Re: [PATCH v6 1/9] cpufreq: CPPC: Add generic helpers for sysfs show/store

[Sumit Gupta]

On 27/01/26 21:54, Rafael J. Wysocki wrote:
> External email: Use caution opening links or attachments
>
>
> On Tue, Jan 20, 2026 at 3:57 PM Sumit Gupta <sumitg@xxxxxxxxxx> wrote:
> > Add generic helper functions for u64 sysfs attributes that follow the
> > common pattern of calling CPPC get/set APIs:
> > - cppc_cpufreq_sysfs_show_u64(): reads value and handles -EOPNOTSUPP
> > - cppc_cpufreq_sysfs_store_u64(): parses input and calls set function
> >
> > Add CPPC_CPUFREQ_ATTR_RW_U64() macro to generate show/store functions
> > using these helpers, reducing boilerplate for simple attributes.
> >
> > Convert auto_act_window and energy_performance_preference_val to use
> > the new macro.
> >
> > No functional changes.
> >
> > Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx>
> > ---
> >   drivers/cpufreq/cppc_cpufreq.c | 69 ++++++++++++----------------------
> >   1 file changed, 25 insertions(+), 44 deletions(-)
> >
> > diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> > index 36e8a75a37f1..c95dcd7719c3 100644
> > --- a/drivers/cpufreq/cppc_cpufreq.c
> > +++ b/drivers/cpufreq/cppc_cpufreq.c
> > @@ -863,73 +863,54 @@ static ssize_t store_auto_select(struct cpufreq_policy *policy,
> >          return count;
> >   }
> >
> > -static ssize_t show_auto_act_window(struct cpufreq_policy *policy, char *buf)
> > +static ssize_t cppc_cpufreq_sysfs_show_u64(unsigned int cpu,
> > +                                          int (*get_func)(int, u64 *),
> > +                                          char *buf)
> >   {
> >          u64 val;
> > -       int ret;
> > -
> > -       ret = cppc_get_auto_act_window(policy->cpu, &val);
> > +       int ret = get_func((int)cpu, &val);
> >
> > -       /* show "<unsupported>" when this register is not supported by cpc */
> >          if (ret == -EOPNOTSUPP)
> >                  return sysfs_emit(buf, "<unsupported>\n");
> > -
> >          if (ret)
> >                  return ret;
> >
> >          return sysfs_emit(buf, "%llu\n", val);
> >   }
> >
> > -static ssize_t store_auto_act_window(struct cpufreq_policy *policy,
> > -                                    const char *buf, size_t count)
> > +static ssize_t cppc_cpufreq_sysfs_store_u64(unsigned int cpu,
> > +                                           int (*set_func)(int, u64),
> > +                                           const char *buf, size_t count)
> >   {
> > -       u64 usec;
> > +       u64 val;
> >          int ret;
> >
> > -       ret = kstrtou64(buf, 0, &usec);
> > +       ret = kstrtou64(buf, 0, &val);
> >          if (ret)
> >                  return ret;
> >
> > -       ret = cppc_set_auto_act_window(policy->cpu, usec);
> > -       if (ret)
> > -               return ret;
> > +       ret = set_func((int)cpu, val);
> >
> > -       return count;
> > +       return ret ? ret : count;
> >   }
> >
> > -static ssize_t show_energy_performance_preference_val(struct cpufreq_policy *policy, char *buf)
> > -{
> > -       u64 val;
> > -       int ret;
> > -
> > -       ret = cppc_get_epp_perf(policy->cpu, &val);
> > -
> > -       /* show "<unsupported>" when this register is not supported by cpc */
> > -       if (ret == -EOPNOTSUPP)
> > -               return sysfs_emit(buf, "<unsupported>\n");
> > -
> > -       if (ret)
> > -               return ret;
> > -
> > -       return sysfs_emit(buf, "%llu\n", val);
> > +#define CPPC_CPUFREQ_ATTR_RW_U64(_name, _get_func, _set_func)          \
> > +static ssize_t show_##_name(struct cpufreq_policy *policy, char *buf)  \
> > +{                                                                      \
> > +       return cppc_cpufreq_sysfs_show_u64(policy->cpu, _get_func, buf);\
> > +}                                                                      \
> > +static ssize_t store_##_name(struct cpufreq_policy *policy,            \
> > +                            const char *buf, size_t count)             \
> > +{                                                                      \
> > +       return cppc_cpufreq_sysfs_store_u64(policy->cpu, _set_func,     \
> > +                                           buf, count);                \
> >   }
> >
> > -static ssize_t store_energy_performance_preference_val(struct cpufreq_policy *policy,
> > -                                                      const char *buf, size_t count)
> > -{
> > -       u64 val;
> > -       int ret;
> > +CPPC_CPUFREQ_ATTR_RW_U64(auto_act_window, cppc_get_auto_act_window,
> > +                        cppc_set_auto_act_window)
> >
> > -       ret = kstrtou64(buf, 0, &val);
> > -       if (ret)
> > -               return ret;
> > -
> > -       ret = cppc_set_epp(policy->cpu, val);
> > -       if (ret)
> > -               return ret;
> > -
> > -       return count;
> > -}
> > +CPPC_CPUFREQ_ATTR_RW_U64(energy_performance_preference_val,
> > +                        cppc_get_epp_perf, cppc_set_epp)
> >
> >   cpufreq_freq_attr_ro(freqdomain_cpus);
> >   cpufreq_freq_attr_rw(auto_select);
> > --
> It looks like this patch could be applied independently of the other
> patches in the series.
>
> Do you want me to do so?

Yes, this patch is independent and can be applied.

Thank you,
Sumit Gupta