Re: [PATCH] add hardware I2C support for ARM IMX23

Re: [PATCH] add hardware I2C support for ARM IMX23

[Wolfram Sang]

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Hi,

(adding the i2c list)

On Wed, Nov 28, 2012 at 05:44:49PM +0100, Sander van Ginkel wrote:
> tested with:
> CONFIG_I2C_MXS=m
> CONFIG_I2C_MXS=y
> 
> in combination with CONFIG_GPIO_MXS enabled and disabled
> 
> used kernels: 3.6 and 3.7.0-rc6
> 
> My I2C slave is a PCF8575 i/o expander with some LEDs at the output.
> These are controlled through sysfs.

Thanks, this is useful info.

> Just tested with "i2cdetc -y -r 0" that crashes with  "BUG: soft
> lockup - CPU#0 stuck for 22s!"
> according to the docs (IMX23RM.pdf) the interrupts for I2C are 26
> and 27 that why I assigned these two in the dts.

You might want to try my for-next branch or wait for 3.8-rc1, maybe the
DMA termination patch helps? Also enabling I2C debug messages is
probably worth it.

Regards,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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Re: [PATCH] add hardware I2C support for ARM IMX23

[sander van ginkel]

Citeren "Wolfram Sang" <w.sang@pengutronix.de>:

>
> You might want to try my for-next branch or wait for 3.8-rc1, maybe
the
> DMA termination patch helps? Also enabling I2C debug messages is
> probably worth it.
>
> Regards,
>
>    Wolfram
>
> --
> Pengutronix e.K.                           | Wolfram Sang
      |
> Industrial Linux Solutions                 |
http://www.pengutronix.de/  |
>

Ok I will dig into this, your for-next branch contains the DMA  
termination patch, I presume?

Re: [PATCH] add hardware I2C support for ARM IMX23

[sander van ginkel]

> You might want to try my for-next branch or wait for 3.8-rc1, maybe
the
> DMA termination patch helps? Also enabling I2C debug messages is
> probably worth it.
>
> Regards,
>
>    Wolfram
>
> --
> Pengutronix e.K.                           | Wolfram Sang
      |
> Industrial Linux Solutions                 |
http://www.pengutronix.de/  |
>

I've tested your git tree, with the same config as I used for the  
3.7.0-rc6 release (IMX i2c build in)
It's not a 100% fix

If I do "i2cdetect -y -r 0" with 3.7.0-rc6, i2cdetect gets confused  
and the kernel keeps dumping "mxs-i2c 80058000.i2c: Failed to get PIO  
reg. write descriptor."
If I do the same with your git release I get the same result, but only  
when i2cdetect is running. When it's finished or I terminate, the  
kprint will also disappear.
So there is some improvement but not 100% yet.