[PATCH 10/14] iio: adc: rzg2l_adc: Add suspend/resume support

Claudiu
2024-12-03T11:13:49Z

From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

The Renesas RZ/G3S SoC features a power-saving mode where power to most of
the SoC components is turned off, including the ADC IP.

Suspend/resume support has been added to the rzg2l_adc driver to restore
functionality after resuming from this power-saving mode. During suspend,
the ADC resets are asserted, and the ADC is powered down. On resume, the
ADC resets are de-asserted, the hardware is re-initialized, and the ADC
power is restored using the runtime PM APIs.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---
drivers/iio/adc/rzg2l_adc.c | 70 +++++++++++++++++++++++++++++++++++++
1 file changed, 70 insertions(+)

diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c
index f938b0f9a795..634073e7241f 100644
--- a/drivers/iio/adc/rzg2l_adc.c
+++ b/drivers/iio/adc/rzg2l_adc.c
@@ -86,6 +86,7 @@ struct rzg2l_adc {
u16 *last_val;
struct completion completion;
struct mutex lock;
+ bool was_rpm_active;
};

/**
@@ -550,8 +551,77 @@ static int rzg2l_adc_pm_runtime_resume(struct device *dev)
return 0;
}

+static int rzg2l_adc_suspend(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct rzg2l_adc *adc = iio_priv(indio_dev);
+ struct reset_control_bulk_data resets[] = {
+ { .rstc = adc->presetn },
+ { .rstc = adc->adrstn },
+ };
+ int ret;
+
+ if (pm_runtime_suspended(dev)) {
+ adc->was_rpm_active = false;
+ } else {
+ ret = pm_runtime_force_suspend(dev);
+ if (ret)
+ return ret;
+ adc->was_rpm_active = true;
+ }
+
+ ret = reset_control_bulk_assert(ARRAY_SIZE(resets), resets);
+ if (ret)
+ goto rpm_restore;
+
+ return 0;
+
+rpm_restore:
+ if (adc->was_rpm_active)
+ pm_runtime_force_resume(dev);
+
+ return ret;
+}
+
+static int rzg2l_adc_resume(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct rzg2l_adc *adc = iio_priv(indio_dev);
+ struct reset_control_bulk_data resets[] = {
+ { .rstc = adc->adrstn },
+ { .rstc = adc->presetn },
+ };
+ int ret;
+
+ ret = reset_control_bulk_deassert(ARRAY_SIZE(resets), resets);
+ if (ret)
+ return ret;
+
+ if (adc->was_rpm_active) {
+ ret = pm_runtime_force_resume(dev);
+ if (ret)
+ goto resets_restore;
+ }
+
+ ret = rzg2l_adc_hw_init(dev, adc);
+ if (ret)
+ goto rpm_restore;
+
+ return 0;
+
+rpm_restore:
+ if (adc->was_rpm_active) {
+ pm_runtime_mark_last_busy(dev);
+ pm_runtime_put_autosuspend(dev);
+ }
+resets_restore:
+ reset_control_bulk_assert(ARRAY_SIZE(resets), resets);
+ return ret;
+}
+
static const struct dev_pm_ops rzg2l_adc_pm_ops = {
RUNTIME_PM_OPS(rzg2l_adc_pm_runtime_suspend, rzg2l_adc_pm_runtime_resume, NULL)
+ SYSTEM_SLEEP_PM_OPS(rzg2l_adc_suspend, rzg2l_adc_resume)
};

static struct platform_driver rzg2l_adc_driver = {
--
2.39.2