[PATCH v7 12/14] cpufreq: Add Kryo CPU scaling driver

[ilialin at codeaurora.org]

> -----Original Message-----
> From: ilialin at codeaurora.org <ilialin at codeaurora.org>
> Sent: Thursday, May 17, 2018 10:51
> To: 'Viresh Kumar' <viresh.kumar at linaro.org>; 'Amit Kucheria'
> <amit.kucheria at linaro.org>
> Cc: 'Michael Turquette' <mturquette at baylibre.com>; 'sboyd at kernel.org'
> <sboyd at kernel.org>; 'Rob Herring' <robh at kernel.org>; 'Mark Rutland'
> <mark.rutland at arm.com>; 'nm at ti.com' <nm at ti.com>;
> 'lgirdwood at gmail.com' <lgirdwood at gmail.com>; 'broonie at kernel.org'
> <broonie at kernel.org>; 'Andy Gross' <andy.gross at linaro.org>; 'David Brown'
> <david.brown at linaro.org>; 'catalin.marinas at arm.com'
> <catalin.marinas at arm.com>; 'will.deacon at arm.com'
> <will.deacon at arm.com>; 'Rafael J. Wysocki' <rjw at rjwysocki.net>; 'linux-
> clk at vger.kernel.org' <linux-clk at vger.kernel.org>;
> 'devicetree at vger.kernel.org' <devicetree at vger.kernel.org>; 'LKML' <linux-
> kernel at vger.kernel.org>; 'Linux PM list' <linux-pm at vger.kernel.org>;
'linux-
> arm-msm at vger.kernel.org' <linux-arm-msm at vger.kernel.org>; 'linux-
> soc at vger.kernel.org' <linux-soc at vger.kernel.org>; 'lakml' <linux-arm-
> kernel at lists.infradead.org>; 'Rajendra Nayak' <rnayak at codeaurora.org>;
> 'nicolas.dechesne at linaro.org' <nicolas.dechesne at linaro.org>;
> 'celster at codeaurora.org' <celster at codeaurora.org>;
> 'tfinkel at codeaurora.org' <tfinkel at codeaurora.org>
> Subject: RE: [PATCH v7 12/14] cpufreq: Add Kryo CPU scaling driver
> 
> 
> 
> > -----Original Message-----
> > From: Viresh Kumar <viresh.kumar at linaro.org>
> > Sent: Wednesday, May 16, 2018 17:12
> > To: Amit Kucheria <amit.kucheria at linaro.org>
> > Cc: Ilia Lin <ilialin at codeaurora.org>; Michael Turquette
> > <mturquette at baylibre.com>; sboyd at kernel.org; Rob Herring
> > <robh at kernel.org>; Mark Rutland <mark.rutland at arm.com>; nm at ti.com;
> > lgirdwood at gmail.com; broonie at kernel.org; Andy Gross
> > <andy.gross at linaro.org>; David Brown <david.brown at linaro.org>;
> > catalin.marinas at arm.com; will.deacon at arm.com; Rafael J. Wysocki
> > <rjw at rjwysocki.net>; linux-clk at vger.kernel.org;
> > devicetree at vger.kernel.org; LKML <linux-kernel at vger.kernel.org>; Linux
> > PM list <linux-pm at vger.kernel.org>; linux-arm-msm at vger.kernel.org;
> > linux- soc at vger.kernel.org; lakml
> > <linux-arm-kernel at lists.infradead.org>;
> > Rajendra Nayak <rnayak at codeaurora.org>; nicolas.dechesne at linaro.org;
> > celster at codeaurora.org; tfinkel at codeaurora.org
> > Subject: Re: [PATCH v7 12/14] cpufreq: Add Kryo CPU scaling driver
> >
> > On 16-05-18, 16:12, Amit Kucheria wrote:
> > > > +       ret = PTR_ERR_OR_ZERO(opp_temp =
> > > > +
> > dev_pm_opp_set_supported_hw(cpu_dev,&versions,1));
> > > > +       if (0 > ret)
> > >
> > > Any particular reason to prefer this over (ret < 0) that is
> > > generally used? I've seen it used to avoid the == vs. = typos, but
> > > not for other comparisons.
> > >
> > > Suggest sticking to what is commonly used i.e. ret < 0.
> > >
> > > > +               goto free_opp;
> > > > +
> > > > +       cpu_dev = get_cpu_device(GOLD_LEAD);
> > >
> > > Error check cpu_dev here?
> > >
> > > > +       ret = PTR_ERR_OR_ZERO(opp_temp =
> > > > +
> > dev_pm_opp_set_supported_hw(cpu_dev,&versions,1));
> > > > +       if (0 > ret)
> > > > +               goto free_opp;
> >
> > The goto here is wrong
> 
> If we are here, then the first dev_pm_opp_set_supported_hw() succeeded.
> And should be deallocated before exit with error.

My bad. Got you.

> 
> >
> > > > +
> > > > +
> > > > +       ret =
> > PTR_ERR_OR_ZERO(platform_device_register_simple("cpufreq-dt",
> > > > +                                                             -1,
> > > > + NULL, 0));
> > > > +
> > > > +       if (0 == ret)
> > > > +               return 0;
> > > > +
> > > > +free_opp:
> > > > +       dev_pm_opp_put_supported_hw(opp_temp);
> > >
> > > This is not needed because dev_pm_opp_set_supported_hw will free
> > > memory in case of failure. This call in only needed in case of a
> > > successful get.
> >
> > But this is still required for the case where platform device
registration fails.
> >
> > --
> > viresh