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authorDavid Woodhouse <dwmw2@shinybook.infradead.org>2005-07-02 13:39:09 +0100
committerDavid Woodhouse <dwmw2@shinybook.infradead.org>2005-07-02 13:39:09 +0100
commitd2f6409584e2c62ffad81690562330ff3bf4a458 (patch)
tree3bdfb97d0b51be2f7f414f2107e97603c1206abb /Documentation/i2c/chips/via686a
parente1b09eba2686eca94a3a188042b518df6044a3c1 (diff)
parent4a89a04f1ee21a7c1f4413f1ad7dcfac50ff9b63 (diff)
Merge with master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
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+Kernel driver via686a
+=====================
+
+Supported chips:
+ * Via VT82C686A, VT82C686B Southbridge Integrated Hardware Monitor
+ Prefix: 'via686a'
+ Addresses scanned: ISA in PCI-space encoded address
+ Datasheet: On request through web form (http://www.via.com.tw/en/support/datasheets/)
+
+Authors:
+ Kyösti Mälkki <kmalkki@cc.hut.fi>,
+ Mark D. Studebaker <mdsxyz123@yahoo.com>
+ Bob Dougherty <bobd@stanford.edu>
+ (Some conversion-factor data were contributed by
+ Jonathan Teh Soon Yew <j.teh@iname.com>
+ and Alex van Kaam <darkside@chello.nl>.)
+
+Module Parameters
+-----------------
+
+force_addr=0xaddr Set the I/O base address. Useful for Asus A7V boards
+ that don't set the address in the BIOS. Does not do a
+ PCI force; the via686a must still be present in lspci.
+ Don't use this unless the driver complains that the
+ base address is not set.
+ Example: 'modprobe via686a force_addr=0x6000'
+
+Description
+-----------
+
+The driver does not distinguish between the chips and reports
+all as a 686A.
+
+The Via 686a southbridge has integrated hardware monitor functionality.
+It also has an I2C bus, but this driver only supports the hardware monitor.
+For the I2C bus driver, see <file:Documentation/i2c/busses/i2c-viapro>
+
+The Via 686a implements three temperature sensors, two fan rotation speed
+sensors, five voltage sensors and alarms.
+
+Temperatures are measured in degrees Celsius. An alarm is triggered once
+when the Overtemperature Shutdown limit is crossed; it is triggered again
+as soon as it drops below the hysteresis value.
+
+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. Voltages are internally scalled, so each voltage channel
+has a different resolution and range.
+
+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 driver only updates its values each 1.5 seconds; reading it more often
+will do no harm, but will return 'old' values.