w1: masters: omap_hdq: add support for 1-wire mode

This patches makes following changes to omap_hdq driver
 - Enable 1-wire mode.
 - Implement w1_triplet callback to facilitate search rom
   procedure and auto detection of 1-wire slaves.
 - Proper enabling and disabling of interrupt.
 - Cleanups (formatting and return value checks).

HDQ mode remains unchanged.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Kumar Gala <galak@codeaurora.org>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Jonathan Corbet <corbet@lwn.net>
CC: Tony Lindgren <tony@atomide.com>
Cc: Vignesh R <vigneshr@ti.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/w1/omap-hdq.txt

 * OMAP HDQ One wire bus master controller
 
 Required properties:
-- compatible : should be "ti,omap3-1w"
+- compatible : should be "ti,omap3-1w" or "ti,am4372-hdq"
 - reg : Address and length of the register set for the device
 - interrupts : interrupt line.
 - ti,hwmods : "hdq1w"
 
+Optional properties:
+- ti,mode: should be "hdq": HDQ mode  "1w": one-wire mode.
+	   If not specified HDQ mode is implied.
+
 Example:
 
 - From omap3.dtsi
@@ -14,4 +18,5 @@ Example:
 	reg = <0x480b2000 0x1000>;
 	interrupts = <58>;
 	ti,hwmods = "hdq1w";
+	ti,mode = "hdq";
   };

Documentation/w1/masters/omap-hdq

@@ -44,3 +44,9 @@ e.g:
 insmod omap_hdq.ko W1_ID=2
 inamod w1_bq27000.ko F_ID=2
 
+The driver also supports 1-wire mode. In this mode, there is no need to
+pass slave ID as parameter. The driver will auto-detect slaves connected
+to the bus using SEARCH_ROM procedure. 1-wire mode can be selected by
+setting "ti,mode" property to "1w" in DT (see
+Documentation/devicetree/bindings/w1/omap-hdq.txt for more details).
+By default driver is in HDQ mode.