[PATCH 2/2] bmp085: Add interface documentation and link to datasheet.
From: Christoph Mair
Date: Sat Jun 26 2010 - 08:12:27 EST
Signed-off-by: Christoph Mair <christoph.mair@xxxxxxxxx>
drivers/misc/bmp085.c | 27 +++++++++++++++++++++++++++
1 files changed, 27 insertions(+), 0 deletions(-)
diff --git a/drivers/misc/bmp085.c b/drivers/misc/bmp085.c
index 16a2b2c..67ed8b2 100644
@@ -1,5 +1,32 @@
/* Copyright (c) 2010 Christoph Mair <christoph.mair@xxxxxxxxx>
+ This driver supports the bmp085 digital barometric pressure
+ and temperature sensor from Bosch Sensortec. The datasheet
+ is avaliable from their website:
+ A pressure measurement is issued by reading from pressure0_input.
+ The return value ranges from 30000 to 110000 pascal with a resulution
+ of 1 pascal (0.01 millibar) which enables measurements from 9000m above
+ to 500m below sea level.
+ The temperature can be read from temp0_input. Values range from
+ -400 to 850 representing the ambient temperature in degree celsius
+ multiplied by 10.The resolution is 0.1 celsius.
+ Because ambient pressure is temperature dependent, a temperature
+ measurement will be executed automatically even if the user is reading
+ from pressure0_input. This happens if the last temperature measurement
+ has been executed more then one second ago.
+ To decrease RMS noise from pressure measurements, the bmp085 can
+ autonomously calculate the average of up to eight samples. This is
+ set up by writing to the oversampling sysfs file. Accepted values
+ are 0, 1, 2 and 3. 2^x when x is the value written to this file
+ specifies the number of samples used to calculate the ambient pressure.
+ RMS noise is specified with six pascal (without averaging) and decreases
+ down to 3 pascal when using an oversampling setting of 3.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
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