linux-kernel - Re: [PATCH] cpufreq: qcom-hw: Use optional irq API

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Message-ID: <76b103ec-7034-e6c1-1ab4-174cf16f9fc8@linaro.org>
Date:   Wed, 17 Nov 2021 21:55:17 -0500
From:   Thara Gopinath <thara.gopinath@...aro.org>
To:     Stephen Boyd <swboyd@...omium.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH] cpufreq: qcom-hw: Use optional irq API

Hello Stephen,

Thanks for the patch

On 11/16/21 9:03 PM, Stephen Boyd wrote:
> Use platform_get_irq_optional() to avoid a noisy error message when the
> irq isn't specified. The irq is definitely optional given that we only
> care about errors that are -EPROBE_DEFER here.
> 
> Cc: Thara Gopinath <thara.gopinath@...aro.org>
> Signed-off-by: Stephen Boyd <swboyd@...omium.org>
> ---
>   drivers/cpufreq/qcom-cpufreq-hw.c | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index a2be0df7e174..b442d4983a22 100644
> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> @@ -382,9 +382,11 @@ static int qcom_cpufreq_hw_lmh_init(struct cpufreq_policy *policy, int index)
>   	 * Look for LMh interrupt. If no interrupt line is specified /
>   	 * if there is an error, allow cpufreq to be enabled as usual.
>   	 */
> -	data->throttle_irq = platform_get_irq(pdev, index);
> -	if (data->throttle_irq <= 0)
> -		return data->throttle_irq == -EPROBE_DEFER ? -EPROBE_DEFER : 0;
> +	data->throttle_irq = platform_get_irq_optional(pdev, index);
> +	if (data->throttle_irq == -ENXIO)
> +		return 0;
> +	if (data->throttle_irq < 0)
> +		return data->throttle_irq;

Here the idea is to return only -EPROBE_DEFER error. Else return a 0 , 
so that cpufreq is enabled even if lmh interrupt is inaccessible. The 
above check returns errors other than -EPROBE_DEFER as well. So I would 
say make irq optional and keep the below check

if (data->throttle_irq <= 0)
	return data->throttle_irq == -EPROBE_DEFER ? -EPROBE_DEFER : 0;

>   
>   	data->cancel_throttle = false;
>   	data->policy = policy;
> 
> base-commit: fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf
> 

-- 
Warm Regards
Thara (She/Her/Hers)