patch "iio: temperature: tsys01: fix broken PROM checksum validation" added to char-misc-linus

patch "iio: temperature: tsys01: fix broken PROM checksum validation" added to char-misc-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    iio: temperature: tsys01: fix broken PROM checksum validation

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From 4701e471c16866e7aa8f5e6a3a6b0d31e097e2c9 Mon Sep 17 00:00:00 2001
From: Salah Triki <salah.triki@gmail.com>
Date: Tue, 5 May 2026 08:10:24 +0100
Subject: iio: temperature: tsys01: fix broken PROM checksum validation

The current implementation of tsys01_crc_valid() incorrectly sums the
first word (n_prom[0]) repeatedly instead of iterating over the 8 words
retrieved from the PROM. This leads to a checksum mismatch and probe
failure on hardware.

According to the TSYS01 datasheet, the PROM consists of 8 words. A valid
check must iterate through all 8 words to verify the integrity of the
calibration data. The current driver only checks the first word 8 times.

Note: This fix was identified during a code audit and is based on
datasheet specifications. It has not been tested on real hardware.

Fixes: 43e53407f680 ("Add tsys01 meas-spec driver support")
Signed-off-by: Salah Triki <salah.triki@gmail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/iio/temperature/tsys01.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/temperature/tsys01.c b/drivers/iio/temperature/tsys01.c
index 334bba6fdae6..104dd45598b0 100644
--- a/drivers/iio/temperature/tsys01.c
+++ b/drivers/iio/temperature/tsys01.c
@@ -119,7 +119,7 @@ static bool tsys01_crc_valid(u16 *n_prom)
 	u8 sum = 0;
 
 	for (cnt = 0; cnt < TSYS01_PROM_WORDS_NB; cnt++)
-		sum += ((n_prom[0] >> 8) + (n_prom[0] & 0xFF));
+		sum += ((n_prom[cnt] >> 8) + (n_prom[cnt] & 0xFF));
 
 	return (sum == 0);
 }
-- 
2.54.0