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hwmon: (pcf8591) Documentation clean-ups

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Clean up the pcf8591 driver documentation:
* The PCF8591 chip is now an NXP product.
* Fix a sysfs path.
* Fix the name of sysfs attributes.
* And a few other random fixes.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Jean Delvare 2009-09-15 17:18:14 +02:00
parent 61cba5c244
commit afc31875fa
1 changed files with 15 additions and 13 deletions
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28
Documentation/hwmon/pcf8591
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@ -2,11 +2,11 @@ Kernel driver pcf8591
===================== =====================
Supported chips: Supported chips:
* Philips PCF8591 * Philips/NXP PCF8591
Prefix: 'pcf8591' Prefix: 'pcf8591'
Addresses scanned: I2C 0x48 - 0x4f Addresses scanned: I2C 0x48 - 0x4f
Datasheet: Publicly available at the Philips Semiconductor website Datasheet: Publicly available at the NXP website
http://www.semiconductors.philips.com/pip/PCF8591P.html http://www.nxp.com/pip/PCF8591_6.html
Authors: Authors:
Aurelien Jarno <aurelien@aurel32.net> Aurelien Jarno <aurelien@aurel32.net>
@ -16,9 +16,10 @@ Authors:
Description Description
----------- -----------
The PCF8591 is an 8-bit A/D and D/A converter (4 analog inputs and one The PCF8591 is an 8-bit A/D and D/A converter (4 analog inputs and one
analog output) for the I2C bus produced by Philips Semiconductors. It analog output) for the I2C bus produced by Philips Semiconductors (now NXP).
is designed to provide a byte I2C interface to up to 4 separate devices. It is designed to provide a byte I2C interface to up to 4 separate devices.
The PCF8591 has 4 analog inputs programmable as single-ended or The PCF8591 has 4 analog inputs programmable as single-ended or
differential inputs : differential inputs :
@ -58,8 +59,8 @@ Accessing PCF8591 via /sys interface
------------------------------------- -------------------------------------
! Be careful ! ! Be careful !
The PCF8591 is plainly impossible to detect ! Stupid chip. The PCF8591 is plainly impossible to detect! Stupid chip.
So every chip with address in the interval [48..4f] is So every chip with address in the interval [0x48..0x4f] is
detected as PCF8591. If you have other chips in this address detected as PCF8591. If you have other chips in this address
range, the workaround is to load this module after the one range, the workaround is to load this module after the one
for your others chips. for your others chips.
@ -67,19 +68,20 @@ for your others chips.
On detection (i.e. insmod, modprobe et al.), directories are being On detection (i.e. insmod, modprobe et al.), directories are being
created for each detected PCF8591: created for each detected PCF8591:
/sys/bus/devices/<0>-<1>/ /sys/bus/i2c/devices/<0>-<1>/
where <0> is the bus the chip was detected on (e. g. i2c-0) where <0> is the bus the chip was detected on (e. g. i2c-0)
and <1> the chip address ([48..4f]) and <1> the chip address ([48..4f])
Inside these directories, there are such files: Inside these directories, there are such files:
in0, in1, in2, in3, out0_enable, out0_output, name in0_input, in1_input, in2_input, in3_input, out0_enable, out0_output, name
Name contains chip name. Name contains chip name.
The in0, in1, in2 and in3 files are RO. Reading gives the value of the The in0_input, in1_input, in2_input and in3_input files are RO. Reading gives
corresponding channel. Depending on the current analog inputs configuration, the value of the corresponding channel. Depending on the current analog inputs
files in2 and/or in3 do not exist. Values range are from 0 to 255 for single configuration, files in2_input and in3_input may not exist. Values range
ended inputs and -128 to +127 for differential inputs (8-bit ADC). from 0 to 255 for single ended inputs and -128 to +127 for differential inputs
(8-bit ADC).
The out0_enable file is RW. Reading gives "1" for analog output enabled and The out0_enable file is RW. Reading gives "1" for analog output enabled and
"0" for analog output disabled. Writing accepts "0" and "1" accordingly. "0" for analog output disabled. Writing accepts "0" and "1" accordingly.