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iio:pressure:bmp280: fix pressure calculation 

According to the datasheet and as defined in struct bmp280_comp_press, dig_p1 is
of type u16, while dig_p2 to dig_p9 are of type s16. In
bmp280_read_compensation_press(), values read from the device were treated as
the wrong type.
In bmp280_read_press() the fractional part of the measured pressure is
calculated wrong. A better way is to use *val for the raw pressure and *val2 for
the quotient and let the core do the proper conversion using IIO_VAL_FRACTIONAL.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Acked-by: Vlad Dogaru <vlad.dogaru@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Hartmut Knaack 2014-10-31 01:22:00 +00:00 committed by Jonathan Cameron
parent c1b501564c
commit 81ebe850a0
1 changed files with 12 additions and 12 deletions
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24
drivers/iio/pressure/bmp280.c
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@ -176,15 +176,15 @@ static int bmp280_read_compensation_press(struct bmp280_data *data,
return ret;
}
comp->dig_p1 = (s16) le16_to_cpu(buf[0]);
comp->dig_p2 = (u16) le16_to_cpu(buf[1]);
comp->dig_p3 = (u16) le16_to_cpu(buf[2]);
comp->dig_p4 = (u16) le16_to_cpu(buf[3]);
comp->dig_p5 = (u16) le16_to_cpu(buf[4]);
comp->dig_p6 = (u16) le16_to_cpu(buf[5]);
comp->dig_p7 = (u16) le16_to_cpu(buf[6]);
comp->dig_p8 = (u16) le16_to_cpu(buf[7]);
comp->dig_p9 = (u16) le16_to_cpu(buf[8]);
comp->dig_p1 = (u16) le16_to_cpu(buf[0]);
comp->dig_p2 = (s16) le16_to_cpu(buf[1]);
comp->dig_p3 = (s16) le16_to_cpu(buf[2]);
comp->dig_p4 = (s16) le16_to_cpu(buf[3]);
comp->dig_p5 = (s16) le16_to_cpu(buf[4]);
comp->dig_p6 = (s16) le16_to_cpu(buf[5]);
comp->dig_p7 = (s16) le16_to_cpu(buf[6]);
comp->dig_p8 = (s16) le16_to_cpu(buf[7]);
comp->dig_p9 = (s16) le16_to_cpu(buf[8]);
return 0;
}
@ -309,10 +309,10 @@ static int bmp280_read_press(struct bmp280_data *data,
adc_press = be32_to_cpu(tmp) >> 12;
comp_press = bmp280_compensate_press(data, &comp, adc_press);
*val = comp_press / 256000;
*val2 = comp_press * 1000000 / 256000;
*val = comp_press;
*val2 = 256000;
return IIO_VAL_INT_PLUS_MICRO;
return IIO_VAL_FRACTIONAL;
}
static int bmp280_read_raw(struct iio_dev *indio_dev,