1Parallel Port Devices 2===================== 3 4.. kernel-doc:: include/linux/parport.h 5 :internal: 6 7.. kernel-doc:: drivers/parport/ieee1284.c 8 :export: 9 10.. kernel-doc:: drivers/parport/share.c 11 :export: 12 13.. kernel-doc:: drivers/parport/daisy.c 14 :internal: 15 1616x50 UART Driver 17================= 18 19.. kernel-doc:: drivers/tty/serial/8250/8250_core.c 20 :export: 21 22See serial/driver.rst for related APIs. 23 24Pulse-Width Modulation (PWM) 25============================ 26 27Pulse-width modulation is a modulation technique primarily used to 28control power supplied to electrical devices. 29 30The PWM framework provides an abstraction for providers and consumers of 31PWM signals. A controller that provides one or more PWM signals is 32registered as :c:type:`struct pwm_chip <pwm_chip>`. Providers 33are expected to embed this structure in a driver-specific structure. 34This structure contains fields that describe a particular chip. 35 36A chip exposes one or more PWM signal sources, each of which exposed as 37a :c:type:`struct pwm_device <pwm_device>`. Operations can be 38performed on PWM devices to control the period, duty cycle, polarity and 39active state of the signal. 40 41Note that PWM devices are exclusive resources: they can always only be 42used by one consumer at a time. 43 44.. kernel-doc:: include/linux/pwm.h 45 :internal: 46 47.. kernel-doc:: drivers/pwm/core.c 48 :export: 49