The data-sheet of AD7124, from the Sigma-Delta ADC family,
recommends that the falling edge of the DOUT line should be used for
an interrupt.
The ad_sigma_delta implementation hardcodes the irq trigger type
to low, assuming that all Sigma-Delta ADCs have the same interrupt-type.
This causes unwanted behaviour. If DOUT line is already low, the
interrupt will fire once, when enabled and the irq handler will send a
read request to the device. At this time the device has not yet finished
the previous conversion and will give a bad reading.
This patch allows drivers using the ad_sigma_delta layer to set the
irq trigger type to the one specified in the corresponding data-sheet.
Signed-off-by: Alexandru Tachici <alexandru.tachici@xxxxxxxxxx>
---
drivers/iio/adc/ad_sigma_delta.c | 11 ++++++++++-
include/linux/iio/adc/ad_sigma_delta.h | 5 +++++
2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
index 8ba90486c787..ef8c356b11ee 100644
--- a/drivers/iio/adc/ad_sigma_delta.c
+++ b/drivers/iio/adc/ad_sigma_delta.c
@@ -500,7 +500,7 @@ static int ad_sd_probe_trigger(struct iio_dev *indio_dev)
ret = request_irq(sigma_delta->spi->irq,
ad_sd_data_rdy_trig_poll,
- IRQF_TRIGGER_LOW,
+ sigma_delta->irq_flags,
indio_dev->name,
sigma_delta);
if (ret)
@@ -586,8 +586,17 @@ EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger);
int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
struct spi_device *spi, const struct ad_sigma_delta_info *info)
{
+ unsigned long set_trigger_flags;
+
sigma_delta->spi = spi;
sigma_delta->info = info;
+ sigma_delta->num_slots = 1;
+ sigma_delta->active_slots = 1;
+
+ set_trigger_flags = sigma_delta->irq_flags & IRQF_TRIGGER_MASK;
+ if (set_trigger_flags == IRQF_TRIGGER_NONE)
+ sigma_delta->irq_flags |= IRQF_TRIGGER_LOW;
+
iio_device_set_drvdata(indio_dev, sigma_delta);
return 0;
diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h
index 8a4e25a7080c..0d3fa1e16f5e 100644
--- a/include/linux/iio/adc/ad_sigma_delta.h
+++ b/include/linux/iio/adc/ad_sigma_delta.h
@@ -55,6 +55,8 @@ struct ad_sigma_delta_info {
* struct ad_sigma_delta - Sigma Delta device struct
* @spi: The spi device associated with the Sigma Delta device.
* @trig: The IIO trigger associated with the Sigma Delta device.
+ * @num_slots: Number of sequencer slots
+ * @irq_flags: flags for the interrupt used by the triggered buffer
*
* Most of the fields are private to the sigma delta library code and should not
* be accessed by individual drivers.
@@ -63,6 +65,9 @@ struct ad_sigma_delta {
struct spi_device *spi;
struct iio_trigger *trig;
+ unsigned int num_slots;
+ unsigned long irq_flags;
+
/* private: */
struct completion completion;
bool irq_dis;
--
2.20.1
