summaryrefslogtreecommitdiffstats
path: root/Documentation/ABI
diff options
context:
space:
mode:
authorH Hartley Sweeten <hartleys@visionengravers.com>2013-06-11 10:38:59 -0700
committerThierry Reding <thierry.reding@gmail.com>2013-06-21 11:32:51 +0200
commit76abbdde2d95a3807d0dc6bf9f84d03d0dbd4f3d (patch)
tree63a5476d6fbf80ec90b813461ec7ec67ff462684 /Documentation/ABI
parent3dd0a909479c1d372341d749b4ff94cd638b57da (diff)
downloadlinux-76abbdde2d95a3807d0dc6bf9f84d03d0dbd4f3d.tar.bz2
pwm: Add sysfs interface
Add a simple sysfs interface to the generic PWM framework. /sys/class/pwm/ `-- pwmchipN/ for each PWM chip |-- export (w/o) ask the kernel to export a PWM channel |-- npwm (r/o) number of PWM channels in this PWM chip |-- pwmX/ for each exported PWM channel | |-- duty_cycle (r/w) duty cycle (in nanoseconds) | |-- enable (r/w) enable/disable PWM | |-- period (r/w) period (in nanoseconds) | `-- polarity (r/w) polarity of PWM (normal/inversed) `-- unexport (w/o) return a PWM channel to the kernel Based on work by Lars Poeschel. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Lars Poeschel <poeschel@lemonage.de> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Rob Landley <rob@landley.net> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/sysfs-class-pwm79
1 files changed, 79 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-pwm b/Documentation/ABI/testing/sysfs-class-pwm
new file mode 100644
index 000000000000..c479d77b67c5
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-pwm
@@ -0,0 +1,79 @@
+What: /sys/class/pwm/
+Date: May 2013
+KernelVersion: 3.11
+Contact: H Hartley Sweeten <hsweeten@visionengravers.com>
+Description:
+ The pwm/ class sub-directory belongs to the Generic PWM
+ Framework and provides a sysfs interface for using PWM
+ channels.
+
+What: /sys/class/pwm/pwmchipN/
+Date: May 2013
+KernelVersion: 3.11
+Contact: H Hartley Sweeten <hsweeten@visionengravers.com>
+Description:
+ A /sys/class/pwm/pwmchipN directory is created for each
+ probed PWM controller/chip where N is the base of the
+ PWM chip.
+
+What: /sys/class/pwm/pwmchipN/npwm
+Date: May 2013
+KernelVersion: 3.11
+Contact: H Hartley Sweeten <hsweeten@visionengravers.com>
+Description:
+ The number of PWM channels supported by the PWM chip.
+
+What: /sys/class/pwm/pwmchipN/export
+Date: May 2013
+KernelVersion: 3.11
+Contact: H Hartley Sweeten <hsweeten@visionengravers.com>
+Description:
+ Exports a PWM channel from the PWM chip for sysfs control.
+ Value is between 0 and /sys/class/pwm/pwmchipN/npwm - 1.
+
+What: /sys/class/pwm/pwmchipN/unexport
+Date: May 2013
+KernelVersion: 3.11
+Contact: H Hartley Sweeten <hsweeten@visionengravers.com>
+Description:
+ Unexports a PWM channel.
+
+What: /sys/class/pwm/pwmchipN/pwmX
+Date: May 2013
+KernelVersion: 3.11
+Contact: H Hartley Sweeten <hsweeten@visionengravers.com>
+Description:
+ A /sys/class/pwm/pwmchipN/pwmX directory is created for
+ each exported PWM channel where X is the exported PWM
+ channel number.
+
+What: /sys/class/pwm/pwmchipN/pwmX/period
+Date: May 2013
+KernelVersion: 3.11
+Contact: H Hartley Sweeten <hsweeten@visionengravers.com>
+Description:
+ Sets the PWM signal period in nanoseconds.
+
+What: /sys/class/pwm/pwmchipN/pwmX/duty_cycle
+Date: May 2013
+KernelVersion: 3.11
+Contact: H Hartley Sweeten <hsweeten@visionengravers.com>
+Description:
+ Sets the PWM signal duty cycle in nanoseconds.
+
+What: /sys/class/pwm/pwmchipN/pwmX/polarity
+Date: May 2013
+KernelVersion: 3.11
+Contact: H Hartley Sweeten <hsweeten@visionengravers.com>
+Description:
+ Sets the output polarity of the PWM signal to "normal" or
+ "inversed".
+
+What: /sys/class/pwm/pwmchipN/pwmX/enable
+Date: May 2013
+KernelVersion: 3.11
+Contact: H Hartley Sweeten <hsweeten@visionengravers.com>
+Description:
+ Enable/disable the PWM signal.
+ 0 is disabled
+ 1 is enabled