code that I have in my kernel isn't going to work becasue the hardware we purchased actually needs to operate on a newer updated version for the code and not the code that was already in the kernel?

Jaglover · Posted: Mon Oct 22, 2018 10:00 pm Post subject:

Yeah, my bad. This thread has been going on for some time now, I forgot how it started. Anyhow, to get the driver load it needs to identify the piece of hardware. For PCI devices it is the PCI ID, for instance.
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