Re: [PATCH v6] i2c: add support for Zhaoxin I2C controller

[Andi Shyti <andi.shyti@kernel.org>]

Hi Hans,

> > > + * registers
> > > + */
> > > +/* I2C MMIO Address Constants */
> > > +#define ZXI2C_CR_L                     0x00
> > > +#define   ZXI2C_CPU_RDY          BIT(3)
> > > +#define   ZXI2C_TX_END           BIT(2)
> > > +#define   ZXI2C_RX_ACK           BIT(1)
> > The register layout looks similar to the i2c-wmt driver. Could this
> > driver maybe be reused for your hardware? I'll stop reviewing here
> > because we need to have that clear first.
> > 
> > Thank you and happy hacking,
> > 
> >     Wolfram
> > 
> 
> I just learned that they are indeed derived from the same VIA I2C IP.
> The relationship between WonderMedia/VIA/Zhaoxin looks like this:
> * The i2c-wmt.c driver is used on the WonderMedia/VT8500 platform,
>   an ARM-based SOC from VIA. This SOC hasn't been updated in years.
>   Its MAINTAINERS are also Orphan.
> * Lots of VIA IP is now owned by Zhaoxin, including I2C, SMBus, etc.
>   Zhaoxin adds some new features on the basis of the original I2C IP,
>   such as FIFO mode. And there are plans to continue adding new
>   features.
> 
> Based on this information, we thought it might be more maintainable
> to create a new driver file.

I think I commented about this some times ago but then forgot.
The two drivers are, indeed, very similar.

We could eventually create a *-common.{c,h} file.

Andi