diff options
| author | H Hartley Sweeten <hartleys@visionengravers.com> | 2013-06-11 10:38:59 -0700 |
|---|---|---|
| committer | Winnie Hsu <whsu@nvidia.com> | 2014-09-03 18:03:14 -0700 |
| commit | 8e837f9cce974ed641a43535f1185371d68a592c (patch) | |
| tree | 34972965ad2b284eea568fbc58e2a14380a26d86 /Documentation/ABI | |
| parent | ac954dd4168e97d41d68d79d530144333a8ef132 (diff) | |
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.
Bug 200028381
Change-Id: I0c9c6ad2ca7173e6fc3fbe1d3cd3963cde00539a
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>
Signed-off-by: Bibek Basu <bbasu@nvidia.com>
(cherry picked from commit 76abbdde2d95a3807d0dc6bf9f84d03d0dbd4f3d)
Reviewed-on: http://git-master/r/455068
(cherry picked from commit b1824bc0325f84ea04dab7d6d4f7c887c80b1982)
Reviewed-on: http://git-master/r/488690
GVS: Gerrit_Virtual_Submit
Reviewed-by: Winnie Hsu <whsu@nvidia.com>
Tested-by: Winnie Hsu <whsu@nvidia.com>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-pwm | 79 |
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 |