linux-kernel - [PATCH v4 16/16] iio: adc: max1027: Don't reject external triggers when there is no IRQ

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Date:   Tue, 21 Sep 2021 13:54:08 +0200
From:   Miquel Raynal <miquel.raynal@...tlin.com>
To:     Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Nuno Sa <Nuno.Sa@...log.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>
Subject: [PATCH v4 16/16] iio: adc: max1027: Don't reject external triggers when there is no IRQ

External triggers do not necessarily need the EOC interrupt to be
populated to work properly. The end of conversion status may either come
from an interrupt or from a sufficient enough extra delay. IRQs are not
mandatory so move the triggered buffer setup out of the IRQ condition
and add the logic to wait enough time for all the requested conversions
to be in the device's FIFO.

Signed-off-by: Miquel Raynal <miquel.raynal@...tlin.com>
---
 drivers/iio/adc/max1027.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
index 02735c604f82..45dc8a625fa3 100644
--- a/drivers/iio/adc/max1027.c
+++ b/drivers/iio/adc/max1027.c
@@ -288,6 +288,9 @@ static int max1027_wait_eoc(struct iio_dev *indio_dev)
 		if (!ret)
 			return ret;
 	} else {
+		if (indio_dev->active_scan_mask)
+			conversion_time *= hweight32(*indio_dev->active_scan_mask);
+
 		usleep_range(conversion_time, conversion_time * 2);
 	}
 
@@ -567,16 +570,18 @@ static int max1027_probe(struct spi_device *spi)
 	if (!st->buffer)
 		return -ENOMEM;
 
+	/* Enable triggered buffers */
+	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
+					      &iio_pollfunc_store_time,
+					      &max1027_trigger_handler,
+					      NULL);
+	if (ret < 0) {
+		dev_err(&indio_dev->dev, "Failed to setup buffer\n");
+		return ret;
+	}
+
+	/* If there is an EOC interrupt, register the cnvst hardware trigger */
 	if (spi->irq) {
-		ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
-						      &iio_pollfunc_store_time,
-						      &max1027_trigger_handler,
-						      NULL);
-		if (ret < 0) {
-			dev_err(&indio_dev->dev, "Failed to setup buffer\n");
-			return ret;
-		}
-
 		st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-trigger",
 						  indio_dev->name);
 		if (!st->trig) {
-- 
2.27.0