linux-kernel - Re: [PATCH v2 3/6] clk: qcom: gdsc: Add set and get hwmode callbacks to switch GDSC mode

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Date:   Wed, 16 Aug 2023 19:55:33 +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>,
        Pavel 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,
        Jagadeesh Kona <quic_jkona@...cinc.com>
Subject: Re: [PATCH v2 3/6] clk: qcom: gdsc: Add set and get hwmode callbacks
 to switch GDSC mode

On 16.08.2023 16:57, Abel Vesa wrote:
> From: Jagadeesh Kona <quic_jkona@...cinc.com>
> 
> Add support for set and get hwmode callbacks to switch the GDSC between
> SW and HW modes. Currently, the GDSC is moved to HW control mode
> using HW_CTRL flag and if this flag is present, GDSC is moved to HW
> mode as part of GDSC enable itself. The intention is to keep the
> HW_CTRL flag functionality as is, since many older chipsets still use
> this flag.
> 
> Introduce a new HW_CTRL_TRIGGER flag to switch the GDSC back and forth
> between HW/SW modes dynamically at runtime. If HW_CTRL_TRIGGER flag is
> present, register set_hwmode_dev callback to switch the GDSC mode which
> can be invoked from consumer drivers using dev_pm_genpd_set_hwmode
> function. Unlike HW_CTRL flag, HW_CTRL_TRIGGER won't move the GDSC to HW
> control mode as part of GDSC enable itself, GDSC will be moved to HW
> control mode only when consumer driver explicity calls
> dev_pm_genpd_set_hwmode to switch to HW mode. Also add the
> dev_pm_genpd_get_hwmode to allow the consumers to read the actual
> HW/SW mode from hardware.
> 
> Signed-off-by: Jagadeesh Kona <quic_jkona@...cinc.com>
> Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
> ---
>  drivers/clk/qcom/gdsc.c | 32 ++++++++++++++++++++++++++++++++
>  drivers/clk/qcom/gdsc.h |  1 +
>  2 files changed, 33 insertions(+)
> 
> diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
> index 5358e28122ab..3e4a721f1605 100644
> --- a/drivers/clk/qcom/gdsc.c
> +++ b/drivers/clk/qcom/gdsc.c
> @@ -363,6 +363,34 @@ static int gdsc_disable(struct generic_pm_domain *domain)
>  	return 0;
>  }
>  
> +static int gdsc_set_mode(struct generic_pm_domain *domain, struct device *dev, bool mode)
> +{
> +	struct gdsc *sc = domain_to_gdsc(domain);
> +
> +	if (sc->rsupply && !regulator_is_enabled(sc->rsupply)) {
> +		pr_err("Cannot set mode while parent is disabled\n");
> +		return -EIO;
> +	}
> +
> +	return gdsc_hwctrl(sc, mode);
> +}
> +
> +static bool gdsc_get_mode(struct generic_pm_domain *domain, struct device *dev)
s/mode/hwmode would probably be more descriptive for returning true/false

Konrad