iio: adc: rzg2l_adc: Enable runtime PM autosuspend support

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.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://patch.msgid.link/20241206111337.726244-9-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c
index 7da84224a2924901bb9b8a2b3296de995a6ecd05..4191b090ec746ede46d7a88918977298c3aa99dc 100644 (file)
--- a/drivers/iio/adc/rzg2l_adc.c
+++ b/drivers/iio/adc/rzg2l_adc.c
@@ -208,7 +208,8 @@ 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;
 }
 
@@ -373,7 +374,8 @@ 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;
 }
 
@@ -411,6 +413,8 @@ static int rzg2l_adc_probe(struct platform_device *pdev)
                return dev_err_probe(dev, PTR_ERR(adc->presetn),
                                     "failed to get/deassert presetn\n");
 
+       pm_runtime_set_autosuspend_delay(dev, 300);
+       pm_runtime_use_autosuspend(dev);
        ret = devm_pm_runtime_enable(dev);
        if (ret)
                return ret;