hwmon: add support for JEDEC JC 42.4 compliant temperature sensors

[[email protected]: coding-style fixes]
Signed-off-by: Guenter Roeck <[email protected]>
Cc: Jean Delvare <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Hans de Goede <[email protected]>
Cc: Mark Brown <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Documentation/hwmon/jc42

@@ -0,0 +1,97 @@
+Kernel driver jc42
+==================
+
+Supported chips:
+  * Analog Devices ADT7408
+    Prefix: 'adt7408'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+	http://www.analog.com/static/imported-files/data_sheets/ADT7408.pdf
+  * IDT TSE2002B3, TS3000B3
+    Prefix: 'tse2002b3', 'ts3000b3'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+	http://www.idt.com/products/getdoc.cfm?docid=18715691
+	http://www.idt.com/products/getdoc.cfm?docid=18715692
+  * Maxim MAX6604
+    Prefix: 'max6604'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+	http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf
+  * Microchip MCP9805, MCP98242, MCP98243, MCP9843
+    Prefixes: 'mcp9805', 'mcp98242', 'mcp98243', 'mcp9843'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+	http://ww1.microchip.com/downloads/en/DeviceDoc/21977b.pdf
+	http://ww1.microchip.com/downloads/en/DeviceDoc/21996a.pdf
+	http://ww1.microchip.com/downloads/en/DeviceDoc/22153c.pdf
+  * NXP Semiconductors SE97, SE97B
+    Prefix: 'se97'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+	http://www.nxp.com/documents/data_sheet/SE97.pdf
+	http://www.nxp.com/documents/data_sheet/SE97B.pdf
+  * NXP Semiconductors SE98
+    Prefix: 'se98'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+	http://www.nxp.com/documents/data_sheet/SE98.pdf
+  * ON Semiconductor CAT34TS02, CAT6095
+    Prefix: 'cat34ts02', 'cat6095'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheet:
+	http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF
+	http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF
+  * ST Microelectronics STTS424, STTS424E02
+    Prefix: 'stts424'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheets:
+	http://www.st.com/stonline/products/literature/ds/13447/stts424.pdf
+	http://www.st.com/stonline/products/literature/ds/13448/stts424e02.pdf
+  * JEDEC JC 42.4 compliant temperature sensor chips
+    Prefix: 'jc42'
+    Addresses scanned: I2C 0x18 - 0x1f
+    Datasheet: -
+
+Author:
+	Guenter Roeck <[email protected]>
+
+
+Description
+-----------
+
+This driver implements support for JEDEC JC 42.4 compliant temperature sensors.
+The driver auto-detects the chips listed above, but can be manually instantiated
+to support other JC 42.4 compliant chips.
+
+Example: the following will load the driver for a generic JC 42.4 compliant
+temperature sensor at address 0x18 on I2C bus #1:
+
+# modprobe jc42
+# echo jc42 0x18 > /sys/bus/i2c/devices/i2c-1/new_device
+
+A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum,
+and critical temperature can be configured. There are alarms for high, low,
+and critical thresholds.
+
+There is also an hysteresis to control the thresholds for resetting alarms.
+Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5,
+3.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those
+limits. The chip supports only a single register to configure the hysteresis,
+which applies to all limits. This register can be written by writing into
+temp1_crit_hyst. Other hysteresis attributes are read-only.
+
+Sysfs entries
+-------------
+
+temp1_input		Temperature (RO)
+temp1_min		Minimum temperature (RW)
+temp1_max		Maximum temperature (RW)
+temp1_crit		Critical high temperature (RW)
+
+temp1_crit_hyst		Critical hysteresis temperature (RW)
+temp1_max_hyst		Maximum hysteresis temperature (RO)
+
+temp1_min_alarm		Temperature low alarm
+temp1_max_alarm		Temperature high alarm
+temp1_crit_alarm	Temperature critical alarm