Re: [PATCH v1 1/8] i2c: Introduce i2c_10bit_addr_from_msg()

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Wed, Feb 12, 2025 at 07:36:46PM +0100, Geert Uytterhoeven wrote:
> On Wed, 12 Feb 2025 at 17:35, Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > There are already a lot of drivers that have been using
> > i2c_8bit_addr_from_msg() for 7-bit addresses, now it's time
> > to have the similar for 10-bit addresses.

...

> > +static inline u8 i2c_10bit_addr_from_msg(const struct i2c_msg *msg)
> 
> Having never used 10-bit addressing myself, or even looked into it,
> it took me a while to understand what this helper really does...
> So this returns the high byte of the artificial 16-bit address that
> must be used to address a target that uses 10-bit addressing?
> Hence I think this should be renamed, to better match its purpose.

Since you are giving a constructive feedback, please, propose the name.

> > +{
> > +       /*
> > +        * 10-bit address
> > +        *   addr_1: 5'b11110 | addr[9:8] | (R/nW)
> > +        *   addr_2: addr[7:0]
> 
> I think the second comment line does not belong here, as this function
> doesn't care about that part.

I think the comment is okay to stay. It explains the full picture which is
helpful. It may be extended to say that the function returns only addr_1.

> > +        */
> > +       return 0xf0 | ((msg->addr & GENMASK(9, 8)) >> 7) | (msg->flags & I2C_M_RD);
> > +}
> 
> Probably you also want to add a similar but much simpler helper to
> return the low byte?

Wouldn't it be too much?

-- 
With Best Regards,
Andy Shevchenko