.. kernel-doc:: include/linux/parport.h :internal:
.. kernel-doc:: drivers/parport/ieee1284.c :export:
.. kernel-doc:: drivers/parport/share.c :export:
.. kernel-doc:: drivers/parport/daisy.c :internal:
.. kernel-doc:: drivers/tty/serial/serial_core.c :export:
.. kernel-doc:: drivers/tty/serial/8250/8250_core.c :export:
Pulse-width modulation is a modulation technique primarily used to control power supplied to electrical devices.
The PWM framework provides an abstraction for providers and consumers of PWM signals. A controller that provides one or more PWM signals is registered as :c:type:`struct pwm_chip <pwm_chip>`. Providers are expected to embed this structure in a driver-specific structure. This structure contains fields that describe a particular chip.
A chip exposes one or more PWM signal sources, each of which exposed as a :c:type:`struct pwm_device <pwm_device>`. Operations can be performed on PWM devices to control the period, duty cycle, polarity and active state of the signal.
Note that PWM devices are exclusive resources: they can always only be used by one consumer at a time.
.. kernel-doc:: include/linux/pwm.h :internal:
.. kernel-doc:: drivers/pwm/core.c :export: