Re: [PATCH v13 5/6] usb: dwc3: qcom: Keep power domain on to retain controller status

[Sandeep Maheswaram (Temp)]

Hi,

On 4/12/2022 2:43 AM, Matthias Kaehlcke wrote:
> On Tue, Apr 12, 2022 at 12:46:53AM +0530, Sandeep Maheswaram wrote:
> > Keep the power domain always on during runtime suspend or if the
> > controller supports wakeup in order to retain controller status
> > and to support wakeup from devices.
> >
> > Signed-off-by: Sandeep Maheswaram <quic_c_sanm@xxxxxxxxxxx>
> > ---
> >   drivers/usb/dwc3/dwc3-qcom.c | 11 ++++++++++-
> >   1 file changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> > index 9804a19..9747be6 100644
> > --- a/drivers/usb/dwc3/dwc3-qcom.c
> > +++ b/drivers/usb/dwc3/dwc3-qcom.c
> > @@ -17,6 +17,7 @@
> >   #include <linux/of_platform.h>
> >   #include <linux/platform_device.h>
> >   #include <linux/phy/phy.h>
> > +#include <linux/pm_domain.h>
> >   #include <linux/usb/of.h>
> >   #include <linux/reset.h>
> >   #include <linux/iopoll.h>
> > @@ -724,6 +725,7 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
> >   	struct resource		*res, *parent_res = NULL;
> >   	int			ret, i;
> >   	bool			ignore_pipe_clk;
> > +	struct generic_pm_domain *genpd;
> nit: I'm not really a fan of gazillions of whitespaces between the type
> and the variable name, but if they are kept all variable names above
> should move a tab to the right. In any case the style in this file isn't
> consistent, so an alternative would be to just get rid of the alignment
> completely.
Okay. Will do it in next version.
> >   	qcom = devm_kzalloc(&pdev->dev, sizeof(*qcom), GFP_KERNEL);
> >   	if (!qcom)
> > @@ -732,6 +734,8 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
> >   	platform_set_drvdata(pdev, qcom);
> >   	qcom->dev = &pdev->dev;
> >   
> > +	genpd = pd_to_genpd(qcom->dev->pm_domain);
> > +
> >   	if (has_acpi_companion(dev)) {
> >   		qcom->acpi_pdata = acpi_device_get_match_data(dev);
> >   		if (!qcom->acpi_pdata) {
> > @@ -839,7 +843,12 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
> >   	if (ret)
> >   		goto interconnect_exit;
> >   
> > -	device_init_wakeup(&pdev->dev, 1);
> > +	genpd->flags |= GENPD_FLAG_RPM_ALWAYS_ON;
> > +
> > +	if (device_may_wakeup(&qcom->dwc3->dev))
> > +		genpd->flags |= GENPD_FLAG_ALWAYS_ON;
> In v12 only GENPD_FLAG_ALWAYS_ON was set, not GENPD_FLAG_RPM_ALWAYS_ON.
> I asked a few times for a change log, in this instance it would be
> useful to explain why GENPD_FLAG_RPM_ALWAYS_ON is now set.
Okay. Will add it in next version.
> > +
> > +	device_init_wakeup(&pdev->dev, device_may_wakeup(&qcom->dwc3->dev));
> device_may_wakeup() isn't an expensive operation, but it's still not nice to
> call it twice in three lines of code. Instead you could do this:
>
> 	if (device_may_wakeup(&qcom->dwc3->dev)) {
> 		genpd->flags |= GENPD_FLAG_ALWAYS_ON;
> 		device_init_wakeup(&pdev->dev, true);
> 	}
Okay. Will do it in next version.