projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 17fecb55 ML |
1 | Kernel driver w1_ds2423 |
| 2 | ======================= | |
| 3 | ||
| 4 | Supported chips: | |
| 5 | * Maxim DS2423 based counter devices. | |
| 6 | ||
| 7 | supported family codes: | |
| 8 | W1_THERM_DS2423 0x1D | |
| 9 | ||
| 10 | Author: Mika Laitio <lamikr@pilppa.org> | |
| 11 | ||
| 12 | Description | |
| 13 | ----------- | |
| 14 | ||
| 15 | Support is provided through the sysfs w1_slave file. Each opening and | |
| 16 | read sequence of w1_slave file initiates the read of counters and ram | |
| 17 | available in DS2423 pages 12 - 15. | |
| 18 | ||
| 19 | Result of each page is provided as an ASCII output where each counter | |
| 20 | value and associated ram buffer is outpputed to own line. | |
| 21 | ||
| 22 | Each lines will contain the values of 42 bytes read from the counter and | |
| 23 | memory page along the crc=YES or NO for indicating whether the read operation | |
| 25985edc LDM |
24 | was successful and CRC matched. |
| 25 | If the operation was successful, there is also in the end of each line | |
| 17fecb55 ML |
26 | a counter value expressed as an integer after c= |
| 27 | ||
| 28 | Meaning of 42 bytes represented is following: | |
| 29 | - 1 byte from ram page | |
| 30 | - 4 bytes for the counter value | |
| 31 | - 4 zero bytes | |
| 32 | - 2 bytes for crc16 which was calculated from the data read since the previous crc bytes | |
| 33 | - 31 remaining bytes from the ram page | |
| 34 | - crc=YES/NO indicating whether read was ok and crc matched | |
| 35 | - c=<int> current counter value | |
| 36 | ||
| 25985edc | 37 | example from the successful read: |
| 17fecb55 ML |
38 | 00 02 00 00 00 00 00 00 00 6d 38 00 ff ff 00 00 fe ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2 |
| 39 | 00 02 00 00 00 00 00 00 00 e0 1f 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2 | |
| 40 | 00 29 c6 5d 18 00 00 00 00 04 37 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=408798761 | |
| 41 | 00 05 00 00 00 00 00 00 00 8d 39 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff crc=YES c=5 | |
| 42 | ||
| 43 | example from the read with crc errors: | |
| 44 | 00 02 00 00 00 00 00 00 00 6d 38 00 ff ff 00 00 fe ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2 | |
| 45 | 00 02 00 00 22 00 00 00 00 e0 1f 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=NO | |
| 46 | 00 e1 61 5d 19 00 00 00 00 df 0b 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=NO | |
| 47 | 00 05 00 00 20 00 00 00 00 8d 39 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff crc=NO |