1 .\" Copyright (c) 2018 Emmanuel Vadot <manu@freebsd.org>
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30 .Nm PWMBUS_CHANNEL_CONFIG ,
31 .Nm PWMBUS_CHANNEL_COUNT ,
32 .Nm PWMBUS_CHANNEL_ENABLE ,
33 .Nm PWMBUS_CHANNEL_GET_CONFIG ,
34 .Nm PWMBUS_CHANNEL_GET_FLAGS ,
35 .Nm PWMBUS_CHANNEL_IS_ENABLED ,
36 .Nm PWMBUS_CHANNEL_SET_FLAGS ,
43 .Fn PWMBUS_CHANNEL_CONFIG "device_t bus" "int channel" "uint64_t period" "uint64_t duty"
45 .Fn PWMBUS_CHANNEL_COUNT "device_t bus" "int channel" "int *nchannel"
47 .Fn PWMBUS_CHANNEL_ENABLE "device_t bus" "int channel" "bool enable"
49 .Fn PWMBUS_CHANNEL_GET_CONFIG "device_t bus" "int channel" "uint64_t *period" "uint64_t *duty"
51 .Fn PWMBUS_CHANNEL_GET_FLAGS "device_t bus" "int channel" "uint32_t *flags"
53 .Fn PWMBUS_CHANNEL_IS_ENABLED "device_t bus" "int channel" "bool *enabled"
55 .Fn PWMBUS_CHANNEL_SET_FLAGS "device_t bus" "int channel" "uint32_t flags"
57 The PWMBUS (Pulse-Width Modulation) interface allows a device driver to
58 register to a global bus so other devices in the kernel can use them in a
65 argument is the duration in nanoseconds of one complete on-off cycle, and the
67 argument is the duration in nanoseconds of the on portion of that cycle.
69 Some PWM hardware is organized as a single controller with multiple channels.
70 Channel numbers count up from zero.
71 When multiple channels are present, they sometimes share a common clock or
73 In such cases, changing the period or duty cycle of any one channel may affect
74 other channels within the hardware which share the same resources.
75 Consult the documentation for the underlying PWM hardware device driver for
76 details on channels that share resources.
78 .Bl -tag -width indent
79 .It Fn PWMBUS_CHANNEL_CONFIG "device_t bus" "int channel" "uint64_t period" "uint64_t duty"
80 Configure the period and duty (in nanoseconds) in the PWM controller on the bus
81 for the specified channel.
82 Returns 0 on success or
84 if the values are not supported by the controller or
86 if the PWMBUS controller is in use and does not support changing the value on
88 .It Fn PWMBUS_CHANNEL_COUNT "device_t bus" "int *nchannel"
89 Get the number of channels supported by the controller.
90 .It Fn PWMBUS_CHANNEL_ENABLE "device_t bus" "int channel" "bool enable"
91 Enable the PWM channel.
92 .It Fn PWMBUS_CHANNEL_GET_CONFIG "device_t bus" "int channel" "uint64_t *period" "uint64_t *duty"
93 Get the current configuration of the period and duty for the specified channel.
94 .It Fn PWMBUS_CHANNEL_GET_FLAGS "device_t bus" "int channel" "uint32_t *flags"
95 Get the current flags for the channel.
96 If the driver or controller
97 does not support this, a default method returns a flags value of zero.
98 .It Fn PWMBUS_CHANNEL_IS_ENABLED "device_t bus" "int channel" "bool *enable"
99 Test whether the PWM channel is enabled.
100 .It Fn PWMBUS_CHANNEL_SET_FLAGS "device_t bus" "int channel" "uint32_t flags"
101 Set the flags of the channel (such as inverted polarity).
102 If the driver or controller does not support this a do-nothing default method
108 interface first appear in
112 interface and manual page was written by
113 .An Emmanuel Vadot Aq Mt manu@FreeBSD.org .