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

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Message-ID: <42b1167d-da60-f6c3-67b6-3f6857327396@linaro.org>
Date:   Wed, 28 Jun 2023 19:18:45 +0200
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     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

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