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| author | Herbert Valerio Riedel <hvr@gnu.org> | 2009-04-06 19:00:30 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-07 08:31:03 -0700 |
| commit | 3bcfa9e47a7d1be6faef3be6c4b2049e585e2f38 (patch) | |
| tree | 7cc0896fb4ee501fb08560adc1747b7e5a7544cf /Documentation/hwmon/g760a | |
| parent | 6260a4b0521a41189b2c2a8119096c1e21dbdf2c (diff) | |
| download | blackbird-op-linux-3bcfa9e47a7d1be6faef3be6c4b2049e585e2f38.tar.gz blackbird-op-linux-3bcfa9e47a7d1be6faef3be6c4b2049e585e2f38.zip | |
hwmon: add support for GMT G760A fan speed PWM controller
This controller can be found on the D-Link DNS-323 for instance, where
it is to be configured via static i2c_board_info in the board-specific
mach-orion/dns323-setup.c; this driver supports only the new-style
driver model.
Tested-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>
Signed-off-by: Matthew Palmer <mpalmer@debian.org>
Signed-off-by: Laurie Bradshaw <bradshaw.laurie@googlemail.com>
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/hwmon/g760a')
| -rw-r--r-- | Documentation/hwmon/g760a | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/Documentation/hwmon/g760a b/Documentation/hwmon/g760a new file mode 100644 index 000000000000..e032eeb75629 --- /dev/null +++ b/Documentation/hwmon/g760a @@ -0,0 +1,36 @@ +Kernel driver g760a +=================== + +Supported chips: + * Global Mixed-mode Technology Inc. G760A + Prefix: 'g760a' + Datasheet: Publicly available at the GMT website + http://www.gmt.com.tw/datasheet/g760a.pdf + +Author: Herbert Valerio Riedel <hvr@gnu.org> + +Description +----------- + +The GMT G760A Fan Speed PWM Controller is connected directly to a fan +and performs closed-loop control of the fan speed. + +The fan speed is programmed by setting the period via 'pwm1' of two +consecutive speed pulses. The period is defined in terms of clock +cycle counts of an assumed 32kHz clock source. + +Setting a period of 0 stops the fan; setting the period to 255 sets +fan to maximum speed. + +The measured fan rotation speed returned via 'fan1_input' is derived +from the measured speed pulse period by assuming again a 32kHz clock +source and a 2 pulse-per-revolution fan. + +The 'alarms' file provides access to the two alarm bits provided by +the G760A chip's status register: Bit 0 is set when the actual fan +speed differs more than 20% with respect to the programmed fan speed; +bit 1 is set when fan speed is below 1920 RPM. + +The g760a driver will not update its values more frequently than every +other second; reading them more often will do no harm, but will return +'old' values. |
