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>

diff --git a/drivers/iio/temperature/tsys01.c b/drivers/iio/temperature/tsys01.c
index 334bba6fdae6cb87d81d697f265eb5649cd00bb9..104dd45598b0c51ffda0050d432a0cb66b9230dc 100644 (file)
--- 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);
 }