1e9bb6275SMauro Carvalho Chehab======================== 2e9bb6275SMauro Carvalho ChehabKernel driver w1_ds28e04 3e9bb6275SMauro Carvalho Chehab======================== 4e9bb6275SMauro Carvalho Chehab 5e9bb6275SMauro Carvalho ChehabSupported chips: 6e9bb6275SMauro Carvalho Chehab 7e9bb6275SMauro Carvalho Chehab * Maxim DS28E04-100 4096-Bit Addressable 1-Wire EEPROM with PIO 8e9bb6275SMauro Carvalho Chehab 9e9bb6275SMauro Carvalho Chehabsupported family codes: 10e9bb6275SMauro Carvalho Chehab 11e9bb6275SMauro Carvalho Chehab ================= ==== 12e9bb6275SMauro Carvalho Chehab W1_FAMILY_DS28E04 0x1C 13e9bb6275SMauro Carvalho Chehab ================= ==== 14e9bb6275SMauro Carvalho Chehab 15e9bb6275SMauro Carvalho ChehabAuthor: Markus Franke, <franke.m@sebakmt.com> <franm@hrz.tu-chemnitz.de> 16e9bb6275SMauro Carvalho Chehab 17e9bb6275SMauro Carvalho ChehabDescription 18e9bb6275SMauro Carvalho Chehab----------- 19e9bb6275SMauro Carvalho Chehab 20e9bb6275SMauro Carvalho ChehabSupport is provided through the sysfs files "eeprom" and "pio". CRC checking 21e9bb6275SMauro Carvalho Chehabduring memory accesses can optionally be enabled/disabled via the device 22e9bb6275SMauro Carvalho Chehabattribute "crccheck". The strong pull-up can optionally be enabled/disabled 23e9bb6275SMauro Carvalho Chehabvia the module parameter "w1_strong_pullup". 24e9bb6275SMauro Carvalho Chehab 25e9bb6275SMauro Carvalho ChehabMemory Access 26e9bb6275SMauro Carvalho Chehab 27e9bb6275SMauro Carvalho Chehab A read operation on the "eeprom" file reads the given amount of bytes 28e9bb6275SMauro Carvalho Chehab from the EEPROM of the DS28E04. 29e9bb6275SMauro Carvalho Chehab 30e9bb6275SMauro Carvalho Chehab A write operation on the "eeprom" file writes the given byte sequence 31e9bb6275SMauro Carvalho Chehab to the EEPROM of the DS28E04. If CRC checking mode is enabled only 32e9bb6275SMauro Carvalho Chehab fully aligned blocks of 32 bytes with valid CRC16 values (in bytes 30 33e9bb6275SMauro Carvalho Chehab and 31) are allowed to be written. 34e9bb6275SMauro Carvalho Chehab 35e9bb6275SMauro Carvalho ChehabPIO Access 36e9bb6275SMauro Carvalho Chehab 37e9bb6275SMauro Carvalho Chehab The 2 PIOs of the DS28E04-100 are accessible via the "pio" sysfs file. 38e9bb6275SMauro Carvalho Chehab 39e9bb6275SMauro Carvalho Chehab The current status of the PIO's is returned as an 8 bit value. Bit 0/1 40e9bb6275SMauro Carvalho Chehab represent the state of PIO_0/PIO_1. Bits 2..7 do not care. The PIO's are 41e9bb6275SMauro Carvalho Chehab driven low-active, i.e. the driver delivers/expects low-active values. 42