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

From: Sumit Gupta

Date: Tue Jan 20 2026 - 09:57:24 EST


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);
--
2.34.1