1. 05 3月, 2011 1 次提交
  2. 10 8月, 2010 1 次提交
    • C
      drivers/misc: support for the pressure sensor BMP085 from Bosch Sensortec · 5bf1d290
      Christoph Mair 提交于
      This driver adds support for the BMP085 digital pressure sensor from Bosch
      Sensortec.  It exposes a sysfs api to userspace where pressure and
      temperature measurement results can be read from the pressure0_input and
      temp0_input file.  The chip is able to calculate the average of up to
      eight samples to increase the accuracy.  This feature can be controlled by
      writing to the oversampling file.
      
      The BMP085 digital pressure sensor can measure ambient air pressure and
      temperature.  Both values can be obtained from sysfs files.  The pressure
      is measured by reading from pressure0_input.  Valid values range from
      30000 to 110000 pascal with a resolution of 1 pascal (=0.01 millibar).
      
      temp0_input holds the current temperature in degree celsius, multiplied by
      10.  This results in a resolution of a tenth degree celsius.  Values range
      from -400 to 850.
      
      To increase the accuracy, this chip can calculate the average of 1, 2, 4
      or 8 samples.  This behavior is controlled through the oversampling sysfs
      file.  Two to the power of the value written to that file specifies how
      many samples will be used.  Valid values: 0..3.
      
      [akpm@linux-foundation.org: fix typo]
      [shubhrajyoti@ti.com: optimize the wait time for the pressure sensor, definition of long is arch dependent so make it u32]
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: NChristoph Mair <christoph.mair@gmail.com>
      Signed-off-by: NShubhrajyoti D <shubhrajyoti@ti.com>
      Acked-by: NJonathan Cameron <jic23@cam.ac.uk>
      Cc: Stefan Schmidt <stefan@datenfreihafen.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5bf1d290