[PATCH] ARM: OMAP: ads7846 updates, mostly for hwmon

The ads784x chips include not just touchscreen sensors but also temperature
and voltage sensors, which are traditional hwmon fodder.

 - Register with the hwmon framework
    * hwmon needs to use subsys_init() so it's available early enough
 - Adopt hwmon convention for presenting voltages:
    * Report voltages in millivolts
    * Attribute names are "in[0-8]_input" (meaningless, ugh)
 - Be more accurate for the hwmon values:
    * vBATT gets range-adjusted
    * Discard the extra bit sent before the sample.

Battery measurements help during battery recharge monitoring.  On OSK/Mistral,
the measured voltage agreed with a multimeter until the fourth decimal place.

NOTE:  this version is only for the OMAP tree, which has some byteswap bugs
(and other changes) that are not found in the upstream kernels.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>

drivers/hwmon/hwmon.c

@@ -101,7 +101,7 @@ static void __exit hwmon_exit(void)
 	class_destroy(hwmon_class);
 }
 
-module_init(hwmon_init);
+subsys_initcall(hwmon_init);
 module_exit(hwmon_exit);
 
 EXPORT_SYMBOL_GPL(hwmon_device_register);

drivers/input/touchscreen/Kconfig

@@ -14,10 +14,13 @@ if INPUT_TOUCHSCREEN
 config TOUCHSCREEN_ADS7846
 	tristate "ADS 7846 based touchscreens"
 	depends on SPI_MASTER
+	select HWMON
 	help
 	  Say Y here if you have a touchscreen interface using the
 	  ADS7846 controller, and your board-specific initialization
-	  code includes that in its table of SPI devices.
+	  code includes that in its table of SPI devices.  You will
+	  also get hwmon interfaces for the temperature and voltage
+	  sensors this chip provides.
 
 	  If unsure, say N (but it's safe to say "Y").