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From: <marius.cristea@microchip.com>
To: <jic23@kernel.org>, <lars@metafoo.de>, <lgirdwood@gmail.com>,
	<broonie@kernel.org>
CC: <linux-iio@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<conor+dt@kernel.org>, <marius.cristea@microchip.com>
Subject: [PATCH v1] iio: adc: PAC1934: fix accessing out of bounds array index
Date: Thu, 25 Apr 2024 14:42:32 +0300
Message-ID: <20240425114232.81390-1-marius.cristea@microchip.com>
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From: Marius Cristea <marius.cristea@microchip.com>

Fix accessing out of bounds array index for average
current and voltage measurements. The device itself has
only 4 channels, but in sysfs there are "fake"
channels for the average voltages and currents too.

Fixes: 0fb528c8255b: "iio: adc: adding support for PAC193x"
Reported-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
---
 drivers/iio/adc/pac1934.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/iio/adc/pac1934.c b/drivers/iio/adc/pac1934.c
index f751260605e4..456f12faa348 100644
--- a/drivers/iio/adc/pac1934.c
+++ b/drivers/iio/adc/pac1934.c
@@ -787,6 +787,15 @@ static int pac1934_read_raw(struct iio_dev *indio_dev,
 	s64 curr_energy;
 	int ret, channel = chan->channel - 1;
 
+	/*
+	 * For AVG the index should be between 5 to 8.
+	 * To calculate PAC1934_CH_VOLTAGE_AVERAGE,
+	 * respectively PAC1934_CH_CURRENT real index, we need
+	 * to remove the added offset (PAC1934_MAX_NUM_CHANNELS).
+	 */
+	if (channel >= PAC1934_MAX_NUM_CHANNELS)
+		channel = channel - PAC1934_MAX_NUM_CHANNELS;
+
 	ret = pac1934_retrieve_data(info, PAC1934_MIN_UPDATE_WAIT_TIME_US);
 	if (ret < 0)
 		return ret;

base-commit: b80ad8e3cd2712b78b98804d1f59199680d8ed91
-- 
2.34.1