This is a note to let you know that I've just added the patch titled iio: gyro: mpu3050: Fix reported temperature value to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: iio-gyro-mpu3050-fix-reported-temperature-value.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From f73c730774d88a14d7b60feee6d0e13570f99499 Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko <digetx@xxxxxxxxx> Date: Fri, 23 Apr 2021 05:09:59 +0300 Subject: iio: gyro: mpu3050: Fix reported temperature value From: Dmitry Osipenko <digetx@xxxxxxxxx> commit f73c730774d88a14d7b60feee6d0e13570f99499 upstream. The raw temperature value is a 16-bit signed integer. The sign casting is missing in the code, which results in a wrong temperature reported by userspace tools, fix it. Cc: stable@xxxxxxxxxxxxxxx Fixes: 3904b28efb2c ("iio: gyro: Add driver for the MPU-3050 gyroscope") Datasheet: https://www.cdiweb.com/datasheets/invensense/mpu-3000a.pdf Tested-by: Maxim Schwalm <maxim.schwalm@xxxxxxxxx> # Asus TF700T Tested-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx> # Asus TF201 Reported-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx> Reviewed-by: Andy Shevchenko <Andy.Shevchenko@xxxxxxxxx> Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx> Acked-by: Jean-Baptiste Maneyrol <jmaneyrol@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210423020959.5023-1-digetx@xxxxxxxxx Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/iio/gyro/mpu3050-core.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) --- a/drivers/iio/gyro/mpu3050-core.c +++ b/drivers/iio/gyro/mpu3050-core.c @@ -270,7 +270,16 @@ static int mpu3050_read_raw(struct iio_d case IIO_CHAN_INFO_OFFSET: switch (chan->type) { case IIO_TEMP: - /* The temperature scaling is (x+23000)/280 Celsius */ + /* + * The temperature scaling is (x+23000)/280 Celsius + * for the "best fit straight line" temperature range + * of -30C..85C. The 23000 includes room temperature + * offset of +35C, 280 is the precision scale and x is + * the 16-bit signed integer reported by hardware. + * + * Temperature value itself represents temperature of + * the sensor die. + */ *val = 23000; return IIO_VAL_INT; default: @@ -327,7 +336,7 @@ static int mpu3050_read_raw(struct iio_d goto out_read_raw_unlock; } - *val = be16_to_cpu(raw_val); + *val = (s16)be16_to_cpu(raw_val); ret = IIO_VAL_INT; goto out_read_raw_unlock; Patches currently in stable-queue which might be from digetx@xxxxxxxxx are queue-4.19/iio-gyro-mpu3050-fix-reported-temperature-value.patch