• Linus Walleij's avatar
    iio: accel: st_accel: fix LIS3LV02 reading and scaling · 65e4345c
    Linus Walleij authored
    The LIS3LV02 has a special bit that need to be set to get the
    read values left aligned. Before this patch we get gibberish
    like this:
    
    iio_generic_buffer -a -c10 -n lis3lv02dl_accel
    (...)
    0.000000 -0.010042 -0.642688 19155832931907
    0.000000 -0.010042 -0.642688 19155858751073
    
    Which is because we read a raw value for 1g as 64 which is
    the nominal 1024 for 1g shifted 4 bits to the left by being
    right-aligned rather than left aligned.
    
    Since all other sensors are left aligned, add some code to
    set the special DAS (data alignment setting) bit to 1 so that
    the right value is now read like this:
    
    iio_generic_buffer -a -c10 -n lis3lv02dl_accel
    (...)
    0.000000 -0.147095 -10.120135 24761614364956
    -0.029419 -0.176514 -10.120135 24761631624540
    
    The scaling was weird as well: we have a gain of 1000 for 1g
    and 3000 for 6g. I don't even remember how I came up with the
    old values but they are wrong.
    
    Fixes: 3acddf74 ("iio: st-sensors: add support for lis3lv02d accelerometer")
    Cc: Lorenzo Bianconi <lorenzo.bianconi@st.com>
    Cc: Giuseppe Barba <giuseppe.barba@st.com>
    Cc: Denis Ciocca <denis.ciocca@st.com>
    Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
    Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
    65e4345c
st_sensors.h 9.53 KB