linux-kernel - [PATCH v2 06/19] staging: iio: resolver: ad2s1210: always use 16-bit value for raw read

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Message-Id: <20230921144400.62380-7-dlechner@baylibre.com>
Date:   Thu, 21 Sep 2023 09:43:47 -0500
From:   David Lechner <dlechner@...libre.com>
To:     linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-staging@...ts.linux.dev
Cc:     linux-kernel@...r.kernel.org, Jonathan Cameron <jic23@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Michael Hennerich <Michael.Hennerich@...log.com>,
        Nuno Sá <nuno.sa@...log.com>,
        Axel Haslam <ahaslam@...libre.com>,
        Philip Molloy <pmolloy@...libre.com>,
        David Lechner <dlechner@...libre.com>
Subject: [PATCH v2 06/19] staging: iio: resolver: ad2s1210: always use 16-bit value for raw read

This removes the special handling for resolutions lower than 16 bits.
This will allow us to use a fixed scale independent of the resolution.

Also, for the record, according to the datasheet, the logic for the
special handling based on hysteresis that was removed was incorrect.

Signed-off-by: David Lechner <dlechner@...libre.com>
---
 drivers/staging/iio/resolver/ad2s1210.c | 16 ++--------------
 1 file changed, 2 insertions(+), 14 deletions(-)

diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
index 9c7f76114360..985b8fecd65a 100644
--- a/drivers/staging/iio/resolver/ad2s1210.c
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -465,10 +465,7 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,
 			     long m)
 {
 	struct ad2s1210_state *st = iio_priv(indio_dev);
-	u16 negative;
 	int ret = 0;
-	u16 pos;
-	s16 vel;
 
 	mutex_lock(&st->lock);
 	gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 0);
@@ -494,20 +491,11 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,
 
 	switch (chan->type) {
 	case IIO_ANGL:
-		pos = be16_to_cpup((__be16 *)st->rx);
-		if (st->hysteresis)
-			pos >>= 16 - st->resolution;
-		*val = pos;
+		*val = be16_to_cpup((__be16 *)st->rx);
 		ret = IIO_VAL_INT;
 		break;
 	case IIO_ANGL_VEL:
-		vel = be16_to_cpup((__be16 *)st->rx);
-		vel >>= 16 - st->resolution;
-		if (vel & 0x8000) {
-			negative = (0xffff >> st->resolution) << st->resolution;
-			vel |= negative;
-		}
-		*val = vel;
+		*val = (s16)be16_to_cpup((__be16 *)st->rx);
 		ret = IIO_VAL_INT;
 		break;
 	default:
-- 
2.34.1