Re: Question about barebox*/drivers/mfd/mc34704.c and ACCURATE I²C mode ...

Re: Question about barebox*/drivers/mfd/mc34704.c and ACCURATE I²C mode ...

[Baruch Siach]

Hi Roland,

On Mon, Apr 16, 2018 at 09:52:14AM +0000, Mainz, Roland wrote:
> Two small questions about drivers/mfd/mc34704.c in the barebox codebase:
> 1. mc34704 has an ACCURATE bit (I2CSET1, see 
> https://www.nxp.com/docs/en/data-sheet/MC34704.pdf) which requires that all 
> read/write commands are send twice - does the barebox code have any support 
> for that in the current versions ?
> 2. Is this "accurate I²C communication mode" enabled by that bit a 
> vendor-specific protocol extension or is it part of the I²C standard ?

Please send your Barebox related questions to the barebox mailing list. I 
added the list to Cc.

To the best of my knowledge there is no "twice" mode in the I2C standard. The 
mc34704 driver does not seem to support this mode.

baruch

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Re: Question about barebox*/drivers/mfd/mc34704.c and ACCURATE I²C mode ...

[Sascha Hauer]

Hi Roland,

On Mon, Apr 16, 2018 at 01:19:39PM +0300, Baruch Siach wrote:
> Hi Roland,
> 
> On Mon, Apr 16, 2018 at 09:52:14AM +0000, Mainz, Roland wrote:
> > Two small questions about drivers/mfd/mc34704.c in the barebox codebase:
> > 1. mc34704 has an ACCURATE bit (I2CSET1, see 
> > https://www.nxp.com/docs/en/data-sheet/MC34704.pdf) which requires that all 
> > read/write commands are send twice - does the barebox code have any support 
> > for that in the current versions ?
> > 2. Is this "accurate I²C communication mode" enabled by that bit a 
> > vendor-specific protocol extension or is it part of the I²C standard ?

I never heard of "accurate I²C", it must be something the chip designers
have invented. Also there is no support for it neither in the mc34704
driver nor in the generic I²C support.

Sascha

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