linux-kernel - [PATCH v4 1/8] cpufreq: CPPC: Add generic helpers for sysfs show/store

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Message-ID: <20251105113844.4086250-2-sumitg@nvidia.com>
Date: Wed, 5 Nov 2025 17:08:37 +0530
From: Sumit Gupta <sumitg@...dia.com>
To: <rafael@...nel.org>, <viresh.kumar@...aro.org>, <lenb@...nel.org>,
	<robert.moore@...el.com>, <corbet@....net>, <pierre.gondois@....com>,
	<zhenglifeng1@...wei.com>, <rdunlap@...radead.org>, <ray.huang@....com>,
	<gautham.shenoy@....com>, <mario.limonciello@....com>, <perry.yuan@....com>,
	<ionela.voinescu@....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>
CC: <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: [PATCH v4 1/8] cpufreq: CPPC: Add generic helpers for sysfs show/store

Add generic show/store helper functions for u64 sysfs attributes:
- cppc_cpufreq_sysfs_show_u64()
- cppc_cpufreq_sysfs_store_u64()

Refactor auto_act_window and energy_performance_preference_val
attributes to use these helpers, eliminating code duplication.

No functional changes.

Signed-off-by: Sumit Gupta <sumitg@...dia.com>
---
 drivers/cpufreq/cppc_cpufreq.c | 57 ++++++++++++----------------------
 1 file changed, 19 insertions(+), 38 deletions(-)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index e23d9abea135..cf3ed6489a4f 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -832,72 +832,53 @@ 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(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)
+static ssize_t show_auto_act_window(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");
+	return cppc_cpufreq_sysfs_show_u64(policy->cpu, cppc_get_auto_act_window, buf);
+}
 
-	if (ret)
-		return ret;
+static ssize_t store_auto_act_window(struct cpufreq_policy *policy, const char *buf, size_t count)
+{
+	return cppc_cpufreq_sysfs_store_u64(policy->cpu, cppc_set_auto_act_window, buf, count);
+}
 
-	return sysfs_emit(buf, "%llu\n", val);
+static ssize_t show_energy_performance_preference_val(struct cpufreq_policy *policy, char *buf)
+{
+	return cppc_cpufreq_sysfs_show_u64(policy->cpu, cppc_get_epp_perf, buf);
 }
 
 static ssize_t store_energy_performance_preference_val(struct cpufreq_policy *policy,
 						       const char *buf, size_t count)
 {
-	u64 val;
-	int ret;
-
-	ret = kstrtou64(buf, 0, &val);
-	if (ret)
-		return ret;
-
-	ret = cppc_set_epp(policy->cpu, val);
-	if (ret)
-		return ret;
-
-	return count;
+	return cppc_cpufreq_sysfs_store_u64(policy->cpu, cppc_set_epp, buf, count);
 }
 
 cpufreq_freq_attr_ro(freqdomain_cpus);
-- 
2.34.1