| Mauro Carvalho Chehab | e9bb627 | 2019-07-31 17:08:53 -0300 | [diff] [blame] | 1 | Kernel driver w1_ds2423 |
| 2 | ======================= |
| 3 | |
| 4 | Supported chips: |
| 5 | |
| 6 | * Maxim DS2423 based counter devices. |
| 7 | |
| 8 | supported family codes: |
| 9 | |
| 10 | =============== ==== |
| 11 | W1_THERM_DS2423 0x1D |
| 12 | =============== ==== |
| 13 | |
| 14 | Author: Mika Laitio <lamikr@pilppa.org> |
| 15 | |
| 16 | Description |
| 17 | ----------- |
| 18 | |
| 19 | Support is provided through the sysfs w1_slave file. Each opening and |
| 20 | read sequence of w1_slave file initiates the read of counters and ram |
| 21 | available in DS2423 pages 12 - 15. |
| 22 | |
| 23 | Result of each page is provided as an ASCII output where each counter |
| 24 | value and associated ram buffer is outpputed to own line. |
| 25 | |
| 26 | Each lines will contain the values of 42 bytes read from the counter and |
| 27 | memory page along the crc=YES or NO for indicating whether the read operation |
| 28 | was successful and CRC matched. |
| 29 | If the operation was successful, there is also in the end of each line |
| 30 | a counter value expressed as an integer after c= |
| 31 | |
| 32 | Meaning of 42 bytes represented is following: |
| 33 | |
| 34 | - 1 byte from ram page |
| 35 | - 4 bytes for the counter value |
| 36 | - 4 zero bytes |
| 37 | - 2 bytes for crc16 which was calculated from the data read since the previous crc bytes |
| 38 | - 31 remaining bytes from the ram page |
| 39 | - crc=YES/NO indicating whether read was ok and crc matched |
| 40 | - c=<int> current counter value |
| 41 | |
| 42 | example from the successful read:: |
| 43 | |
| 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 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 |
| 46 | 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 |
| 47 | 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 |
| 48 | |
| 49 | example from the read with crc errors:: |
| 50 | |
| 51 | 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 |
| 52 | 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 |
| 53 | 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 |
| 54 | 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 |