linux-kernel - [PATCH v7 2/8] iio: adc: ad7606: move 'val' pointer to ad7606_scan

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Message-ID: <20240919130444.2100447-3-aardelean@baylibre.com>
Date: Thu, 19 Sep 2024 16:04:37 +0300
From: Alexandru Ardelean <aardelean@...libre.com>
To: linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org
Cc: jic23@...nel.org,
	krzk+dt@...nel.org,
	robh@...nel.org,
	lars@...afoo.de,
	michael.hennerich@...log.com,
	gstols@...libre.com,
	dlechner@...libre.com,
	Alexandru Ardelean <aardelean@...libre.com>
Subject: [PATCH v7 2/8] iio: adc: ad7606: move 'val' pointer to ad7606_scan_direct()

The ad7606_scan_direct() function returns 'int', which is fine for 16-bit
samples.
But when going to 18-bit samples, these need to be implemented as 32-bit
(or int) type.

In that case when getting samples (which can be negative), we'd get random
error codes.
So, the easiest thing is to just move the 'val' pointer to
'ad7606_scan_direct()'. This doesn't qualify as a fix, it's just a
preparation for 18-bit ADCs (of the AD7606 family).

Reviewed-by: David Lechner <dlechner@...libre.com>
Signed-off-by: Alexandru Ardelean <aardelean@...libre.com>
---
 drivers/iio/adc/ad7606.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/adc/ad7606.c b/drivers/iio/adc/ad7606.c
index 8ebfe8abc3f4..032a8135c912 100644
--- a/drivers/iio/adc/ad7606.c
+++ b/drivers/iio/adc/ad7606.c
@@ -114,7 +114,8 @@ static irqreturn_t ad7606_trigger_handler(int irq, void *p)
 	return IRQ_HANDLED;
 }
 
-static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
+static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch,
+			      int *val)
 {
 	struct ad7606_state *st = iio_priv(indio_dev);
 	int ret;
@@ -128,8 +129,10 @@ static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
 	}
 
 	ret = ad7606_read_samples(st);
-	if (ret == 0)
-		ret = st->data[ch];
+	if (ret)
+		goto error_ret;
+
+	*val = sign_extend32(st->data[ch], 15);
 
 error_ret:
 	gpiod_set_value(st->gpio_convst, 0);
@@ -149,10 +152,9 @@ static int ad7606_read_raw(struct iio_dev *indio_dev,
 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
 		iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
-			ret = ad7606_scan_direct(indio_dev, chan->address);
+			ret = ad7606_scan_direct(indio_dev, chan->address, val);
 			if (ret < 0)
 				return ret;
-			*val = (short) ret;
 			return IIO_VAL_INT;
 		}
 		unreachable();
-- 
2.46.0