5.15-stable review patch. If anyone has any objections, please let me know.
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From: Alexander Zangerl az@breathe-safe.com
commit fd39d9668f2ce9f4b05ad55e8c8d80c098073e0b upstream.
The ms5611 driver falsely rejects lots of MS5607-02BA03-50 chips with "PROM integrity check failed" because it doesn't accept a prom crc value of zero as legitimate.
According to the datasheet for this chip (and the manufacturer's application note about the PROM CRC), none of the possible values for the CRC are excluded - but the current code in ms5611_prom_is_valid() ends with
return crc_orig != 0x0000 && crc == crc_orig
Discussed with the driver author (Tomasz Duszynski) and he indicated that at that time (2015) he was dealing with some faulty chip samples which returned blank data under some circumstances and/or followed example code which indicated CRC zero being bad.
As far as I can tell this exception should not be applied anymore; We've got a few hundred custom boards here with this chip where large numbers of the prom have a legitimate CRC value 0, and do work fine, but which the current driver code wrongly rejects.
Signed-off-by: Alexander Zangerl az@breathe-safe.com Fixes: c0644160a8b5 ("iio: pressure: add support for MS5611 pressure and temperature sensor") Link: https://lore.kernel.org/r/2535-1695168070.831792@Ze3y.dhYT.s3fx Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/pressure/ms5611_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/iio/pressure/ms5611_core.c +++ b/drivers/iio/pressure/ms5611_core.c @@ -76,7 +76,7 @@ static bool ms5611_prom_is_valid(u16 *pr
crc = (crc >> 12) & 0x000F;
- return crc_orig != 0x0000 && crc == crc_orig; + return crc == crc_orig; }
static int ms5611_read_prom(struct iio_dev *indio_dev)