Re: [PATCH v7 1/4] soc: mediatek: Refine scpsys to support multiple platform

[Matthias Brugger]

On 12/07/16 05:34, James Liao wrote:
> Hi Matthias,
>
> On Mon, 2016-07-11 at 15:10 +0200, Matthias Brugger wrote:
> > On 11/07/16 10:56, James Liao wrote:
> >
> > [...]
> >
> > > > > > > @@ -467,28 +386,54 @@ static int scpsys_probe(struct platform_device *pdev)
> > > > > > >    			if (PTR_ERR(scpd->supply) == -ENODEV)
> > > > > > >    				scpd->supply = NULL;
> > > > > > >    			else
> > > > > > > -				return PTR_ERR(scpd->supply);
> > > > > > > +				return ERR_CAST(scpd->supply);
> > > > > > >    		}
> > > > > > >    	}
> > > > > > >
> > > > > > > -	pd_data->num_domains = NUM_DOMAINS;
> > > > > > > +	pd_data->num_domains = num;
> > > > > > >
> > > > > > > -	for (i = 0; i < NUM_DOMAINS; i++) {
> > > > > > > +	init_clks(pdev, clk);
> > > > > > > +
> > > > > > > +	for (i = 0; i < num; i++) {
> > > > > > >    		struct scp_domain *scpd = &scp->domains[i];
> > > > > > >    		struct generic_pm_domain *genpd = &scpd->genpd;
> > > > > > >    		const struct scp_domain_data *data = &scp_domain_data[i];
> > > > > > >
> > > > > > > +		for (j = 0; j < MAX_CLKS && data->clk_id[j]; j++) {
> > > > > > > +			struct clk *c = clk[data->clk_id[j]];
> > > > > > > +
> > > > > > > +			if (IS_ERR(c)) {
> > > > > > > +				dev_err(&pdev->dev, "%s: clk unavailable\n",
> > > > > > > +					data->name);
> > > > > > > +				return ERR_CAST(c);
> > > > > > > +			}
> > > > > > > +
> > > > > > > +			scpd->clk[j] = c;
> > > > > >
> > > > > > Put this in the else branch. Apart from that is there any reason you
> > > > >
> > > > > Do you mean to change like this?
> > > > >
> > > > > 	if (IS_ERR(c)) {
> > > > > 		...
> > > > > 		return ERR_CAST(c);
> > > > > 	} else {
> > > > > 		scpd->clk[j] = c;
> > > > > 	}
> > > > >
> > > > > checkpatch.pl will warn for above code due to it returns in 'if' branch.
> > > >
> > > > I tried that on top of next-20160706 and it checkpatch didn't throw any
> > > > warning. Which kernel version are based on?
> > >
> > > I don't remember which version of checkpatch warn on this pattern. This
> > > patch series develop across several kernel versions.
> >
> > We as the kernel community develop against master or linux-next. We only
> > care about older kernel version in the sense that we intent hard not to
> > break any userspace/kernel or firmware/kernel interfaces. Apart from
> > that it's up to every individual to backport patches from mainline
> > kernel to his respective version. But that's nothing the community as a
> > hole can take care of.
> >
> > > So do you prefer to put "scpd->clk[j] = c;" into 'else' branch?
> >
> > Yes please :)
>
> Yingjoe had tested in the latest checkpatch.pl and it showed checkpatch
> warn on the else-branch. He had replied the results in previous email.

Yes you are right. Not sure what I was testing. Sorry for that.

> > > > > > moved the for up in the function? If not, I would prefer not to move it,
> > > > > > to make it easier to read the diff.
> > > > >
> > > > > The new 'for' block are far different from original one. And I think
> > > > > it's easy to read if we keep simple assign statements in the same block.
> > > >
> > > > It's different in the sense that it checks if struct clk *c is an error.
> > > > I don't see the reason why we need to move it up in the file.
> > > > It's not too important but I would prefer not to move it if there is no
> > > > reason.
> > >
> > > I think I may misunderstand your comments. Which 'for' block did you
> > > mention for? 'for (i = 0; i < num ...' or 'for (j = 0; j < MAX_CLKS
> > > && ...' ?
> > >
> > > The 'for(i)' exists in original code, this patch just change its counter
> > > from 'NUM_DOMAINS' to 'num'. The 'for(j)' is a new for-block, so it was
> > > not moved from other blocks.
> >
> > for (j = 0; j < MAX_CLKS... is present in the actual scpsys_probe in
> > linux-next (line 485 as of today). This patch moves this for a few lines
> > up, to be precise before executing this code sequence:
> > <code>
> > pd_data->domains[i] = genpd;
> > scpd->scp = scp;
> >
> > scpd->data = data;
> > </code>
> >
> > AFAIK there is no reason to do so. It adds unnecessary complexity to the
> > patch. So please fix this together with the other comments you got.
>
> I see. So you prefer to put the for(j < MAX_CLKS) after 'scpd->data =
> data' right? I can change it in next patch.

Ok, thanks.

Regards,
Matthias