linux-kernel - Re: [PATCH v3 3/4] OPP: Add support of "opp-microwatt" for advanced EM registration

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Message-ID: <eb49beb7-584d-152d-0c61-bad66056505c@arm.com>
Date:   Thu, 24 Feb 2022 09:43:52 +0000
From:   Lukasz Luba <lukasz.luba@....com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     linux-kernel@...r.kernel.org, dietmar.eggemann@....com,
        rafael@...nel.org, daniel.lezcano@...aro.org, nm@...com,
        sboyd@...nel.org, mka@...omium.org, dianders@...omium.org,
        robh+dt@...nel.org, devicetree@...r.kernel.org,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH v3 3/4] OPP: Add support of "opp-microwatt" for advanced
 EM registration



On 2/24/22 09:42, Viresh Kumar wrote:
> On 24-02-22, 09:33, Lukasz Luba wrote:
>> On 2/24/22 09:13, Viresh Kumar wrote:
>>> On 24-02-22, 08:11, Lukasz Luba wrote:
>>>> diff --git a/drivers/opp/of.c b/drivers/opp/of.c
> 
>>>> +static bool _of_has_opp_microwatt_property(struct device *dev)
>>>> +{
>>>> +	unsigned long power, freq = 0;
>>>> +	struct dev_pm_opp *opp;
>>>> +
>>>> +	/* Check if at least one OPP has needed property */
>>>> +	opp = dev_pm_opp_find_freq_ceil(dev, &freq);
>>>> +	if (IS_ERR(opp))
>>>> +		return false;
>>>> +
>>>> +	power = dev_pm_opp_get_power(opp);
>>>> +	dev_pm_opp_put(opp);
>>>> +	if (!power)
>>>
>>> Instead of this heavy stuff, just pick the first OPP from the opp
>>> table and see its power-value.
>>
>> It is the first opp: freq=0.
>> You mean by parsing the the DT node instead, like I had in v2 version?
> 
> No, I was thinking if you can simply do:
> 
> opp = list_first_entry(&opp_table->opp_list, struct dev_pm_opp, node);
> 
> But that requires locking, etc as well. So maybe this is fine.
>   

OK, so I'll leave it as is now.

Thank you for the comments. I'll work on v4