linux-kernel - Re: [PATCH 2/2] clk: qcom: gdsc: Add support for set_hwmode

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Message-ID: <e94f187e-e444-d18d-eba9-b9a699abdb95@quicinc.com>
Date:   Mon, 10 Jul 2023 09:40:14 +0530
From:   Taniya Das <quic_tdas@...cinc.com>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>,
        Abel Vesa <abel.vesa@...aro.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        "Kevin Hilman" <khilman@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        "avel Machek" <pavel@....cz>, Len Brown <len.brown@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Bjorn Andersson <andersson@...nel.org>,
        "Andy Gross" <agross@...nel.org>,
        Mike Turquette <mturquette@...libre.com>,
        "Stephen Boyd" <sboyd@...nel.org>,
        Taniya Das <tdas@....qualcomm.com>
CC:     <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH 2/2] clk: qcom: gdsc: Add support for set_hwmode_dev

Hi Abel,

Thanks for the patch.

On 6/28/2023 10:48 PM, Konrad Dybcio wrote:
> On 28.06.2023 12:56, Abel Vesa wrote:
>> Implement the GDSC specific genpd set_hwmode_dev callback in order to
>> switch the HW control on or off. For any GDSC that supports HW control
>> set this callback in order to allow its consumers to control it.
>>
>> Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
>> ---
> This still does nothing to prevent the HW_CTRL state being changed in
> init, enable and disable functions.
> 
> Konrad
>>   drivers/clk/qcom/gdsc.c | 22 ++++++++++++++++++++++
>>   1 file changed, 22 insertions(+)
>>
>> diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
>> index 5358e28122ab..9a04bf2e4379 100644
>> --- a/drivers/clk/qcom/gdsc.c
>> +++ b/drivers/clk/qcom/gdsc.c
>> @@ -314,6 +314,26 @@ static int gdsc_enable(struct generic_pm_domain *domain)
>>   	return 0;
>>   }
>>   
>> +static int gdsc_set_hwmode_dev(struct generic_pm_domain *domain,
>> +			       struct device *dev, bool enable)
>> +{
>> +	int ret = gdsc_hwctrl(domain_to_gdsc(domain), enable);
>> +
>> +	if (ret)
>> +		goto out;
>> +
>> +	/*
>> +	 * Wait for the GDSC to go through a power down and
>> +	 * up cycle.  In case there is a status polling going on
>> +	 * before the power cycle is completed it might read an
>> +	 * wrong status value.
>> +	 */
>> +	udelay(1);
>> +
>> +out:
>> +	return ret;
>> +}
>> +
>>   static int gdsc_disable(struct generic_pm_domain *domain)
>>   {
>>   	struct gdsc *sc = domain_to_gdsc(domain);
>> @@ -451,6 +471,8 @@ static int gdsc_init(struct gdsc *sc)
>>   		sc->pd.power_off = gdsc_disable;
>>   	if (!sc->pd.power_on)
>>   		sc->pd.power_on = gdsc_enable;
>> +	if (sc->flags & HW_CTRL)
>> +		sc->pd.set_hwmode_dev = gdsc_set_hwmode_dev;
>>   
We do not want to move to SW mode without consumers wanting to move to 
this mode.

We want a new flag for the consumers wanting to move to this mode. The 
mode in which the GDSC would be enabled would be in SW mode only.
+	if (sc->flags & HW_CTRL_TRIGGER) {
+		sc->pd.set_hwmode_dev = gdsc_set_mode;
+	}
+

>>   	ret = pm_genpd_init(&sc->pd, NULL, !on);
>>   	if (ret)

-- 
Thanks & Regards,
Taniya Das.