Lines Matching +full:in +full:- +full:line

1 .. SPDX-License-Identifier: GPL-2.0
12 GPIO_V2_GET_LINE_IOCTL - Request a line or lines from the kernel.
34 On success, the requesting process is granted exclusive access to the line
35 value, write access to the line configuration, and may receive events when
36 edges are detected on the line, all of which are described in more detail in
37 :ref:`gpio-v2-line-request`.
39 A number of lines may be requested in the one line request, and request
41 as possible. e.g. gpio-v2-line-get-values-ioctl.rst will read all the
44 The state of a line, including the value of output lines, is guaranteed to
46 file descriptor is closed, the state of the line becomes uncontrolled from
49 Requesting a line already in use is an error (**EBUSY**).
51 Closing the ``chip_fd`` has no effect on existing line requests.
53 .. _gpio-v2-get-line-config-rules:
56 -------------------
58 For any given requested line, the following configuration rules apply:
63 and the line is requested "as-is" to allow reading of the line value
69 If none are set then the line is assumed push-pull.
77 and falling edges.  Requesting edge detection from a line that does not support
88 applies to both the values returned by gpio-v2-line-get-values-ioctl.rst and
89 the edges returned by gpio-v2-line-event-read.rst.  If not
90 supported directly by hardware, debouncing is emulated in software by the
91 kernel.  Requesting debounce on a line that supports neither debounce in
97 .. _gpio-v2-get-line-config-support:
100 ---------------------
105  - reject the request
106  - emulate the feature in software
107  - treat the feature as best effort
110 in software, and the impact on the hardware and userspace if the feature is not
127 Worst case the line floats rather than being biased as expected.
129 Debounce is emulated by applying a filter to hardware interrupts on the line.
130 An edge event is generated after an edge is detected and the line remains
134 Drive is emulated by switching the line to an input when the line should not
140 In all cases, the configuration reported by gpio-v2-get-lineinfo-ioctl.rst
142 Userspace cannot determine if a feature is supported in hardware, is
151 On error -1 and the ``errno`` variable is set appropriately.
152 Common error codes are described in error-codes.rst.