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Subject[PATCH 3/3] iio: adc: stm32-adc: switch off running adc when going to low power
Date
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>
---
drivers/iio/adc/stm32-adc.c | 79 ++++++++++++++++++++++++++++++++++++---------
1 file changed, 63 insertions(+), 16 deletions(-)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 32c9c61..2a9891c 100644
--- 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 @@ static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
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)
};
--
1.9.1
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