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path: root/drivers/iio/adc/palmas_gpadc.c
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Diffstat (limited to 'drivers/iio/adc/palmas_gpadc.c')
-rw-r--r--drivers/iio/adc/palmas_gpadc.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/drivers/iio/adc/palmas_gpadc.c b/drivers/iio/adc/palmas_gpadc.c
index 889b88768b63..6ef09609be9f 100644
--- a/drivers/iio/adc/palmas_gpadc.c
+++ b/drivers/iio/adc/palmas_gpadc.c
@@ -90,6 +90,12 @@ static struct palmas_gpadc_info palmas_gpadc_info[] = {
* 3: 800 uA
* @extended_delay: enable the gpadc extended delay mode
* @auto_conversion_period: define the auto_conversion_period
+ * @lock: Lock to protect the device state during a potential concurrent
+ * read access from userspace. Reading a raw value requires a sequence
+ * of register writes, then a wait for a completion callback,
+ * and finally a register read, during which userspace could issue
+ * another read request. This lock protects a read access from
+ * ocurring before another one has finished.
*
* This is the palmas_gpadc structure to store run-time information
* and pointers for this driver instance.
@@ -110,6 +116,7 @@ struct palmas_gpadc {
bool wakeup1_enable;
bool wakeup2_enable;
int auto_conversion_period;
+ struct mutex lock;
};
/*
@@ -388,7 +395,7 @@ static int palmas_gpadc_read_raw(struct iio_dev *indio_dev,
if (adc_chan > PALMAS_ADC_CH_MAX)
return -EINVAL;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&adc->lock);
switch (mask) {
case IIO_CHAN_INFO_RAW:
@@ -414,12 +421,12 @@ static int palmas_gpadc_read_raw(struct iio_dev *indio_dev,
goto out;
}
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&adc->lock);
return ret;
out:
palmas_gpadc_read_done(adc, adc_chan);
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&adc->lock);
return ret;
}
@@ -516,8 +523,11 @@ static int palmas_gpadc_probe(struct platform_device *pdev)
adc->dev = &pdev->dev;
adc->palmas = dev_get_drvdata(pdev->dev.parent);
adc->adc_info = palmas_gpadc_info;
+
+ mutex_init(&adc->lock);
+
init_completion(&adc->conv_completion);
- dev_set_drvdata(&pdev->dev, indio_dev);
+ platform_set_drvdata(pdev, indio_dev);
adc->auto_conversion_period = gpadc_pdata->auto_conversion_period_ms;
adc->irq = palmas_irq_get_virq(adc->palmas, PALMAS_GPADC_EOC_SW_IRQ);