Re: [PATCH v3 11/11] i2c: npcm: Support NPCM845

Andy Shevchenko
2022-03-07T09:51:12Z

On Sun, Mar 06, 2022 at 03:33:20PM +0200, Tomer Maimon wrote:
> On Thu, 3 Mar 2022 at 16:11, Andy Shevchenko <
> andriy.shevchenko@linux.intel.com> wrote:
> > On Thu, Mar 03, 2022 at 02:35:58PM +0200, Tali Perry wrote:
> > > > On Thu, Mar 3, 2022 at 12:45 PM Andy Shevchenko <
> > andriy.shevchenko@linux.intel.com> wrote:

...

> > But hold on and read set of questions below.
> >
> > Previously it was a fixed field with the NPCM_I2CTXF_STS_TX_BYTES mask
> > applied,
> > right? From above I have got that FIFO is growing twice. Is it correct?
>
> What do you mean by growing twice? TX and RX?

I meant from 16 bytes to 32 bytes.

> > Does the LSB stay at the same offset? What is the meaning of the MSB in 32
> > byte
> > case? If it's reserved then why not to always use 32 byte approach?
>
> Yes, the LSB stays in the same place, and bit 5 is reserved in the NPCM7XX
> SoC.
> Unfortunately, the I2C test failed when we tried to use the 32 bytes
> approach at NPCM7XX Soc, this is why we added NPCM_I2CTXF_STS_TX_BYTES and
> NPCM_I2C_STSRXF_RX_BYTES to the data structure.
>
> The device tree data structure pass data for each specific device, so I
> don't understand why not use device tree data for supporting the I2C
> specific device? this is not the case here?

Basically we use compatible strings for that, but in any case if something
can be autodetected from hardware, it's better to use autodetection.

--
With Best Regards,
Andy Shevchenko