Commit | Line | Data |
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e0a29382 MC |
1 | Kernel driver for omap HDQ/1-wire module. |
2 | ======================================== | |
3 | ||
4 | Supported chips: | |
5 | ================ | |
6 | HDQ/1-wire controller on the TI OMAP 2430/3430 platforms. | |
7 | ||
8 | A useful link about HDQ basics: | |
9 | =============================== | |
0ea6e611 | 10 | http://focus.ti.com/lit/an/slua408a/slua408a.pdf |
e0a29382 MC |
11 | |
12 | Description: | |
13 | ============ | |
14 | The HDQ/1-Wire module of TI OMAP2430/3430 platforms implement the hardware | |
15 | protocol of the master functions of the Benchmark HDQ and the Dallas | |
16 | Semiconductor 1-Wire protocols. These protocols use a single wire for | |
17 | communication between the master (HDQ/1-Wire controller) and the slave | |
18 | (HDQ/1-Wire external compliant device). | |
19 | ||
20 | A typical application of the HDQ/1-Wire module is the communication with battery | |
21 | monitor (gas gauge) integrated circuits. | |
22 | ||
23 | The controller supports operation in both HDQ and 1-wire mode. The essential | |
24 | difference between the HDQ and 1-wire mode is how the slave device responds to | |
25 | initialization pulse.In HDQ mode, the firmware does not require the host to | |
26 | create an initialization pulse to the slave.However, the slave can be reset by | |
27 | using an initialization pulse (also referred to as a break pulse).The slave | |
28 | does not respond with a presence pulse as it does in the 1-Wire protocol. | |
29 | ||
30 | Remarks: | |
31 | ======== | |
32 | The driver (drivers/w1/masters/omap_hdq.c) supports the HDQ mode of the | |
33 | controller. In this mode, as we can not read the ID which obeys the W1 | |
34 | spec(family:id:crc), a module parameter can be passed to the driver which will | |
35 | be used to calculate the CRC and pass back an appropriate slave ID to the W1 | |
36 | core. | |
37 | ||
38 | By default the master driver and the BQ slave i/f | |
39 | driver(drivers/w1/slaves/w1_bq27000.c) sets the ID to 1. | |
40 | Please note to load both the modules with a different ID if required, but note | |
41 | that the ID used should be same for both master and slave driver loading. | |
42 | ||
43 | e.g: | |
44 | insmod omap_hdq.ko W1_ID=2 | |
45 | inamod w1_bq27000.ko F_ID=2 | |
46 |