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Message-ID: <6be02e54-dd4a-4d8f-b2ee-291da63b0bf2@nvidia.com>
Date: Wed, 28 Jan 2026 00:31:18 +0530
From: Sumit Gupta <sumitg@...dia.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: viresh.kumar@...aro.org, pierre.gondois@....com, zhenglifeng1@...wei.com,
ionela.voinescu@....com, lenb@...nel.org, robert.moore@...el.com,
corbet@....net, rdunlap@...radead.org, ray.huang@....com,
gautham.shenoy@....com, mario.limonciello@....com, perry.yuan@....com,
zhanjie9@...ilicon.com, linux-pm@...r.kernel.org,
linux-acpi@...r.kernel.org, linux-doc@...r.kernel.org,
acpica-devel@...ts.linux.dev, linux-kernel@...r.kernel.org,
linux-tegra@...r.kernel.org, treding@...dia.com, jonathanh@...dia.com,
vsethi@...dia.com, ksitaraman@...dia.com, sanjayc@...dia.com,
nhartman@...dia.com, bbasu@...dia.com, sumitg@...dia.com
Subject: Re: [PATCH v6 1/9] cpufreq: CPPC: Add generic helpers for sysfs
show/store
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@...dia.com> 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@...dia.com>
>> ---
>> 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
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