From 652e7df485c6884d552085ae2c73efa6cfea3547 Mon Sep 17 00:00:00 2001
From: Gwendal Grignou <gwendal@chromium.org>
Date: Thu, 4 Nov 2021 01:24:08 -0700
Subject: [PATCH] iio: at91-sama5d2: Fix incorrect sign extension
Git-commit: 652e7df485c6884d552085ae2c73efa6cfea3547
Patch-mainline: v5.16-rc5
References: git-fixes

Use scan_type when processing raw data which also fixes that the sign
extension was from the wrong bit.

Use channel definition as root of trust and replace constant
when reading elements directly using the raw sysfs attributes.

Fixes: 6794e23fa3fe ("iio: adc: at91-sama5d2_adc: add support for oversampling resolution")
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Eugen Hristev <eugen.hristev@microchip.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20211104082413.3681212-9-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/iio/adc/at91-sama5d2_adc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index 4c922ef634f8..92a57cf10fba 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -1586,7 +1586,8 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev,
 		*val = st->conversion_value;
 		ret = at91_adc_adjust_val_osr(st, val);
 		if (chan->scan_type.sign == 's')
-			*val = sign_extend32(*val, 11);
+			*val = sign_extend32(*val,
+					     chan->scan_type.realbits - 1);
 		st->conversion_done = false;
 	}
 
-- 
2.31.1