1 files changed, 33 insertions, 5 deletions

diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
index 3fd200b34161..8fe2ed8b30f9 100644
--- a/drivers/iio/adc/ad_sigma_delta.c
+++ b/drivers/iio/adc/ad_sigma_delta.c
@@ -539,12 +539,29 @@ static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
 {
 	struct ad_sigma_delta *sigma_delta = private;
 
-	complete(&sigma_delta->completion);
-	disable_irq_nosync(irq);
-	sigma_delta->irq_dis = true;
-	iio_trigger_poll(sigma_delta->trig);
+	/*
+	 * AD7124 and a few others use the same physical line for interrupt
+	 * reporting (R̅D̅Y̅) and MISO.
+	 * As MISO toggles when reading a register, this likely results in a
+	 * pending interrupt. This has two consequences: a) The irq might
+	 * trigger immediately after it's enabled even though the conversion
+	 * isn't done yet; and b) checking the STATUS register's R̅D̅Y̅ flag is
+	 * off-limits as reading that would trigger another irq event.
+	 *
+	 * So read the MOSI line as GPIO (if available) and only trigger the irq
+	 * if the line is active. Without such a GPIO assume this is a valid
+	 * interrupt.
+	 */
+	if (!sigma_delta->rdy_gpiod || gpiod_get_value(sigma_delta->rdy_gpiod)) {
+		complete(&sigma_delta->completion);
+		disable_irq_nosync(irq);
+		sigma_delta->irq_dis = true;
+		iio_trigger_poll(sigma_delta->trig);
 
-	return IRQ_HANDLED;
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
 }
 
 /**
@@ -679,6 +696,17 @@ int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
 	else
 		sigma_delta->irq_line = spi->irq;
 
+	sigma_delta->rdy_gpiod = devm_gpiod_get_optional(&spi->dev, "rdy", GPIOD_IN);
+	if (IS_ERR(sigma_delta->rdy_gpiod))
+		return dev_err_probe(&spi->dev, PTR_ERR(sigma_delta->rdy_gpiod),
+				     "Failed to find rdy gpio\n");
+
+	if (sigma_delta->rdy_gpiod && !sigma_delta->irq_line) {
+		sigma_delta->irq_line = gpiod_to_irq(sigma_delta->rdy_gpiod);
+		if (sigma_delta->irq_line < 0)
+			return sigma_delta->irq_line;
+	}
+
 	iio_device_set_drvdata(indio_dev, sigma_delta);
 
 	return 0;