linux-kernel - Re: [PATCH 3/3] i2c: i2c-qcom-geni: Add support for 'assigned-performance-states'

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Date:   Mon, 18 Jan 2021 11:06:10 +0530
From:   Rajendra Nayak <rnayak@...eaurora.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Roja Rani Yarubandi <rojay@...eaurora.org>,
        ulf.hansson@...aro.org, viresh.kumar@...aro.org
Cc:     robh+dt@...nel.org, wsa@...nel.org, swboyd@...omium.org,
        dianders@...omium.org, saiprakash.ranjan@...eaurora.org,
        mka@...omium.org, akashast@...eaurora.org,
        msavaliy@....qualcomm.com, parashar@...eaurora.org,
        linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        agross@...nel.org, linux-i2c@...r.kernel.org
Subject: Re: [PATCH 3/3] i2c: i2c-qcom-geni: Add support for
 'assigned-performance-states'


On 1/15/2021 8:13 PM, Bjorn Andersson wrote:
> On Thu 24 Dec 05:12 CST 2020, Roja Rani Yarubandi wrote:
> 
>> @@ -629,6 +658,16 @@ static int __maybe_unused geni_i2c_runtime_suspend(struct device *dev)
>>   	struct geni_i2c_dev *gi2c = dev_get_drvdata(dev);
>>   
>>   	disable_irq(gi2c->irq);
>> +
>> +	/* Drop the assigned performance state */
>> +	if (gi2c->assigned_pstate) {
>> +		ret = dev_pm_genpd_set_performance_state(dev, 0);
>> +		if (ret) {
>> +			dev_err(dev, "Failed to set performance state\n");
>> +			return ret;
>> +		}
>> +	}
>> +
> 
> Ulf, Viresh, I think we discussed this at the time of introducing the
> performance states.
> 
> The client's state does not affect if its performance_state should
> be included in the calculation of the aggregated performance_state, so
> each driver that needs to keep some minimum performance state needs to
> have these two snippets.
> 
> Would it not make sense to on enable/disable re-evaluate the
> performance_state and potentially reconfigure the hardware
> automatically?

I agree, this will be repeated across multiple drivers which would
need some minimal vote while they are active, handling this during
genpd enable/disable in genpd core makes sense.

> 
> Regards,
> Bjorn
> 
>>   	ret = geni_se_resources_off(&gi2c->se);
>>   	if (ret) {
>>   		enable_irq(gi2c->irq);
>> @@ -654,6 +693,16 @@ static int __maybe_unused geni_i2c_runtime_resume(struct device *dev)
>>   	if (ret)
>>   		return ret;
>>   
>> +	/* Set the assigned performance state */
>> +	if (gi2c->assigned_pstate) {
>> +		ret = dev_pm_genpd_set_performance_state(dev,
>> +							 gi2c->assigned_pstate);
>> +		if (ret) {
>> +			dev_err(dev, "Failed to set performance state\n");
>> +			return ret;
>> +		}
>> +	}
>> +
>>   	enable_irq(gi2c->irq);
>>   	gi2c->suspended = 0;
>>   	return 0;
>> -- 
>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
>> of Code Aurora Forum, hosted by The Linux Foundation
>>

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation