diff options
| -rw-r--r-- | Documentation/hwmon/pcf8591 | 28 |
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 | ||
| 4 | Supported chips: | 4 | Supported 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 | ||
| 11 | Authors: | 11 | Authors: |
| 12 | Aurelien Jarno <aurelien@aurel32.net> | 12 | Aurelien Jarno <aurelien@aurel32.net> |
| @@ -16,9 +16,10 @@ Authors: | |||
| 16 | 16 | ||
| 17 | Description | 17 | Description |
| 18 | ----------- | 18 | ----------- |
| 19 | |||
| 19 | The PCF8591 is an 8-bit A/D and D/A converter (4 analog inputs and one | 20 | The PCF8591 is an 8-bit A/D and D/A converter (4 analog inputs and one |
| 20 | analog output) for the I2C bus produced by Philips Semiconductors. It | 21 | analog output) for the I2C bus produced by Philips Semiconductors (now NXP). |
| 21 | is designed to provide a byte I2C interface to up to 4 separate devices. | 22 | It is designed to provide a byte I2C interface to up to 4 separate devices. |
| 22 | 23 | ||
| 23 | The PCF8591 has 4 analog inputs programmable as single-ended or | 24 | The PCF8591 has 4 analog inputs programmable as single-ended or |
| 24 | differential inputs : | 25 | differential inputs : |
| @@ -58,8 +59,8 @@ Accessing PCF8591 via /sys interface | |||
| 58 | ------------------------------------- | 59 | ------------------------------------- |
| 59 | 60 | ||
| 60 | ! Be careful ! | 61 | ! Be careful ! |
| 61 | The PCF8591 is plainly impossible to detect ! Stupid chip. | 62 | The PCF8591 is plainly impossible to detect! Stupid chip. |
| 62 | So every chip with address in the interval [48..4f] is | 63 | So every chip with address in the interval [0x48..0x4f] is |
| 63 | detected as PCF8591. If you have other chips in this address | 64 | detected as PCF8591. If you have other chips in this address |
| 64 | range, the workaround is to load this module after the one | 65 | range, the workaround is to load this module after the one |
| 65 | for your others chips. | 66 | for your others chips. |
| @@ -67,19 +68,20 @@ for your others chips. | |||
| 67 | On detection (i.e. insmod, modprobe et al.), directories are being | 68 | On detection (i.e. insmod, modprobe et al.), directories are being |
| 68 | created for each detected PCF8591: | 69 | created for each detected PCF8591: |
| 69 | 70 | ||
| 70 | /sys/bus/devices/<0>-<1>/ | 71 | /sys/bus/i2c/devices/<0>-<1>/ |
| 71 | where <0> is the bus the chip was detected on (e. g. i2c-0) | 72 | where <0> is the bus the chip was detected on (e. g. i2c-0) |
| 72 | and <1> the chip address ([48..4f]) | 73 | and <1> the chip address ([48..4f]) |
| 73 | 74 | ||
| 74 | Inside these directories, there are such files: | 75 | Inside these directories, there are such files: |
| 75 | in0, in1, in2, in3, out0_enable, out0_output, name | 76 | in0_input, in1_input, in2_input, in3_input, out0_enable, out0_output, name |
| 76 | 77 | ||
| 77 | Name contains chip name. | 78 | Name contains chip name. |
| 78 | 79 | ||
| 79 | The in0, in1, in2 and in3 files are RO. Reading gives the value of the | 80 | The in0_input, in1_input, in2_input and in3_input files are RO. Reading gives |
| 80 | corresponding channel. Depending on the current analog inputs configuration, | 81 | the value of the corresponding channel. Depending on the current analog inputs |
| 81 | files in2 and/or in3 do not exist. Values range are from 0 to 255 for single | 82 | configuration, files in2_input and in3_input may not exist. Values range |
| 82 | ended inputs and -128 to +127 for differential inputs (8-bit ADC). | 83 | from 0 to 255 for single ended inputs and -128 to +127 for differential inputs |
| 84 | (8-bit ADC). | ||
| 83 | 85 | ||
| 84 | The out0_enable file is RW. Reading gives "1" for analog output enabled and | 86 | The 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. |
