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[109.252.193.103]) by smtp.gmail.com with ESMTPSA id u6sm94758lfr.164.2021.04.21.16.49.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Apr 2021 16:49:51 -0700 (PDT) From: Dmitry Osipenko To: Linus Walleij , Jonathan Cameron , Lars-Peter Clausen , Andy Shevchenko , Maxim Schwalm , Svyatoslav Ryhel Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v1] iio: gyro: mpu3050: Fix reported temperature value Date: Thu, 22 Apr 2021 02:48:20 +0300 Message-Id: <20210421234820.32211-1-digetx@gmail.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org The raw temperature value is a signed 16bit integer. The sign casting is missed in the code, which results in a wrong temperature reported by userspace tools, fix it. Cc: stable@vger.kernel.org Link: https://www.cdiweb.com/datasheets/invensense/mpu-3000a.pdf Tested-by: Maxim Schwalm # Asus TF700T Tested-by: Svyatoslav Ryhel # Asus TF201 Reported-by: Svyatoslav Ryhel Signed-off-by: Dmitry Osipenko Reviewed-by: Linus Walleij --- drivers/iio/gyro/mpu3050-core.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/iio/gyro/mpu3050-core.c b/drivers/iio/gyro/mpu3050-core.c index ac90be03332a..9885428ca12e 100644 --- a/drivers/iio/gyro/mpu3050-core.c +++ b/drivers/iio/gyro/mpu3050-core.c @@ -272,7 +272,16 @@ static int mpu3050_read_raw(struct iio_dev *indio_dev, 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, + * where 23000 includes room temperature offset of + * +35C, 280 is the precision scale and x is the signed + * 16bit integer which corresponds to the temperature + * range of -40C..85C. + * + * Temperature value itself represents temperature of + * the sensor die. + */ *val = 23000; return IIO_VAL_INT; default: @@ -329,7 +338,7 @@ static int mpu3050_read_raw(struct iio_dev *indio_dev, 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;