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

[Rafael J. Wysocki]

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?