diff options
author | Lachlan McIlroy <lachlan@redback.melbourne.sgi.com> | 2008-11-28 15:23:52 +1100 |
---|---|---|
committer | Lachlan McIlroy <lachlan@redback.melbourne.sgi.com> | 2008-11-28 15:23:52 +1100 |
commit | b5a20aa2657063cbf3b47fc700603180de4bb554 (patch) | |
tree | 9419fb851cda53a7f1fd67a3697bdf8550df19e4 /Documentation/w1/masters/omap-hdq | |
parent | cc09c0dc57de7f7d2ed89d480b5653e5f6a32f2c (diff) | |
parent | ed313489badef16d700f5a3be50e8fd8f8294bc8 (diff) | |
download | op-kernel-dev-b5a20aa2657063cbf3b47fc700603180de4bb554.zip op-kernel-dev-b5a20aa2657063cbf3b47fc700603180de4bb554.tar.gz |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Diffstat (limited to 'Documentation/w1/masters/omap-hdq')
-rw-r--r-- | Documentation/w1/masters/omap-hdq | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/Documentation/w1/masters/omap-hdq b/Documentation/w1/masters/omap-hdq new file mode 100644 index 0000000..ca722e0 --- /dev/null +++ b/Documentation/w1/masters/omap-hdq @@ -0,0 +1,46 @@ +Kernel driver for omap HDQ/1-wire module. +======================================== + +Supported chips: +================ + HDQ/1-wire controller on the TI OMAP 2430/3430 platforms. + +A useful link about HDQ basics: +=============================== +http://focus.ti.com/lit/an/slua408/slua408.pdf + +Description: +============ +The HDQ/1-Wire module of TI OMAP2430/3430 platforms implement the hardware +protocol of the master functions of the Benchmark HDQ and the Dallas +Semiconductor 1-Wire protocols. These protocols use a single wire for +communication between the master (HDQ/1-Wire controller) and the slave +(HDQ/1-Wire external compliant device). + +A typical application of the HDQ/1-Wire module is the communication with battery +monitor (gas gauge) integrated circuits. + +The controller supports operation in both HDQ and 1-wire mode. The essential +difference between the HDQ and 1-wire mode is how the slave device responds to +initialization pulse.In HDQ mode, the firmware does not require the host to +create an initialization pulse to the slave.However, the slave can be reset by +using an initialization pulse (also referred to as a break pulse).The slave +does not respond with a presence pulse as it does in the 1-Wire protocol. + +Remarks: +======== +The driver (drivers/w1/masters/omap_hdq.c) supports the HDQ mode of the +controller. In this mode, as we can not read the ID which obeys the W1 +spec(family:id:crc), a module parameter can be passed to the driver which will +be used to calculate the CRC and pass back an appropriate slave ID to the W1 +core. + +By default the master driver and the BQ slave i/f +driver(drivers/w1/slaves/w1_bq27000.c) sets the ID to 1. +Please note to load both the modules with a different ID if required, but note +that the ID used should be same for both master and slave driver loading. + +e.g: +insmod omap_hdq.ko W1_ID=2 +inamod w1_bq27000.ko F_ID=2 + |