w1: Add 1-wire slave device driver for DS28E04-100

Signed-off-by: Markus Franke <franm@hrz.tu-chemnitz.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/stable/sysfs-driver-w1_ds28e04

@@ -0,0 +1,15 @@
+What:		/sys/bus/w1/devices/.../pio
+Date:		May 2012
+Contact:	Markus Franke <franm@hrz.tu-chemnitz.de>
+Description:	read/write the contents of the two PIO's of the DS28E04-100
+		see Documentation/w1/slaves/w1_ds28e04 for detailed information
+Users:		any user space application which wants to communicate with DS28E04-100
+
+
+
+What:		/sys/bus/w1/devices/.../eeprom
+Date:		May 2012
+Contact:	Markus Franke <franm@hrz.tu-chemnitz.de>
+Description:	read/write the contents of the EEPROM memory of the DS28E04-100
+		see Documentation/w1/slaves/w1_ds28e04 for detailed information
+Users:		any user space application which wants to communicate with DS28E04-100

Documentation/w1/slaves/w1_ds28e04

@@ -0,0 +1,36 @@
+Kernel driver w1_ds28e04
+========================
+
+Supported chips:
+  * Maxim DS28E04-100 4096-Bit Addressable 1-Wire EEPROM with PIO
+
+supported family codes:
+	W1_FAMILY_DS28E04	0x1C
+
+Author: Markus Franke, <franke.m@sebakmt.com> <franm@hrz.tu-chemnitz.de>
+
+Description
+-----------
+
+Support is provided through the sysfs files "eeprom" and "pio". CRC checking
+during memory accesses can optionally be enabled/disabled via the device
+attribute "crccheck". The strong pull-up can optionally be enabled/disabled
+via the module parameter "w1_strong_pullup".
+
+Memory Access
+
+	A read operation on the "eeprom" file reads the given amount of bytes
+	from the EEPROM of the DS28E04.
+
+	A write operation on the "eeprom" file writes the given byte sequence
+	to the EEPROM of the DS28E04. If CRC checking mode is enabled only
+	fully alligned blocks of 32 bytes with valid CRC16 values (in bytes 30
+	and 31) are allowed to be written.
+
+PIO Access
+
+	The 2 PIOs of the DS28E04-100 are accessible via the "pio" sysfs file.
+
+	The current status of the PIO's is returned as an 8 bit value. Bit 0/1
+	represent the state of PIO_0/PIO_1. Bits 2..7 do not care. The PIO's are
+	driven low-active, i.e. the driver delivers/expects low-active values.

drivers/w1/slaves/Kconfig

@@ -94,6 +94,19 @@ config W1_SLAVE_DS2781
 
 	  If you are unsure, say N.
 
+config W1_SLAVE_DS28E04
+	tristate "4096-Bit Addressable 1-Wire EEPROM with PIO (DS28E04-100)"
+	depends on W1
+	select CRC16
+	help
+	  If you enable this you will have the DS28E04-100
+	  chip support.
+
+	  Say Y here if you want to use a 1-wire
+	  4kb EEPROM with PIO family device (DS28E04).
+
+	  If you are unsure, say N.
+
 config W1_SLAVE_BQ27000
 	tristate "BQ27000 slave support"
 	depends on W1

drivers/w1/slaves/Makefile

@@ -12,3 +12,4 @@ obj-$(CONFIG_W1_SLAVE_DS2760)	+= w1_ds2760.o
 obj-$(CONFIG_W1_SLAVE_DS2780)	+= w1_ds2780.o
 obj-$(CONFIG_W1_SLAVE_DS2781)	+= w1_ds2781.o
 obj-$(CONFIG_W1_SLAVE_BQ27000)	+= w1_bq27000.o
+obj-$(CONFIG_W1_SLAVE_DS28E04)	+= w1_ds28e04.o