[PATCH] I2C: documentation update 2/3
This patch adds missing documentation for system health monitoring chips.
I would like to thank all people, who helped me with this project.
Signed-off-by: Rudolf Marek <r.marek@sh.cvut.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/Documentation/i2c/chips/it87 b/Documentation/i2c/chips/it87
new file mode 100644
index 0000000..0d01950
--- /dev/null
+++ b/Documentation/i2c/chips/it87
@@ -0,0 +1,96 @@
+Kernel driver it87
+==================
+
+Supported chips:
+ * IT8705F
+ Prefix: 'it87'
+ Addresses scanned: from Super I/O config space, or default ISA 0x290 (8 I/O ports)
+ Datasheet: Publicly available at the ITE website
+ http://www.ite.com.tw/
+ * IT8712F
+ Prefix: 'it8712'
+ Addresses scanned: I2C 0x28 - 0x2f
+ from Super I/O config space, or default ISA 0x290 (8 I/O ports)
+ Datasheet: Publicly available at the ITE website
+ http://www.ite.com.tw/
+ * SiS950 [clone of IT8705F]
+ Prefix: 'sis950'
+ Addresses scanned: from Super I/O config space, or default ISA 0x290 (8 I/O ports)
+ Datasheet: No longer be available
+
+Author: Christophe Gauthron <chrisg@0-in.com>
+
+
+Module Parameters
+-----------------
+
+* update_vbat: int
+
+ 0 if vbat should report power on value, 1 if vbat should be updated after
+ each read. Default is 0. On some boards the battery voltage is provided
+ by either the battery or the onboard power supply. Only the first reading
+ at power on will be the actual battery voltage (which the chip does
+ automatically). On other boards the battery voltage is always fed to
+ the chip so can be read at any time. Excessive reading may decrease
+ battery life but no information is given in the datasheet.
+
+* fix_pwm_polarity int
+
+ Force PWM polarity to active high (DANGEROUS). Some chips are
+ misconfigured by BIOS - PWM values would be inverted. This option tries
+ to fix this. Please contact your BIOS manufacturer and ask him for fix.
+
+Description
+-----------
+
+This driver implements support for the IT8705F, IT8712F and SiS950 chips.
+
+This driver also supports IT8712F, which adds SMBus access, and a VID
+input, used to report the Vcore voltage of the Pentium processor.
+The IT8712F additionally features VID inputs.
+
+These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
+joysticks and other miscellaneous stuff. For hardware monitoring, they
+include an 'environment controller' with 3 temperature sensors, 3 fan
+rotation speed sensors, 8 voltage sensors, and associated alarms.
+
+Temperatures are measured in degrees Celsius. An alarm is triggered once
+when the Overtemperature Shutdown limit is crossed.
+
+Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
+triggered if the rotation speed has dropped below a programmable limit. Fan
+readings can be divided by a programmable divider (1, 2, 4 or 8) to give the
+readings more range or accuracy. Not all RPM values can accurately be
+represented, so some rounding is done. With a divider of 2, the lowest
+representable value is around 2600 RPM.
+
+Voltage sensors (also known as IN sensors) report their values in volts. An
+alarm is triggered if the voltage has crossed a programmable minimum or
+maximum limit. Note that minimum in this case always means 'closest to
+zero'; this is important for negative voltage measurements. All voltage
+inputs can measure voltages between 0 and 4.08 volts, with a resolution of
+0.016 volt. The battery voltage in8 does not have limit registers.
+
+The VID lines (IT8712F only) encode the core voltage value: the voltage
+level your processor should work with. This is hardcoded by the mainboard
+and/or processor itself. It is a value in volts.
+
+If an alarm triggers, it will remain triggered until the hardware register
+is read at least once. This means that the cause for the alarm may already
+have disappeared! Note that in the current implementation, all hardware
+registers are read whenever any data is read (unless it is less than 1.5
+seconds since the last update). This means that you can easily miss
+once-only alarms.
+
+The IT87xx only updates its values each 1.5 seconds; reading it more often
+will do no harm, but will return 'old' values.
+
+To change sensor N to a thermistor, 'echo 2 > tempN_type' where N is 1, 2,
+or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'.
+Give 0 for unused sensor. Any other value is invalid. To configure this at
+startup, consult lm_sensors's /etc/sensors.conf. (2 = thermistor;
+3 = thermal diode)
+
+The fan speed control features are limited to manual PWM mode. Automatic
+"Smart Guardian" mode control handling is not implemented. However
+if you want to go for "manual mode" just write 1 to pwmN_enable.