ASoC legacy i2c client driver probing issue

ASoC legacy i2c client driver probing issue

[Feng Ye]

Hello,

I have a legacy i2c client driver probing issue.
I use kernel version 2.6.27, and wm8750 external codec. The wm8750.c in sound/soc/codecs has a legacy i2c interface (e.g. use attach_adapter() callback). The callback just calls to i2c_probe(). Inside i2c_probe() it checks if the i2c address already been used, and fails there.

In our i2c bus driver, we used i2c_register_board_info() with a static i2c_board_info structure. And then i2c_add_numbered_adapter() is called.
>From code trace, it eventually calls i2c_attach_client(). So I think the probe function will for sure to fail.

I wonder how this would work? How can i2c_probe() succeed if it checks for address in use?
This question is more related to i2c instead of alsa soc. I am sure the SoC part is good, the i2c address is passed to wm8750 through snd_soc_codec_device.



Thanks,
Feng

Re: ASoC legacy i2c client driver probing issue

[rajeev]

Hi Freg

On 5/2/2011 11:48 PM, Feng Ye wrote:
> Hello,
> 
> I have a legacy i2c client driver probing issue.
> I use kernel version 2.6.27, and wm8750 external codec. The wm8750.c in sound/soc/codecs has a legacy i2c interface (e.g. use attach_adapter() callback). The callback just calls to i2c_probe(). Inside i2c_probe() it checks if the i2c address already been used, and fails there.
> 
> In our i2c bus driver, we used i2c_register_board_info() with a static i2c_board_info structure. And then i2c_add_numbered_adapter() is called.

>>From code trace, it eventually calls i2c_attach_client(). So I think the probe function will for sure to fail.
>
How does these two related ? You are calling  i2c_attach_client() then why your probe function will fail.
In fact it will never called. 


 
> I wonder how this would work? How can i2c_probe() succeed if it checks for address in use?
If it is not called then how can you decide whether it succeeded or not?

Rgds
Rajeev
> This question is more related to i2c instead of alsa soc. I am sure the SoC part is good, the i2c address is passed to wm8750 through snd_soc_codec_device.
>
> 
> 
> Thanks,
> Feng
> 
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
> 

Re: ASoC legacy i2c client driver probing issue

[Feng Ye]

I didn't call i2c_attach_client(), it's called from i2c_add_numbered_adapter().

I think the problem is in I2C side: i2c_add_numbered_adapter() is a new interface while attach_adapter() is legacy interface, these two can not work together.
I am trying to port the kernel to newer version so the drivers in sound/soc/codecs uses the new interface (probe()).


Feng


-----Original Message-----
From: rajeev [mailto:rajeev-dlh.kumar@st.com] 
Sent: Tuesday, May 03, 2011 9:56 PM
To: Feng Ye
Cc: alsa-devel@alsa-project.org
Subject: Re: [alsa-devel] ASoC legacy i2c client driver probing issue

Hi Freg

On 5/2/2011 11:48 PM, Feng Ye wrote:
> Hello,
> 
> I have a legacy i2c client driver probing issue.
> I use kernel version 2.6.27, and wm8750 external codec. The wm8750.c in sound/soc/codecs has a legacy i2c interface (e.g. use attach_adapter() callback). The callback just calls to i2c_probe(). Inside i2c_probe() it checks if the i2c address already been used, and fails there.
> 
> In our i2c bus driver, we used i2c_register_board_info() with a static i2c_board_info structure. And then i2c_add_numbered_adapter() is called.

>>From code trace, it eventually calls i2c_attach_client(). So I think the probe function will for sure to fail.
>
How does these two related ? You are calling  i2c_attach_client() then why your probe function will fail.
In fact it will never called. 


 
> I wonder how this would work? How can i2c_probe() succeed if it checks for address in use?
If it is not called then how can you decide whether it succeeded or not?

Rgds
Rajeev
> This question is more related to i2c instead of alsa soc. I am sure the SoC part is good, the i2c address is passed to wm8750 through snd_soc_codec_device.
>
> 
> 
> Thanks,
> Feng
> 
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
> 

Re: ASoC legacy i2c client driver probing issue

[Mark Brown]

On Wed, May 04, 2011 at 10:25:41AM +0530, rajeev wrote:
> On 5/2/2011 11:48 PM, Feng Ye wrote:

Please always CC maintainers on mails, and fix your MUA to word wrap
within paragraphs so your mails are legible.  I've reflowed your text.

> > I use kernel version 2.6.27, and wm8750 external codec. The wm8750.c

Version 2.6.27 is extremely old, none of these issues exist in current
kernels.

> > In our i2c bus driver, we used i2c_register_board_info() with a
> > static i2c_board_info structure. And then i2c_add_numbered_adapter()
> > is called.

With these very old kernels you shouldn't do this.  With modern kernels
you can register the I2C devices normally.