Commit | Line | Data |
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b4c9c1a7 GR |
1 | Kernel driver adc128d818 |
2 | ======================== | |
3 | ||
4 | Supported chips: | |
b04f2f7d | 5 | |
b4c9c1a7 | 6 | * Texas Instruments ADC818D818 |
b04f2f7d | 7 | |
b4c9c1a7 | 8 | Prefix: 'adc818d818' |
b04f2f7d | 9 | |
b4c9c1a7 | 10 | Addresses scanned: I2C 0x1d, 0x1e, 0x1f, 0x2d, 0x2e, 0x2f |
b04f2f7d | 11 | |
ad736c1a | 12 | Datasheet: Publicly available at the TI website https://www.ti.com/ |
b4c9c1a7 GR |
13 | |
14 | Author: Guenter Roeck | |
15 | ||
16 | Description | |
17 | ----------- | |
18 | ||
19 | This driver implements support for the Texas Instruments ADC128D818. | |
20 | It is described as 'ADC System Monitor with Temperature Sensor'. | |
21 | ||
22 | The ADC128D818 implements one temperature sensor and seven voltage sensors. | |
23 | ||
24 | Temperatures are measured in degrees Celsius. There is one set of limits. | |
25 | When the HOT Temperature Limit is crossed, this will cause an alarm that will | |
26 | be reasserted until the temperature drops below the HOT Hysteresis. | |
27 | Measurements are guaranteed between -55 and +125 degrees. The temperature | |
28 | measurement has a resolution of 0.5 degrees; the limits have a resolution | |
29 | of 1 degree. | |
30 | ||
31 | Voltage sensors (also known as IN sensors) report their values in volts. | |
32 | An alarm is triggered if the voltage has crossed a programmable minimum | |
33 | or maximum limit. Note that minimum in this case always means 'closest to | |
34 | zero'; this is important for negative voltage measurements. All voltage | |
35 | inputs can measure voltages between 0 and 2.55 volts, with a resolution | |
36 | of 0.625 mV. | |
37 | ||
38 | If an alarm triggers, it will remain triggered until the hardware register | |
39 | is read at least once. This means that the cause for the alarm may | |
40 | already have disappeared by the time the alarm is read. The driver | |
41 | caches the alarm status for each sensor until it is at least reported | |
42 | once, to ensure that alarms are reported to user space. | |
43 | ||
44 | The ADC128D818 only updates its values approximately once per second; | |
45 | reading it more often will do no harm, but will return 'old' values. | |
46 | ||
47 | In addition to the scanned address list, the chip can also be configured for | |
48 | addresses 0x35 to 0x37. Those addresses are not scanned. You have to instantiate | |
49 | the driver explicitly if the chip is configured for any of those addresses in | |
50 | your system. |