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-rw-r--r--Documentation/hwmon/pcf859128
1 files changed, 15 insertions, 13 deletions
diff --git a/Documentation/hwmon/pcf8591 b/Documentation/hwmon/pcf8591
index 5628fcf4207f..e76a7892f68e 100644
--- a/Documentation/hwmon/pcf8591
+++ b/Documentation/hwmon/pcf8591
@@ -2,11 +2,11 @@ Kernel driver pcf8591
2===================== 2=====================
3 3
4Supported chips: 4Supported chips:
5 * Philips PCF8591 5 * Philips/NXP PCF8591
6 Prefix: 'pcf8591' 6 Prefix: 'pcf8591'
7 Addresses scanned: I2C 0x48 - 0x4f 7 Addresses scanned: I2C 0x48 - 0x4f
8 Datasheet: Publicly available at the Philips Semiconductor website 8 Datasheet: Publicly available at the NXP website
9 http://www.semiconductors.philips.com/pip/PCF8591P.html 9 http://www.nxp.com/pip/PCF8591_6.html
10 10
11Authors: 11Authors:
12 Aurelien Jarno <aurelien@aurel32.net> 12 Aurelien Jarno <aurelien@aurel32.net>
@@ -16,9 +16,10 @@ Authors:
16 16
17Description 17Description
18----------- 18-----------
19
19The PCF8591 is an 8-bit A/D and D/A converter (4 analog inputs and one 20The PCF8591 is an 8-bit A/D and D/A converter (4 analog inputs and one
20analog output) for the I2C bus produced by Philips Semiconductors. It 21analog output) for the I2C bus produced by Philips Semiconductors (now NXP).
21is designed to provide a byte I2C interface to up to 4 separate devices. 22It is designed to provide a byte I2C interface to up to 4 separate devices.
22 23
23The PCF8591 has 4 analog inputs programmable as single-ended or 24The PCF8591 has 4 analog inputs programmable as single-ended or
24differential inputs : 25differential inputs :
@@ -58,8 +59,8 @@ Accessing PCF8591 via /sys interface
58------------------------------------- 59-------------------------------------
59 60
60! Be careful ! 61! Be careful !
61The PCF8591 is plainly impossible to detect ! Stupid chip. 62The PCF8591 is plainly impossible to detect! Stupid chip.
62So every chip with address in the interval [48..4f] is 63So every chip with address in the interval [0x48..0x4f] is
63detected as PCF8591. If you have other chips in this address 64detected as PCF8591. If you have other chips in this address
64range, the workaround is to load this module after the one 65range, the workaround is to load this module after the one
65for your others chips. 66for your others chips.
@@ -67,19 +68,20 @@ for your others chips.
67On detection (i.e. insmod, modprobe et al.), directories are being 68On detection (i.e. insmod, modprobe et al.), directories are being
68created for each detected PCF8591: 69created for each detected PCF8591:
69 70
70/sys/bus/devices/<0>-<1>/ 71/sys/bus/i2c/devices/<0>-<1>/
71where <0> is the bus the chip was detected on (e. g. i2c-0) 72where <0> is the bus the chip was detected on (e. g. i2c-0)
72and <1> the chip address ([48..4f]) 73and <1> the chip address ([48..4f])
73 74
74Inside these directories, there are such files: 75Inside these directories, there are such files:
75in0, in1, in2, in3, out0_enable, out0_output, name 76in0_input, in1_input, in2_input, in3_input, out0_enable, out0_output, name
76 77
77Name contains chip name. 78Name contains chip name.
78 79
79The in0, in1, in2 and in3 files are RO. Reading gives the value of the 80The in0_input, in1_input, in2_input and in3_input files are RO. Reading gives
80corresponding channel. Depending on the current analog inputs configuration, 81the value of the corresponding channel. Depending on the current analog inputs
81files in2 and/or in3 do not exist. Values range are from 0 to 255 for single 82configuration, files in2_input and in3_input may not exist. Values range
82ended inputs and -128 to +127 for differential inputs (8-bit ADC). 83from 0 to 255 for single ended inputs and -128 to +127 for differential inputs
84(8-bit ADC).
83 85
84The out0_enable file is RW. Reading gives "1" for analog output enabled and 86The out0_enable file is RW. Reading gives "1" for analog output enabled and
85"0" for analog output disabled. Writing accepts "0" and "1" accordingly. 87"0" for analog output disabled. Writing accepts "0" and "1" accordingly.