projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 57d60b1b GR |
1 | Kernel driver emc1403 |
| 2 | ===================== | |
| 3 | ||
| 4 | Supported chips: | |
| b04f2f7d | 5 | |
| 57d60b1b | 6 | * SMSC / Microchip EMC1402, EMC1412 |
| b04f2f7d | 7 | |
| 57d60b1b | 8 | Addresses scanned: I2C 0x18, 0x1c, 0x29, 0x4c, 0x4d, 0x5c |
| b04f2f7d | 9 | |
| 57d60b1b | 10 | Prefix: 'emc1402' |
| b04f2f7d | 11 | |
| 57d60b1b | 12 | Datasheets: |
| b04f2f7d MCC |
13 | |
| 14 | - http://ww1.microchip.com/downloads/en/DeviceDoc/1412.pdf | |
| 15 | - http://ww1.microchip.com/downloads/en/DeviceDoc/1402.pdf | |
| 16 | ||
| 57d60b1b | 17 | * SMSC / Microchip EMC1403, EMC1404, EMC1413, EMC1414 |
| b04f2f7d | 18 | |
| 57d60b1b | 19 | Addresses scanned: I2C 0x18, 0x29, 0x4c, 0x4d |
| b04f2f7d | 20 | |
| 57d60b1b | 21 | Prefix: 'emc1403', 'emc1404' |
| b04f2f7d | 22 | |
| 57d60b1b | 23 | Datasheets: |
| b04f2f7d MCC |
24 | |
| 25 | - http://ww1.microchip.com/downloads/en/DeviceDoc/1403_1404.pdf | |
| 26 | - http://ww1.microchip.com/downloads/en/DeviceDoc/1413_1414.pdf | |
| 27 | ||
| 57d60b1b | 28 | * SMSC / Microchip EMC1422 |
| b04f2f7d | 29 | |
| 57d60b1b | 30 | Addresses scanned: I2C 0x4c |
| b04f2f7d | 31 | |
| 57d60b1b | 32 | Prefix: 'emc1422' |
| b04f2f7d | 33 | |
| 57d60b1b | 34 | Datasheet: |
| b04f2f7d MCC |
35 | |
| 36 | - http://ww1.microchip.com/downloads/en/DeviceDoc/1422.pdf | |
| 37 | ||
| 57d60b1b | 38 | * SMSC / Microchip EMC1423, EMC1424 |
| b04f2f7d | 39 | |
| 57d60b1b | 40 | Addresses scanned: I2C 0x4c |
| b04f2f7d | 41 | |
| 57d60b1b | 42 | Prefix: 'emc1423', 'emc1424' |
| b04f2f7d | 43 | |
| 57d60b1b | 44 | Datasheet: |
| b04f2f7d MCC |
45 | |
| 46 | - http://ww1.microchip.com/downloads/en/DeviceDoc/1423_1424.pdf | |
| 57d60b1b GR |
47 | |
| 48 | Author: | |
| 49 | Kalhan Trisal <kalhan.trisal@intel.com | |
| 50 | ||
| 51 | ||
| 52 | Description | |
| 53 | ----------- | |
| 54 | ||
| 55 | The Standard Microsystems Corporation (SMSC) / Microchip EMC14xx chips | |
| 56 | contain up to four temperature sensors. EMC14x2 support two sensors | |
| 57 | (one internal, one external). EMC14x3 support three sensors (one internal, | |
| 58 | two external), and EMC14x4 support four sensors (one internal, three | |
| 59 | external). | |
| 60 | ||
| 61 | The chips implement three limits for each sensor: low (tempX_min), high | |
| 62 | (tempX_max) and critical (tempX_crit.) The chips also implement an | |
| 63 | hysteresis mechanism which applies to all limits. The relative difference | |
| 64 | is stored in a single register on the chip, which means that the relative | |
| 65 | difference between the limit and its hysteresis is always the same for | |
| 66 | all three limits. | |
| 67 | ||
| 68 | This implementation detail implies the following: | |
| b04f2f7d | 69 | |
| 57d60b1b GR |
70 | * When setting a limit, its hysteresis will automatically follow, the |
| 71 | difference staying unchanged. For example, if the old critical limit | |
| 72 | was 80 degrees C, and the hysteresis was 75 degrees C, and you change | |
| 73 | the critical limit to 90 degrees C, then the hysteresis will | |
| 74 | automatically change to 85 degrees C. | |
| 84899d39 GR |
75 | * The hysteresis values can't be set independently. We decided to make |
| 76 | only temp1_crit_hyst writable, while all other hysteresis attributes | |
| 77 | are read-only. Setting temp1_crit_hyst writes the difference between | |
| 78 | temp1_crit_hyst and temp1_crit into the chip, and the same relative | |
| 79 | hysteresis applies automatically to all other limits. | |
| 57d60b1b | 80 | * The limits should be set before the hysteresis. |