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Based on kernel version 4.13.3. Page generated on 2017-09-23 13:56 EST.

1	Kernel driver for omap HDQ/1-wire module.
2	========================================
4	Supported chips:
5	================
6		HDQ/1-wire controller on the TI OMAP 2430/3430 platforms.
8	A useful link about HDQ basics:
9	===============================
10	http://focus.ti.com/lit/an/slua408a/slua408a.pdf
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).
20	A typical application of the HDQ/1-Wire module is the communication with battery
21	monitor (gas gauge) integrated circuits.
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.
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.
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.
43	e.g:
44	insmod omap_hdq.ko W1_ID=2
45	inamod w1_bq27000.ko F_ID=2
47	The driver also supports 1-wire mode. In this mode, there is no need to
48	pass slave ID as parameter. The driver will auto-detect slaves connected
49	to the bus using SEARCH_ROM procedure. 1-wire mode can be selected by
50	setting "ti,mode" property to "1w" in DT (see
51	Documentation/devicetree/bindings/w1/omap-hdq.txt for more details).
52	By default driver is in HDQ mode.
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