| Markus Franke | fbf7f7b | 2012-05-26 00:45:12 +0200 | [diff] [blame] | 1 | Kernel driver w1_ds28e04 |
| 2 | ======================== |
| 3 | |
| 4 | Supported chips: |
| 5 | * Maxim DS28E04-100 4096-Bit Addressable 1-Wire EEPROM with PIO |
| 6 | |
| 7 | supported family codes: |
| 8 | W1_FAMILY_DS28E04 0x1C |
| 9 | |
| 10 | Author: Markus Franke, <franke.m@sebakmt.com> <franm@hrz.tu-chemnitz.de> |
| 11 | |
| 12 | Description |
| 13 | ----------- |
| 14 | |
| 15 | Support is provided through the sysfs files "eeprom" and "pio". CRC checking |
| 16 | during memory accesses can optionally be enabled/disabled via the device |
| 17 | attribute "crccheck". The strong pull-up can optionally be enabled/disabled |
| 18 | via the module parameter "w1_strong_pullup". |
| 19 | |
| 20 | Memory Access |
| 21 | |
| 22 | A read operation on the "eeprom" file reads the given amount of bytes |
| 23 | from the EEPROM of the DS28E04. |
| 24 | |
| 25 | A write operation on the "eeprom" file writes the given byte sequence |
| 26 | to the EEPROM of the DS28E04. If CRC checking mode is enabled only |
| Anatol Pomozov | f884ab1 | 2013-05-08 16:56:16 -0700 | [diff] [blame] | 27 | fully aligned blocks of 32 bytes with valid CRC16 values (in bytes 30 |
| Markus Franke | fbf7f7b | 2012-05-26 00:45:12 +0200 | [diff] [blame] | 28 | and 31) are allowed to be written. |
| 29 | |
| 30 | PIO Access |
| 31 | |
| 32 | The 2 PIOs of the DS28E04-100 are accessible via the "pio" sysfs file. |
| 33 | |
| 34 | The current status of the PIO's is returned as an 8 bit value. Bit 0/1 |
| 35 | represent the state of PIO_0/PIO_1. Bits 2..7 do not care. The PIO's are |
| 36 | driven low-active, i.e. the driver delivers/expects low-active values. |