linux-kernel - Re: [PATCH v2] usb: typec: qcom: check regulator enable status before disabling it

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Message-ID: <ZOdlOQ+N2J7jyIEZ@kuha.fi.intel.com>
Date:   Thu, 24 Aug 2023 17:12:09 +0300
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     quic_huliu@...cinc.com
Cc:     Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, quic_fenglinw@...cinc.com,
        subbaram@...cinc.com
Subject: Re: [PATCH v2] usb: typec: qcom: check regulator enable status
 before disabling it

On Thu, Aug 24, 2023 at 10:32:03AM +0800, Hui Liu via B4 Relay wrote:
> From: Hui Liu <quic_huliu@...cinc.com>
> 
> Check regulator enable status before disabling it to avoid
> unbalanced regulator disable warnings.
> 
> Reviewed-by: Guenter Roeck <linux@...ck-us.net>
> Fixes: a4422ff22142 ("usb: typec: qcom: Add Qualcomm PMIC Type-C driver")
> Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@...aro.org>
> Signed-off-by: Hui Liu <quic_huliu@...cinc.com>
> ---
> Changes in v2:
> - Add Fixes tag
> - Link to v1: https://lore.kernel.org/r/20230823-qcom-tcpc-v1-1-fa81a09ca056@quicinc.com
> ---
>  drivers/usb/typec/tcpm/qcom/qcom_pmic_typec_pdphy.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec_pdphy.c b/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec_pdphy.c
> index bb0b8479d80f..ca616b17b5b6 100644
> --- a/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec_pdphy.c
> +++ b/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec_pdphy.c
> @@ -422,7 +422,8 @@ static int qcom_pmic_typec_pdphy_disable(struct pmic_typec_pdphy *pmic_typec_pdp
>  	ret = regmap_write(pmic_typec_pdphy->regmap,
>  			   pmic_typec_pdphy->base + USB_PDPHY_EN_CONTROL_REG, 0);
>  
> -	regulator_disable(pmic_typec_pdphy->vdd_pdphy);
> +	if (regulator_is_enabled(pmic_typec_pdphy->vdd_pdphy))
> +		regulator_disable(pmic_typec_pdphy->vdd_pdphy);

Would it be an option to just enable the regulator in
qcom_pmic_typec_pdphy_start() and disable it in
qcom_pmic_typec_pdphy_stop()?

Now the whole thing looks weird. That regulator is in practice
only disabled and then enabled in one and the same place -
pmic_typec_pdphy_reset(). It's not touched anywhere else. That makes
the above condition confusing to me. I may be missing something.

At least more explanation is needed.

thanks,

-- 
heikki