Re: [PATCH 1/2] dt-bindings: i2c: Add MediaTek i2c AC timing binding

From: Qii Wang
Date: Wed Jul 17 2019 - 08:55:42 EST


On Wed, 2019-06-26 at 15:39 +0200, Wolfram Sang wrote:
> Hi,
>
> On Tue, Jun 11, 2019 at 04:11:54PM +0800, Qii Wang wrote:
> > Add i2c AC timing binding to binding file. It can give the AC
> > timing parameters to meet I2C specification at different speed.
> >
> > Signed-off-by: Qii Wang <qii.wang@xxxxxxxxxxxx>
>
> I think this is a too specific 1:1 mapping of your register set into DT
> world. We already have these generic parameters:
>
> - clock-frequency
> frequency of bus clock in Hz.
>
> - i2c-scl-falling-time-ns
> Number of nanoseconds the SCL signal takes to fall; t(f) in the I2C
> specification.
>
> - i2c-scl-internal-delay-ns
> Number of nanoseconds the IP core additionally needs to setup SCL.
>
> - i2c-scl-rising-time-ns
> Number of nanoseconds the SCL signal takes to rise; t(r) in the I2C
> specification.
>
> - i2c-sda-falling-time-ns
> Number of nanoseconds the SDA signal takes to fall; t(f) in the I2C
> specification.
>
> (check Documentation/devicetree/bindings/i2c/i2c.txt)
>
> Can't you use those to derive your values from that? Which ones are you missing
> if not?
>
> Regards,
>
> Wolfram

I have take a little time to develop a new patch which based on your
suggestions, and it tested OK. Thanks for your suggestions, I will
update the patch after I test it fully.