On Tue, 3 Dec 2024 13:13:07 +0200 Claudiu <claudiu.beznea@xxxxxxxxx> wrote: > From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx> > > Enable runtime PM autosuspend support for the rzg2l_adc driver. With this > change, consecutive conversion requests will no longer cause the device to > be runtime-enabled/disabled after each request. Instead, the device will > transition based on the delay configured by the user. > > This approach reduces the frequency of hardware register access during > runtime PM suspend/resume cycles, thereby saving CPU cycles. The default > autosuspend delay is set to zero to maintain the previous driver behavior. Unless you have a weird user who is polling slow enough to not trigger autosuspend with a non zero period, but is still saving power I'm not convinced anyone will notice if you just enable this for a sensible autosuspend delay. There will of course be a small increase in power usage for each read but hopefully that is trivial. So I'd not go with a default of 0, though what value makes sense depends on the likely usecase + how much power is saved by going to sleep. If you really want to keep 0 I don't mind that much, just seems odd! Jonathan > > Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx> > --- > drivers/iio/adc/rzg2l_adc.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c > index eed2944bd98d..fda8b42ded81 100644 > --- a/drivers/iio/adc/rzg2l_adc.c > +++ b/drivers/iio/adc/rzg2l_adc.c > @@ -207,7 +207,8 @@ static int rzg2l_adc_conversion(struct iio_dev *indio_dev, struct rzg2l_adc *adc > rzg2l_adc_start_stop(adc, false); > > rpm_put: > - pm_runtime_put_sync(dev); > + pm_runtime_mark_last_busy(dev); > + pm_runtime_put_autosuspend(dev); > return ret; > } > > @@ -372,7 +373,8 @@ static int rzg2l_adc_hw_init(struct device *dev, struct rzg2l_adc *adc) > rzg2l_adc_writel(adc, RZG2L_ADM(3), reg); > > exit_hw_init: > - pm_runtime_put_sync(dev); > + pm_runtime_mark_last_busy(dev); > + pm_runtime_put_autosuspend(dev); > return ret; > } > > @@ -412,6 +414,9 @@ static int rzg2l_adc_probe(struct platform_device *pdev) > return PTR_ERR(adc->presetn); > } > > + /* Default 0 for power saving. Can be overridden via sysfs. */ > + pm_runtime_set_autosuspend_delay(dev, 0); > + pm_runtime_use_autosuspend(dev); > ret = devm_pm_runtime_enable(dev); > if (ret) > return ret;
