On Tue, Jun 04, 2013 at 09:14:47AM +0200, Arnaud Ebalard wrote: > > Signed-off-by: Arnaud Ebalard <arno@xxxxxxxxxxxx> Please merge the patches into one. I don't see the benefit of having three patches as it is all part of one driver. Thanks, Guenter > --- > Documentation/hwmon/g762 | 62 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 62 insertions(+) > create mode 100644 Documentation/hwmon/g762 > > diff --git a/Documentation/hwmon/g762 b/Documentation/hwmon/g762 > new file mode 100644 > index 0000000..8cdb0dc > --- /dev/null > +++ b/Documentation/hwmon/g762 > @@ -0,0 +1,62 @@ > +Kernel driver g762 > +================== > + > +The GMT G762 Fan Speed PWM Controller is connected directly to a fan > +and performs closed-loop or open-loop control of the fan speed. Two > +modes - PWM or DC - are supported by the device. > + > +For additional information, a detailed datasheet is available at > +http://natisbad.org/NAS/ref/GMT_EDS-762_763-080710-0.2.pdf. sysfs > +bindings are described in Documentation/hwmon/sysfs-interface. > + > +The following entries are available to the user in a subdirectory of > +/sys/bus/i2c/drivers/g762/ to control the operation of the device. > +This can be done manually using the following entries but is usually > +done via a userland daemon like fancontrol. > + > +Note that those entries do not provide ways to setup the specific > +hardware characteristics of the system (reference clock, pulses per > +fan revolution, ...); Those can be modified via devicetree bindings > +documented in Documentation/devicetree/bindings/hwmon/g762.txt or > +using a specific platform_data structure in board initialization > +file (see include/linux/platform_data/g762.h). > + > + fan1_target: set desired fan speed. This only makes sense in closed-loop > + fan speed control (i.e. when pwm1_enable is set to 2). > + > + fan1_input: provide current fan rotation value in RPM as reported by > + the fan to the device. > + > + fan1_div: fan clock divisor. Supported value are 1, 2, 4 and 8. > + > + fan1_fault: reports fan failure, i.e. no transition on fan gear pin for > + about 0.7s (if the fan is not voluntarily set off). > + > + fan1_alarm: in closed-loop control mode, if fan RPM value is 25% out > + of the programmed value for over 6 seconds 'fan1_alarm' is > + set to 1. > + > + pwm1_enable: set current fan speed control mode i.e. 1 for manual fan > + speed control (open-loop) via pwm1 described below, 2 for > + automatic fan speed control (closed-loop) via fan1_target > + above (pwm1 is also usable). > + > + pwm1_mode: set or get fan driving mode: 1 for PWM mode, 0 for DC mode. > + > + pwm1: get or set PWM fan control value in open-loop mode. This is an > + integer value between 0 and 255. 0 stops the fan, 255 makes > + it run at full speed. > + > +Both in PWM mode ('pwm1_mode' set to 1) and DC mode ('pwm1_mode' set to 0), > +when current fan speed control mode is open-loop ('pwm1_enable' set to 1), > +the fan speed is programmed by setting a value between 0 and 255 via 'pwm1' > +entry (0 stops the fan, 255 makes it run at full speed). In closed-loop mode > +('pwm1_enable' set to 2), the expected rotation speed in RPM can be passed to > +the chip via 'fan1_target'. In closed-loop mode, the target speed is compared > +with current speed (available via 'fan1_input') by the device and a feedback > +is performed to match that target value. The fan speed value is computed > +based on the parameters associated with the physical characteristics of the > +system: a reference clock source frequency, a number of pulses per fan > +revolution, etc. > + > +Note that the driver will update its values at most once per second. > -- > 1.7.10.4 > > -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
