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kernel/linux-imx6_3.14.28/Documentation/w1/masters/omap-hdq 1.83 KB
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  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/slua408a/slua408a.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