1*4882a593SmuzhiyunParallel Port Devices 2*4882a593Smuzhiyun===================== 3*4882a593Smuzhiyun 4*4882a593Smuzhiyun.. kernel-doc:: include/linux/parport.h 5*4882a593Smuzhiyun :internal: 6*4882a593Smuzhiyun 7*4882a593Smuzhiyun.. kernel-doc:: drivers/parport/ieee1284.c 8*4882a593Smuzhiyun :export: 9*4882a593Smuzhiyun 10*4882a593Smuzhiyun.. kernel-doc:: drivers/parport/share.c 11*4882a593Smuzhiyun :export: 12*4882a593Smuzhiyun 13*4882a593Smuzhiyun.. kernel-doc:: drivers/parport/daisy.c 14*4882a593Smuzhiyun :internal: 15*4882a593Smuzhiyun 16*4882a593Smuzhiyun16x50 UART Driver 17*4882a593Smuzhiyun================= 18*4882a593Smuzhiyun 19*4882a593Smuzhiyun.. kernel-doc:: drivers/tty/serial/serial_core.c 20*4882a593Smuzhiyun :export: 21*4882a593Smuzhiyun 22*4882a593Smuzhiyun.. kernel-doc:: drivers/tty/serial/8250/8250_core.c 23*4882a593Smuzhiyun :export: 24*4882a593Smuzhiyun 25*4882a593SmuzhiyunPulse-Width Modulation (PWM) 26*4882a593Smuzhiyun============================ 27*4882a593Smuzhiyun 28*4882a593SmuzhiyunPulse-width modulation is a modulation technique primarily used to 29*4882a593Smuzhiyuncontrol power supplied to electrical devices. 30*4882a593Smuzhiyun 31*4882a593SmuzhiyunThe PWM framework provides an abstraction for providers and consumers of 32*4882a593SmuzhiyunPWM signals. A controller that provides one or more PWM signals is 33*4882a593Smuzhiyunregistered as :c:type:`struct pwm_chip <pwm_chip>`. Providers 34*4882a593Smuzhiyunare expected to embed this structure in a driver-specific structure. 35*4882a593SmuzhiyunThis structure contains fields that describe a particular chip. 36*4882a593Smuzhiyun 37*4882a593SmuzhiyunA chip exposes one or more PWM signal sources, each of which exposed as 38*4882a593Smuzhiyuna :c:type:`struct pwm_device <pwm_device>`. Operations can be 39*4882a593Smuzhiyunperformed on PWM devices to control the period, duty cycle, polarity and 40*4882a593Smuzhiyunactive state of the signal. 41*4882a593Smuzhiyun 42*4882a593SmuzhiyunNote that PWM devices are exclusive resources: they can always only be 43*4882a593Smuzhiyunused by one consumer at a time. 44*4882a593Smuzhiyun 45*4882a593Smuzhiyun.. kernel-doc:: include/linux/pwm.h 46*4882a593Smuzhiyun :internal: 47*4882a593Smuzhiyun 48*4882a593Smuzhiyun.. kernel-doc:: drivers/pwm/core.c 49*4882a593Smuzhiyun :export: 50