[PATCH v5 2/6] iio: imu: adis: Add irq flag variable

["Nuno Sá" <nuno.sa@analog.com>]

There are some ADIS devices that can configure the data ready pin
polarity. Hence, we cannot hardcode our IRQ mask as IRQF_TRIGGER_RISING
since we might want to have it as IRQF_TRIGGER_FALLING.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
Changes in v2:
 * Add kernel doc-string for `irq-mask`.

Changes in v3:
 * Removed unnecessary inline;
 * Renamed `__adis_validate_irq_mask` to `adis_validate_irq_mask` to keep lib consistency;
 * Cosmetics in logs.

Changes in v4:
 * Use flag suffix instead of mask;
 * Add comments to `adis_validate_irq_flag`.

Changes in v5:
 * Change commit subject to irq flag instead of mask.

 drivers/iio/imu/adis_trigger.c | 33 +++++++++++++++++++++++++++++++--
 include/linux/iio/imu/adis.h   |  2 ++
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/imu/adis_trigger.c b/drivers/iio/imu/adis_trigger.c
index a36810e0b1ab..8afe71947c00 100644
--- a/drivers/iio/imu/adis_trigger.c
+++ b/drivers/iio/imu/adis_trigger.c
@@ -34,6 +34,27 @@ static void adis_trigger_setup(struct adis *adis)
 	iio_trigger_set_drvdata(adis->trig, adis);
 }
 
+static int adis_validate_irq_flag(struct adis *adis)
+{
+	/*
+	 * Typically this devices have data ready either on the rising edge or
+	 * on the falling edge of the data ready pin. This checks enforces that
+	 * one of those is set in the drivers... It defaults to
+	 * IRQF_TRIGGER_RISING for backward compatibility wiht devices that
+	 * don't support changing the pin polarity.
+	 */
+	if (!adis->irq_flag) {
+		adis->irq_flag = IRQF_TRIGGER_RISING;
+		return 0;
+	} else if (adis->irq_flag != IRQF_TRIGGER_RISING &&
+		   adis->irq_flag != IRQF_TRIGGER_FALLING) {
+		dev_err(&adis->spi->dev, "Invalid IRQ mask: %08lx\n",
+			adis->irq_flag);
+		return -EINVAL;
+	}
+
+	return 0;
+}
 /**
  * adis_probe_trigger() - Sets up trigger for a adis device
  * @adis: The adis device
@@ -54,9 +75,13 @@ int adis_probe_trigger(struct adis *adis, struct iio_dev *indio_dev)
 
 	adis_trigger_setup(adis);
 
+	ret = adis_validate_irq_flag(adis);
+	if (ret)
+		return ret;
+
 	ret = request_irq(adis->spi->irq,
 			  &iio_trigger_generic_data_rdy_poll,
-			  IRQF_TRIGGER_RISING,
+			  adis->irq_flag,
 			  indio_dev->name,
 			  adis->trig);
 	if (ret)
@@ -96,9 +121,13 @@ int devm_adis_probe_trigger(struct adis *adis, struct iio_dev *indio_dev)
 
 	adis_trigger_setup(adis);
 
+	ret = adis_validate_irq_flag(adis);
+	if (ret)
+		return ret;
+
 	ret = devm_request_irq(&adis->spi->dev, adis->spi->irq,
 			       &iio_trigger_generic_data_rdy_poll,
-			       IRQF_TRIGGER_RISING,
+			       adis->irq_flag,
 			       indio_dev->name,
 			       adis->trig);
 	if (ret)
diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
index e70814d96e1c..70e4d1d262f5 100644
--- a/include/linux/iio/imu/adis.h
+++ b/include/linux/iio/imu/adis.h
@@ -87,6 +87,7 @@ struct adis_data {
  * @msg: SPI message object
  * @xfer: SPI transfer objects to be used for a @msg
  * @current_page: Some ADIS devices have registers, this selects current page
+ * @irq_flag: IRQ handling flags as passed to request_irq()
  * @buffer: Data buffer for information read from the device
  * @tx: DMA safe TX buffer for SPI transfers
  * @rx: DMA safe RX buffer for SPI transfers
@@ -113,6 +114,7 @@ struct adis {
 	struct spi_message	msg;
 	struct spi_transfer	*xfer;
 	unsigned int		current_page;
+	unsigned long		irq_flag;
 	void			*buffer;
 
 	uint8_t			tx[10] ____cacheline_aligned;
-- 
2.17.1