linux-kernel - Re: [PATCH 3/5] cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support

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Date:   Fri, 18 Jun 2021 13:16:38 -0500
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Thara Gopinath <thara.gopinath@...aro.org>
Cc:     agross@...nel.org, rui.zhang@...el.com, daniel.lezcano@...aro.org,
        viresh.kumar@...aro.org, rjw@...ysocki.net, robh+dt@...nel.org,
        linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH 3/5] cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support

On Tue 08 Jun 17:29 CDT 2021, Thara Gopinath wrote:
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
[..]
> @@ -305,6 +383,8 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>  
>  	index = args.args[0];
>  
> +	lmh_mitigation_enabled = of_property_read_bool(pdev->dev.of_node, "qcom,support-lmh");

Rather than adding a new interrupt _and_ a flag to tell the driver that
this new interrupt should be used, wouldn't it be sufficient to just see
if the interrupt is specified?

> +
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, index);
>  	if (!res) {
>  		dev_err(dev, "failed to get mem resource %d\n", index);
> @@ -329,6 +409,11 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>  		goto unmap_base;
>  	}
>  
> +	if (!alloc_cpumask_var(&data->cpus, GFP_KERNEL)) {
> +		ret = -ENOMEM;
> +		goto unmap_base;
> +	}
> +
>  	data->soc_data = of_device_get_match_data(&pdev->dev);
>  	data->base = base;
>  	data->res = res;
> @@ -347,6 +432,7 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>  		goto error;
>  	}
>  
> +	cpumask_copy(data->cpus, policy->cpus);
>  	policy->driver_data = data;
>  
>  	ret = qcom_cpufreq_hw_read_lut(cpu_dev, policy);
> @@ -370,6 +456,20 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
>  			dev_warn(cpu_dev, "failed to enable boost: %d\n", ret);
>  	}
>  
> +	if (lmh_mitigation_enabled) {
> +		data->lmh_dcvs_irq = platform_get_irq(pdev, index);
> +		if (data->lmh_dcvs_irq < 0) {

This will be -ENXIO if the interrupt isn't specified and <0 for other
errors, so you should be able to distinguish the two failure cases.

Regards,
Bjorn

> +			ret = data->lmh_dcvs_irq;
> +			goto error;
> +		}
> +		ret = devm_request_irq(dev, data->lmh_dcvs_irq, qcom_lmh_dcvs_handle_irq,
> +				       0, "dcvsh-irq", data);
> +		if (ret) {
> +			dev_err(dev, "Error %d registering irq %x\n", ret, data->lmh_dcvs_irq);
> +			goto error;
> +		}
> +		INIT_DEFERRABLE_WORK(&data->lmh_dcvs_poll_work, qcom_lmh_dcvs_poll);
> +	}
>  	return 0;
>  error:
>  	kfree(data);
> -- 
> 2.25.1
>