linux-kernel - Re: [PATCH v5 01/11] cpufreq: CPPC: Add generic helpers for sysfs show/store

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Message-ID: <dbbbdb83-24d4-465e-99bb-689cd6e37460@huawei.com>
Date: Thu, 25 Dec 2025 11:41:19 +0800
From: "zhenglifeng (A)" <zhenglifeng1@...wei.com>
To: Sumit Gupta <sumitg@...dia.com>, <rafael@...nel.org>,
	<viresh.kumar@...aro.org>, <lenb@...nel.org>, <robert.moore@...el.com>,
	<corbet@....net>, <pierre.gondois@....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>
Subject: Re: [PATCH v5 01/11] cpufreq: CPPC: Add generic helpers for sysfs
 show/store

On 2025/12/23 20:12, Sumit Gupta wrote:
> 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.

How about adding a macro to generate show_xxx and store_xxx in one line?

Just a suggestion.

> 
> No functional changes.
> 
> Signed-off-by: Sumit Gupta <sumitg@...dia.com>
> ---
>  drivers/cpufreq/cppc_cpufreq.c | 71 +++++++++++++++-------------------
>  1 file changed, 31 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index 9eac77c4f294..7c26ce554e29 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -831,72 +831,63 @@ 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)
> +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");
> -
> -	if (ret)
> -		return ret;
> -
> -	return sysfs_emit(buf, "%llu\n", val);
> +	return cppc_cpufreq_sysfs_show_u64(policy->cpu,
> +					   cppc_get_auto_act_window, buf);
>  }
>  
> -static ssize_t store_energy_performance_preference_val(struct cpufreq_policy *policy,
> -						       const char *buf, size_t count)
> +static ssize_t store_auto_act_window(struct cpufreq_policy *policy,
> +				     const char *buf, size_t count)
>  {
> -	u64 val;
> -	int ret;
> -
> -	ret = kstrtou64(buf, 0, &val);
> -	if (ret)
> -		return ret;
> +	return cppc_cpufreq_sysfs_store_u64(policy->cpu,
> +					    cppc_set_auto_act_window,
> +					    buf, count);
> +}
>  
> -	ret = cppc_set_epp(policy->cpu, val);
> -	if (ret)
> -		return ret;
> +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);
> +}
>  
> -	return count;
> +static ssize_t
> +store_energy_performance_preference_val(struct cpufreq_policy *policy,
> +					const char *buf, size_t count)
> +{
> +	return cppc_cpufreq_sysfs_store_u64(policy->cpu, cppc_set_epp,
> +					    buf, count);
>  }
>  
>  cpufreq_freq_attr_ro(freqdomain_cpus);