iio: adc: stm32-adc: switch off running adc when going to low power

Switch off ADC when going to low power mode, in case it has been left
running in buffer mode. Then re-enable it when resuming.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 1ba800b91273b5aea3bdfaa7a31a898c542ee2d6..205e1699f954fced46bea0e886003a23a0cd0bca 100644 (file)
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -1518,7 +1518,7 @@ static int stm32_adc_dma_start(struct iio_dev *indio_dev)
        return 0;
 }
 
-static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
+static int __stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
 {
        struct stm32_adc *adc = iio_priv(indio_dev);
        struct device *dev = indio_dev->dev.parent;
@@ -1542,10 +1542,6 @@ static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
                goto err_clr_trig;
        }
 
-       ret = iio_triggered_buffer_postenable(indio_dev);
-       if (ret < 0)
-               goto err_stop_dma;
-
        /* Reset adc buffer index */
        adc->bufi = 0;
 
@@ -1556,9 +1552,6 @@ static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
 
        return 0;
 
-err_stop_dma:
-       if (adc->dma_chan)
-               dmaengine_terminate_all(adc->dma_chan);
 err_clr_trig:
        stm32_adc_set_trig(indio_dev, NULL);
 err_pm_put:
@@ -1568,20 +1561,30 @@ err_pm_put:
        return ret;
 }
 
-static int stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
+static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
+{
+       int ret;
+
+       ret = iio_triggered_buffer_postenable(indio_dev);
+       if (ret < 0)
+               return ret;
+
+       ret = __stm32_adc_buffer_postenable(indio_dev);
+       if (ret < 0)
+               iio_triggered_buffer_predisable(indio_dev);
+
+       return ret;
+}
+
+static void __stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
 {
        struct stm32_adc *adc = iio_priv(indio_dev);
        struct device *dev = indio_dev->dev.parent;
-       int ret;
 
        adc->cfg->stop_conv(adc);
        if (!adc->dma_chan)
                stm32_adc_conv_irq_disable(adc);
 
-       ret = iio_triggered_buffer_predisable(indio_dev);
-       if (ret < 0)
-               dev_err(&indio_dev->dev, "predisable failed\n");
-
        if (adc->dma_chan)
                dmaengine_terminate_all(adc->dma_chan);
 
@@ -1590,6 +1593,17 @@ static int stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
 
        pm_runtime_mark_last_busy(dev);
        pm_runtime_put_autosuspend(dev);
+}
+
+static int stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
+{
+       int ret;
+
+       __stm32_adc_buffer_predisable(indio_dev);
+
+       ret = iio_triggered_buffer_predisable(indio_dev);
+       if (ret < 0)
+               dev_err(&indio_dev->dev, "predisable failed\n");
 
        return ret;
 }
@@ -2013,6 +2027,40 @@ static int stm32_adc_remove(struct platform_device *pdev)
        return 0;
 }
 
+#if defined(CONFIG_PM_SLEEP)
+static int stm32_adc_suspend(struct device *dev)
+{
+       struct stm32_adc *adc = dev_get_drvdata(dev);
+       struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+
+       if (iio_buffer_enabled(indio_dev))
+               __stm32_adc_buffer_predisable(indio_dev);
+
+       return pm_runtime_force_suspend(dev);
+}
+
+static int stm32_adc_resume(struct device *dev)
+{
+       struct stm32_adc *adc = dev_get_drvdata(dev);
+       struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+       int ret;
+
+       ret = pm_runtime_force_resume(dev);
+       if (ret < 0)
+               return ret;
+
+       if (!iio_buffer_enabled(indio_dev))
+               return 0;
+
+       ret = stm32_adc_update_scan_mode(indio_dev,
+                                        indio_dev->active_scan_mask);
+       if (ret < 0)
+               return ret;
+
+       return __stm32_adc_buffer_postenable(indio_dev);
+}
+#endif
+
 #if defined(CONFIG_PM)
 static int stm32_adc_runtime_suspend(struct device *dev)
 {
@@ -2026,8 +2074,7 @@ static int stm32_adc_runtime_resume(struct device *dev)
 #endif
 
 static const struct dev_pm_ops stm32_adc_pm_ops = {
-       SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
-                               pm_runtime_force_resume)
+       SET_SYSTEM_SLEEP_PM_OPS(stm32_adc_suspend, stm32_adc_resume)
        SET_RUNTIME_PM_OPS(stm32_adc_runtime_suspend, stm32_adc_runtime_resume,
                           NULL)
 };