kernel/linux.git/Documentation/userspace-api/gpio, branch v6.12.80Linux kernel stable tree (mirror)https://git.radix-linux.su/kernel/linux.git/atom?h=v6.12.802024-07-01T07:38:45+00:00Documentation: gpio: Reconfiguration with unset direction (uAPI v2)2024-07-01T07:38:45+00:00Kent Gibsonwarthog618@gmail.com2024-06-26T05:29:25+00:00urn:sha1:6a9c15083b1662a4b7b36e787272deb696d72c24
Update description of reconfiguration rules, adding requirement that a
direction flag be set to enable changing configuration for a line.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240626052925.174272-5-warthog618@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Documentation: gpio: Reconfiguration with unset direction (uAPI v1)2024-07-01T07:38:45+00:00Kent Gibsonwarthog618@gmail.com2024-06-26T05:29:24+00:00urn:sha1:e48fe75afa539d110753f7420aa398ef89f8e383
Update description of reconfiguration rules, adding requirement that a
direction flag be set or the configuration is considered invalid.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240626052925.174272-4-warthog618@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Documentation: gpio: Clarify effect of active low flag on line edges2024-06-12T12:02:54+00:00Kent Gibsonwarthog618@gmail.com2024-06-10T09:21:57+00:00urn:sha1:08d94c7428680715527757585a6c4575fcf571b9
The documentation does not make sufficiently clear that edge polarity is
based on changes to the logical line values, and that the physical
polarity of edges is dependent on the active low flag.
Clarify the relationship between the active low flag and edge polarity
for the functions that read edge events.
Suggested-by: David C. Rankin <drankinatty@gmail.com>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240610092157.9147-3-warthog618@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Documentation: gpio: Clarify effect of active low flag on line values2024-06-12T12:02:54+00:00Kent Gibsonwarthog618@gmail.com2024-06-10T09:21:56+00:00urn:sha1:5ca84d416e1ca82ca068906fc1386f61a57b17f2
The documentation does not make sufficiently clear that the uAPI deals with
logical line values, nor does it describe the influence of the active low
flag on the mapping between physical and logical line values.
Clarify the relationship between physical and logical line values and the
effect of the active low flag for ioctls passing line values.
Suggested-by: David C. Rankin <drankinatty@gmail.com>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240610092157.9147-2-warthog618@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
docs: gpio: prefer pread(2) for interrupt reading2024-06-10T07:37:52+00:00Huichun Fengfoxhoundsk.tw@gmail.com2024-06-09T17:37:28+00:00urn:sha1:7f1e45f4ae7671550e15354ef87194bccd99ecec
In legacy sysfs GPIO, when using poll(2) on the sysfs GPIO value for
state change awaiting, a subsequent read(2) is required for consuming
the event, which the doc recommends the use of lseek(2) or
close-and-reopen to reset the file offset afterwards.
The recommendations however, require at least 2 syscalls to consume
the event. Gladly, use of pread(2) require only 1 syscall for the
consumption. Let's advertise this usage by prioritizing its placement.
Signed-off-by: Huichun Feng <foxhoundsk.tw@gmail.com>
Link: https://lore.kernel.org/r/20240609173728.2950808-1-foxhoundsk.tw@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Documentation: gpio: fix typo2024-04-02T08:50:28+00:00David Lechnerdlechner@baylibre.com2024-03-29T14:43:16+00:00urn:sha1:a261e208e137f3ae4cd44dffd4aab011457420e7
EOPNOTSUPP has two 'P's.
Signed-off-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Documentation: gpio: clarify sysfs line values are logical2024-02-14T09:28:48+00:00Kent Gibsonwarthog618@gmail.com2024-02-12T09:34:20+00:00urn:sha1:9e69d6d84e3841df073601440774a2221781fc1e
Clarify that line values are logical, not physical, by replacing high/low
terminology with active/inactive.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Reviewed-by: Andy Shevchenko <amdy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Documentation: gpio: describe uAPI behaviour for unsupported config2024-01-25T08:42:25+00:00Kent Gibsonwarthog618@gmail.com2024-01-23T13:38:28+00:00urn:sha1:42969726a19f796f0e731ec74347fd8a0e4e91a2
The existing uAPI documentation does not adequately describe how the kernel
handles the case where the underlying hardware or driver does not support
the requested configuration.
Add a Configuration Support section describing that behaviour to both the
v1 and v2 documentation, and better document the errors returned where the
requested configuration cannot be supported.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Documentation: gpio: add chardev v1 userspace API documentation2024-01-22T09:49:07+00:00Kent Gibsonwarthog618@gmail.com2024-01-15T00:48:44+00:00urn:sha1:16b2bb7fe5e4a0757608e844902fdf05617f51f8
Add documentation for v1 of the GPIO character device userspace API
to the obsolete section of both the admin-guide and userspace-api
books.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Documentation: gpio: update sysfs documentation to reference new chardev doc2024-01-22T09:49:07+00:00Kent Gibsonwarthog618@gmail.com2024-01-15T00:48:43+00:00urn:sha1:e10b641753837e267462b64f8cb395ab1e625027
Update GPIO sysfs interface documentation to reference the new
chardev document rather than gpio.h.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>