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

[Bryan O'Donoghue]

On 24/08/2023 15:12, Heikki Krogerus wrote:
> On Thu, Aug 24, 2023 at 10:32:03AM +0800, Hui Liu via B4 Relay wrote:
> > From: Hui Liu <quic_huliu@xxxxxxxxxxx>
> >
> > Check regulator enable status before disabling it to avoid
> > unbalanced regulator disable warnings.
> >
> > Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > Fixes: a4422ff22142 ("usb: typec: qcom: Add Qualcomm PMIC Type-C driver")
> > Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
> > Signed-off-by: Hui Liu <quic_huliu@xxxxxxxxxxx>
> > ---
> > Changes in v2:
> > - Add Fixes tag
> > - Link to v1: https://lore.kernel.org/r/20230823-qcom-tcpc-v1-1-fa81a09ca056@xxxxxxxxxxx
> > ---
> >   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,

I don't see why not.

The code would look neater that way too.

Can you give it a try Hui ?

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 4e1b846627d20..d29f9506e5f12 100644
--- a/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec_pdphy.c
+++ b/drivers/usb/typec/tcpm/qcom/qcom_pmic_typec_pdphy.c
@@ -383,10 +383,6 @@ static int qcom_pmic_typec_pdphy_enable(struct 
pmic_typec_pdphy *pmic_typec_pdph
        struct device *dev = pmic_typec_pdphy->dev;
        int ret;

-       ret = regulator_enable(pmic_typec_pdphy->vdd_pdphy);
-       if (ret)
-               return ret;
-
        /* PD 2.0, DR=TYPEC_DEVICE, PR=TYPEC_SINK */
        ret = regmap_update_bits(pmic_typec_pdphy->regmap,
                                 pmic_typec_pdphy->base + 
USB_PDPHY_MSG_CONFIG_REG,
@@ -424,8 +420,6 @@ 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);
-
        return ret;
 }

@@ -449,6 +443,10 @@ int qcom_pmic_typec_pdphy_start(struct 
pmic_typec_pdphy *pmic_typec_pdphy,
        int i;
        int ret;

+       ret = regulator_enable(pmic_typec_pdphy->vdd_pdphy);
+       if (ret)
+               return ret;
+
        pmic_typec_pdphy->tcpm_port = tcpm_port;

        ret = pmic_typec_pdphy_reset(pmic_typec_pdphy);
@@ -469,6 +467,8 @@ void qcom_pmic_typec_pdphy_stop(struct 
pmic_typec_pdphy *pmic_typec_pdphy)
                disable_irq(pmic_typec_pdphy->irq_data[i].irq);

        qcom_pmic_typec_pdphy_reset_on(pmic_typec_pdphy);
+
+       regulator_disable(pmic_typec_pdphy->vdd_pdphy);
 }

---
bod