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

From: James Liao
Date: Mon Jul 11 2016 - 23:34:32 EST


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.

> >>>> 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.


Best regards,

James