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Commit afc31875 authored by Jean Delvare's avatar Jean Delvare
Browse files

hwmon: (pcf8591) Documentation clean-ups 



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: default avatarJean Delvare <khali@linux-fr.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
parent 61cba5c2

Documentation/hwmon/pcf8591

+15 −13
Original line number Diff line number Diff line
@@ -2,11 +2,11 @@ Kernel driver pcf8591 
=====================



Supported chips:

  * Philips PCF8591

  * Philips/NXP PCF8591

    Prefix: 'pcf8591'

    Addresses scanned: I2C 0x48 - 0x4f

    Datasheet: Publicly available at the Philips Semiconductor website

               http://www.semiconductors.philips.com/pip/PCF8591P.html

    Datasheet: Publicly available at the NXP website

               http://www.nxp.com/pip/PCF8591_6.html



Authors:

        Aurelien Jarno <aurelien@aurel32.net>
@@ -16,9 +16,10 @@ Authors: 


Description

-----------



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

is designed to provide a byte I2C interface to up to 4 separate devices.

analog output) for the I2C bus produced by Philips Semiconductors (now NXP).

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

differential inputs :
@@ -59,7 +60,7 @@ Accessing PCF8591 via /sys interface 


! Be careful !

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

range, the workaround is to load this module after the one

for your others chips.
@@ -67,19 +68,20 @@ for your others chips. 
On detection (i.e. insmod, modprobe et al.), directories are being

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)

and <1> the chip address ([48..4f])



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.



The in0, in1, in2 and in3 files are RO. Reading gives the value of the

corresponding channel. Depending on the current analog inputs configuration,

files in2 and/or in3 do not exist. Values range are from 0 to 255 for single

ended inputs and -128 to +127 for differential inputs (8-bit ADC).

The in0_input, in1_input, in2_input and in3_input files are RO. Reading gives

the value of the corresponding channel. Depending on the current analog inputs

configuration, files in2_input and in3_input may not exist. Values range

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

"0" for analog output disabled. Writing accepts "0" and "1" accordingly.