This patch adds standard documentation for the userspace sysfs attributes of the Quadrature Counter interface.
Signed-off-by: William Breathitt Gray <[email protected]> --- .../ABI/testing/sysfs-bus-counter-quadrature-sysfs | 76 ++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-bus-counter-quadrature-sysfs diff --git a/Documentation/ABI/testing/sysfs-bus-counter-quadrature-sysfs b/Documentation/ABI/testing/sysfs-bus-counter-quadrature-sysfs new file mode 100644 index 000000000000..69d1a3e4a1a5 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-counter-quadrature-sysfs @@ -0,0 +1,76 @@ +What: /sys/bus/counter/devices/counterX/countY +KernelVersion: 4.16 +Contact: [email protected] +Description: + Count data of Count Y. This is a signed integer value that + represents the position. Typically, this is determined by + hardware evaluation of the quadrature encoding input signals. + +What: /sys/bus/counter/devices/counterX/countY_direction +KernelVersion: 4.16 +Contact: [email protected] +Description: + Count direction of Count Y. Typically, this is determined by + hardware evaluation of the quadrature encoding input signals. + Two count directions are available: forward and backward. + +What: /sys/bus/counter/devices/counterX/countY_function +KernelVersion: 4.16 +Contact: [email protected] +Description: + Count function mode of Count Y. Count function evaluation is + triggered by conditions specified by the countY_signalZ_action + attributes. Four count function modes are available: + pulse-direction, quadrature x1, quadrature x2, quadrature x4. + + Pulse-Direction: + Rising edges on quadrature pair signal A updates the + respective count. The input level of quadrature pair + signal B determines direction. + + Quadrature x1: + If direction is forward, rising edges on quadrature pair + signal A updates the respective count; if the direction + is backward, falling edges on quadrature pair signal A + updates the respective count. Quadrature encoding + determines the direction. + + Quadrature x2: + Any state transition on quadrature pair signal A updates + the respective count. Quadrature encoding determines the + direction. + + Quadrature x4: + Any state transition on either quadrature pair signals + updates the respective count. Quadrature encoding + determines the direction. + +What: /sys/bus/counter/devices/counterX/countY_signalZ_action +KernelVersion: 4.16 +Contact: [email protected] +Description: + Action mode of Count Y for Signal Z. This attribute indicates + the condition of Signal Z that triggers the count function + evaluation for Count Y. Four action modes are available: none, + rising edge, falling edge, and both edges. + + None: + Signal does not trigger the count function. In + Pulse-Direction count function mode, this Signal is + evaluated as Direction. + + Rising Edge: + Low state transitions to High state. + + Falling Edge: + High state transitions to Low state. + + Both Edges: + Any state transition. + +What: /sys/bus/counter/devices/counterX/signalY +KernelVersion: 4.16 +Contact: [email protected] +Description: + Signal data of Signal Y. This is the respective input level + represented by two available states: low and high. -- 2.15.1
