Re: [PATCH v4 2/6] PCI: spacemit-k1: Add multiple PHY handles support

[Andy Shevchenko]

On Fri, Jul 10, 2026 at 06:55:10PM +0800, Inochi Amaoto wrote:
> On Fri, Jul 10, 2026 at 11:07:40AM +0300, Andy Shevchenko wrote:
> > On Fri, Jul 10, 2026 at 09:57:05AM +0800, Inochi Amaoto wrote:
> > > On Thu, Jul 09, 2026 at 10:16:28AM +0300, Andy Shevchenko wrote:
> > > > On Thu, Jul 09, 2026 at 12:00:22PM +0800, Inochi Amaoto wrote:

...

> > > > > +	k1->phy_count = i;
> > > > > +	if (k1->phy_count == 0)
> > > > > +		return -EINVAL;
> > > > > +
> > > > > +	return 0;
> > > > 
> > > > This doesn't seem correct to me, I would expect phy_count to be assigned only
> > > > when it's valid. (Yes, perhaps 0 is the same as it was, but semantically it's
> > > > different 0 in this case.)
> > > 
> > > I guess you think 0 is a valid number? I can not understand what you thing
> > > Assign this to 0 if there is no phy is fine to me, which shows there is 0
> > > vaild phy found.
> > 
> > Isn't it already 0? Semantically code is wrong in a flow (not in the result).
> 
> In fact it is already 0 here. But I am not understand why you thing is wrong.
> Could you explain it in detail? (Maybe you think it is not good to return 
> -EINVAL?)

You rewrite 0 by 0, but the fact of the rewriting is inaccuracy.
We should not rewrite the default (whatever it is) with 0 count
as semantically they are different cases. The rule of thumb, we
don't assign values in case of errors, we leave them as is and
it's user / caller responsibility to assign the default and handle
errors properly. This is simple layering violation.

Your code should be

	if (i == 0)
		return -EINVAL;

	k1->phy_count = i;
	return 0;

> > > > See also above. Do we have some PHY API that just counts provided PHYs?
> > > > If not, that what you should probably add first, before this patch.
> > > 
> > > I have not found any api for this. But the actual problem is, how the api
> > > is designed. I have checked both the array bulk api for reset and clock,
> > > it seems like it is much more than this patch...
> > 
> > Yeah, I looked at the phy-core and I think it will be hard to implement.
> > So, the idea is then is to reallocate the pointer each time you get a new PHY.
> > In this case the phy_count will reflect the actual memory consumption by phy.
> 
> Emmm, I think it is kind of buggy and not necessary. In most case
> this array is not long actually, so allocate some pointer should be
> fine and be an acceptable cost.

Then the counted_by will be incorrect as it may access valid memory, but
unused by the driver.

...

> > > > > +	for (i = 0; i < k1->phy_count; i++)
> > > > 
> > > > 	for (unsigned int i = 0; i < k1->phy_count; i++)
> > > > 
> > > 
> > > I agree with the unsigned int, but I guess this definition is not
> > > allowed in linux.
> > 
> > It's allowed and it's encouraged even by Linus. As long as iterator is local,
> > use this syntax sugar and reduce its scope. It hardens the code.
> 
> Could you give me a reference url to check,

Sure, there are two (one for integers and one for pointers)
https://lore.kernel.org/lkml/CAHk-=wiCOTW5UftUrAnvJkr6769D29tF7Of79gUjdQHS_TkF5A@xxxxxxxxxxxxxx/
https://lore.kernel.org/lkml/CAHk-=wgy8p4is8ApEQCT5NS7XFb+NXeo-TKz7jRRZVksLLBSrQ@xxxxxxxxxxxxxx/

> I have not found this on the coding-style.
> https://www.kernel.org/doc/html/latest/process/coding-style.html

Feel free to update the documentation.

> > > > > +		phy_exit(k1->phy[i]);

-- 
With Best Regards,
Andy Shevchenko