License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 22:07:57 +08:00
|
|
|
/* SPDX-License-Identifier: GPL-2.0 */
|
2007-02-12 16:53:11 +08:00
|
|
|
#ifndef _ASM_GENERIC_GPIO_H
|
|
|
|
#define _ASM_GENERIC_GPIO_H
|
|
|
|
|
2008-05-24 04:04:58 +08:00
|
|
|
#include <linux/types.h>
|
2008-07-29 06:46:38 +08:00
|
|
|
#include <linux/errno.h>
|
2008-05-24 04:04:58 +08:00
|
|
|
|
2008-07-25 16:46:11 +08:00
|
|
|
#ifdef CONFIG_GPIOLIB
|
2008-02-05 14:28:20 +08:00
|
|
|
|
2008-05-24 04:04:58 +08:00
|
|
|
#include <linux/compiler.h>
|
2013-10-18 01:21:36 +08:00
|
|
|
#include <linux/gpio/driver.h>
|
|
|
|
#include <linux/gpio/consumer.h>
|
2008-05-24 04:04:58 +08:00
|
|
|
|
2008-02-05 14:28:20 +08:00
|
|
|
/* Platforms may implement their GPIO interface with library code,
|
|
|
|
* at a small performance cost for non-inlined operations and some
|
|
|
|
* extra memory (for code and for per-GPIO table entries).
|
|
|
|
*
|
|
|
|
* While the GPIO programming interface defines valid GPIO numbers
|
|
|
|
* to be in the range 0..MAX_INT, this library restricts them to the
|
2008-07-27 06:22:26 +08:00
|
|
|
* smaller range 0..ARCH_NR_GPIOS-1.
|
2010-09-10 07:38:03 +08:00
|
|
|
*
|
|
|
|
* ARCH_NR_GPIOS is somewhat arbitrary; it usually reflects the sum of
|
|
|
|
* builtin/SoC GPIOs plus a number of GPIOs on expanders; the latter is
|
|
|
|
* actually an estimate of a board-specific value.
|
2008-02-05 14:28:20 +08:00
|
|
|
*/
|
|
|
|
|
|
|
|
#ifndef ARCH_NR_GPIOS
|
2016-02-16 23:40:38 +08:00
|
|
|
#if defined(CONFIG_ARCH_NR_GPIO) && CONFIG_ARCH_NR_GPIO > 0
|
|
|
|
#define ARCH_NR_GPIOS CONFIG_ARCH_NR_GPIO
|
|
|
|
#else
|
2014-09-15 22:09:44 +08:00
|
|
|
#define ARCH_NR_GPIOS 512
|
2008-02-05 14:28:20 +08:00
|
|
|
#endif
|
2016-02-16 23:40:38 +08:00
|
|
|
#endif
|
2008-02-05 14:28:20 +08:00
|
|
|
|
2010-09-10 07:38:03 +08:00
|
|
|
/*
|
|
|
|
* "valid" GPIO numbers are nonnegative and may be passed to
|
|
|
|
* setup routines like gpio_request(). only some valid numbers
|
|
|
|
* can successfully be requested and used.
|
|
|
|
*
|
|
|
|
* Invalid GPIO numbers are useful for indicating no-such-GPIO in
|
|
|
|
* platform data and other tables.
|
|
|
|
*/
|
|
|
|
|
2011-05-11 07:23:07 +08:00
|
|
|
static inline bool gpio_is_valid(int number)
|
2008-04-28 17:14:46 +08:00
|
|
|
{
|
2011-05-11 07:23:07 +08:00
|
|
|
return number >= 0 && number < ARCH_NR_GPIOS;
|
2008-04-28 17:14:46 +08:00
|
|
|
}
|
|
|
|
|
2009-12-09 19:53:39 +08:00
|
|
|
struct device;
|
2011-10-24 21:24:10 +08:00
|
|
|
struct gpio;
|
2008-02-05 14:28:20 +08:00
|
|
|
struct seq_file;
|
2008-04-28 17:14:44 +08:00
|
|
|
struct module;
|
2010-06-08 21:48:16 +08:00
|
|
|
struct device_node;
|
2013-02-03 00:29:30 +08:00
|
|
|
struct gpio_desc;
|
2008-02-05 14:28:20 +08:00
|
|
|
|
2013-10-18 01:21:36 +08:00
|
|
|
/* caller holds gpio_lock *OR* gpio is marked as requested */
|
|
|
|
static inline struct gpio_chip *gpio_to_chip(unsigned gpio)
|
|
|
|
{
|
|
|
|
return gpiod_to_chip(gpio_to_desc(gpio));
|
|
|
|
}
|
2008-02-05 14:28:20 +08:00
|
|
|
|
|
|
|
/* Always use the library code for GPIO management calls,
|
|
|
|
* or when sleeping may be involved.
|
|
|
|
*/
|
2011-01-14 09:26:46 +08:00
|
|
|
extern int gpio_request(unsigned gpio, const char *label);
|
2008-02-05 14:28:20 +08:00
|
|
|
extern void gpio_free(unsigned gpio);
|
|
|
|
|
2014-07-24 13:51:02 +08:00
|
|
|
static inline int gpio_direction_input(unsigned gpio)
|
|
|
|
{
|
|
|
|
return gpiod_direction_input(gpio_to_desc(gpio));
|
|
|
|
}
|
|
|
|
static inline int gpio_direction_output(unsigned gpio, int value)
|
|
|
|
{
|
|
|
|
return gpiod_direction_output_raw(gpio_to_desc(gpio), value);
|
|
|
|
}
|
2008-02-05 14:28:20 +08:00
|
|
|
|
2014-07-24 13:51:02 +08:00
|
|
|
static inline int gpio_set_debounce(unsigned gpio, unsigned debounce)
|
|
|
|
{
|
|
|
|
return gpiod_set_debounce(gpio_to_desc(gpio), debounce);
|
|
|
|
}
|
2010-05-27 05:42:23 +08:00
|
|
|
|
2013-10-18 01:21:36 +08:00
|
|
|
static inline int gpio_get_value_cansleep(unsigned gpio)
|
|
|
|
{
|
|
|
|
return gpiod_get_raw_value_cansleep(gpio_to_desc(gpio));
|
|
|
|
}
|
|
|
|
static inline void gpio_set_value_cansleep(unsigned gpio, int value)
|
|
|
|
{
|
|
|
|
return gpiod_set_raw_value_cansleep(gpio_to_desc(gpio), value);
|
|
|
|
}
|
2008-02-05 14:28:20 +08:00
|
|
|
|
|
|
|
|
|
|
|
/* A platform's <asm/gpio.h> code may want to inline the I/O calls when
|
|
|
|
* the GPIO is constant and refers to some always-present controller,
|
|
|
|
* giving direct access to chip registers and tight bitbanging loops.
|
|
|
|
*/
|
2013-10-18 01:21:36 +08:00
|
|
|
static inline int __gpio_get_value(unsigned gpio)
|
|
|
|
{
|
|
|
|
return gpiod_get_raw_value(gpio_to_desc(gpio));
|
|
|
|
}
|
|
|
|
static inline void __gpio_set_value(unsigned gpio, int value)
|
|
|
|
{
|
|
|
|
return gpiod_set_raw_value(gpio_to_desc(gpio), value);
|
|
|
|
}
|
2008-02-05 14:28:20 +08:00
|
|
|
|
2013-10-18 01:21:36 +08:00
|
|
|
static inline int __gpio_cansleep(unsigned gpio)
|
|
|
|
{
|
|
|
|
return gpiod_cansleep(gpio_to_desc(gpio));
|
|
|
|
}
|
2008-02-05 14:28:20 +08:00
|
|
|
|
2013-10-18 01:21:36 +08:00
|
|
|
static inline int __gpio_to_irq(unsigned gpio)
|
|
|
|
{
|
|
|
|
return gpiod_to_irq(gpio_to_desc(gpio));
|
|
|
|
}
|
2008-02-05 14:28:20 +08:00
|
|
|
|
2011-01-14 09:26:46 +08:00
|
|
|
extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *label);
|
2011-05-26 07:20:31 +08:00
|
|
|
extern int gpio_request_array(const struct gpio *array, size_t num);
|
|
|
|
extern void gpio_free_array(const struct gpio *array, size_t num);
|
2010-03-06 05:44:35 +08:00
|
|
|
|
gpio: sysfs interface
This adds a simple sysfs interface for GPIOs.
/sys/class/gpio
/export ... asks the kernel to export a GPIO to userspace
/unexport ... to return a GPIO to the kernel
/gpioN ... for each exported GPIO #N
/value ... always readable, writes fail for input GPIOs
/direction ... r/w as: in, out (default low); write high, low
/gpiochipN ... for each gpiochip; #N is its first GPIO
/base ... (r/o) same as N
/label ... (r/o) descriptive, not necessarily unique
/ngpio ... (r/o) number of GPIOs; numbered N .. N+(ngpio - 1)
GPIOs claimed by kernel code may be exported by its owner using a new
gpio_export() call, which should be most useful for driver debugging.
Such exports may optionally be done without a "direction" attribute.
Userspace may ask to take over a GPIO by writing to a sysfs control file,
helping to cope with incomplete board support or other "one-off"
requirements that don't merit full kernel support:
echo 23 > /sys/class/gpio/export
... will gpio_request(23, "sysfs") and gpio_export(23);
use /sys/class/gpio/gpio-23/direction to (re)configure it,
when that GPIO can be used as both input and output.
echo 23 > /sys/class/gpio/unexport
... will gpio_free(23), when it was exported as above
The extra D-space footprint is a few hundred bytes, except for the sysfs
resources associated with each exported GPIO. The additional I-space
footprint is about two thirds of the current size of gpiolib (!). Since
no /dev node creation is involved, no "udev" support is needed.
Related changes:
* This adds a device pointer to "struct gpio_chip". When GPIO
providers initialize that, sysfs gpio class devices become children of
that device instead of being "virtual" devices.
* The (few) gpio_chip providers which have such a device node have
been updated.
* Some gpio_chip drivers also needed to update their module "owner"
field ... for which missing kerneldoc was added.
* Some gpio_chips don't support input GPIOs. Those GPIOs are now
flagged appropriately when the chip is registered.
Based on previous patches, and discussion both on and off LKML.
A Documentation/ABI/testing/sysfs-gpio update is ready to submit once this
merges to mainline.
[akpm@linux-foundation.org: a few maintenance build fixes]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 16:46:07 +08:00
|
|
|
/*
|
|
|
|
* A sysfs interface can be exported by individual drivers if they want,
|
|
|
|
* but more typically is configured entirely from userspace.
|
|
|
|
*/
|
2013-10-18 01:21:36 +08:00
|
|
|
static inline int gpio_export(unsigned gpio, bool direction_may_change)
|
|
|
|
{
|
|
|
|
return gpiod_export(gpio_to_desc(gpio), direction_may_change);
|
|
|
|
}
|
gpio: sysfs interface
This adds a simple sysfs interface for GPIOs.
/sys/class/gpio
/export ... asks the kernel to export a GPIO to userspace
/unexport ... to return a GPIO to the kernel
/gpioN ... for each exported GPIO #N
/value ... always readable, writes fail for input GPIOs
/direction ... r/w as: in, out (default low); write high, low
/gpiochipN ... for each gpiochip; #N is its first GPIO
/base ... (r/o) same as N
/label ... (r/o) descriptive, not necessarily unique
/ngpio ... (r/o) number of GPIOs; numbered N .. N+(ngpio - 1)
GPIOs claimed by kernel code may be exported by its owner using a new
gpio_export() call, which should be most useful for driver debugging.
Such exports may optionally be done without a "direction" attribute.
Userspace may ask to take over a GPIO by writing to a sysfs control file,
helping to cope with incomplete board support or other "one-off"
requirements that don't merit full kernel support:
echo 23 > /sys/class/gpio/export
... will gpio_request(23, "sysfs") and gpio_export(23);
use /sys/class/gpio/gpio-23/direction to (re)configure it,
when that GPIO can be used as both input and output.
echo 23 > /sys/class/gpio/unexport
... will gpio_free(23), when it was exported as above
The extra D-space footprint is a few hundred bytes, except for the sysfs
resources associated with each exported GPIO. The additional I-space
footprint is about two thirds of the current size of gpiolib (!). Since
no /dev node creation is involved, no "udev" support is needed.
Related changes:
* This adds a device pointer to "struct gpio_chip". When GPIO
providers initialize that, sysfs gpio class devices become children of
that device instead of being "virtual" devices.
* The (few) gpio_chip providers which have such a device node have
been updated.
* Some gpio_chip drivers also needed to update their module "owner"
field ... for which missing kerneldoc was added.
* Some gpio_chips don't support input GPIOs. Those GPIOs are now
flagged appropriately when the chip is registered.
Based on previous patches, and discussion both on and off LKML.
A Documentation/ABI/testing/sysfs-gpio update is ready to submit once this
merges to mainline.
[akpm@linux-foundation.org: a few maintenance build fixes]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 16:46:07 +08:00
|
|
|
|
2013-10-18 01:21:36 +08:00
|
|
|
static inline int gpio_export_link(struct device *dev, const char *name,
|
|
|
|
unsigned gpio)
|
|
|
|
{
|
|
|
|
return gpiod_export_link(dev, name, gpio_to_desc(gpio));
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void gpio_unexport(unsigned gpio)
|
|
|
|
{
|
|
|
|
gpiod_unexport(gpio_to_desc(gpio));
|
|
|
|
}
|
gpio: sysfs interface
This adds a simple sysfs interface for GPIOs.
/sys/class/gpio
/export ... asks the kernel to export a GPIO to userspace
/unexport ... to return a GPIO to the kernel
/gpioN ... for each exported GPIO #N
/value ... always readable, writes fail for input GPIOs
/direction ... r/w as: in, out (default low); write high, low
/gpiochipN ... for each gpiochip; #N is its first GPIO
/base ... (r/o) same as N
/label ... (r/o) descriptive, not necessarily unique
/ngpio ... (r/o) number of GPIOs; numbered N .. N+(ngpio - 1)
GPIOs claimed by kernel code may be exported by its owner using a new
gpio_export() call, which should be most useful for driver debugging.
Such exports may optionally be done without a "direction" attribute.
Userspace may ask to take over a GPIO by writing to a sysfs control file,
helping to cope with incomplete board support or other "one-off"
requirements that don't merit full kernel support:
echo 23 > /sys/class/gpio/export
... will gpio_request(23, "sysfs") and gpio_export(23);
use /sys/class/gpio/gpio-23/direction to (re)configure it,
when that GPIO can be used as both input and output.
echo 23 > /sys/class/gpio/unexport
... will gpio_free(23), when it was exported as above
The extra D-space footprint is a few hundred bytes, except for the sysfs
resources associated with each exported GPIO. The additional I-space
footprint is about two thirds of the current size of gpiolib (!). Since
no /dev node creation is involved, no "udev" support is needed.
Related changes:
* This adds a device pointer to "struct gpio_chip". When GPIO
providers initialize that, sysfs gpio class devices become children of
that device instead of being "virtual" devices.
* The (few) gpio_chip providers which have such a device node have
been updated.
* Some gpio_chip drivers also needed to update their module "owner"
field ... for which missing kerneldoc was added.
* Some gpio_chips don't support input GPIOs. Those GPIOs are now
flagged appropriately when the chip is registered.
Based on previous patches, and discussion both on and off LKML.
A Documentation/ABI/testing/sysfs-gpio update is ready to submit once this
merges to mainline.
[akpm@linux-foundation.org: a few maintenance build fixes]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 16:46:07 +08:00
|
|
|
|
2010-10-28 06:33:16 +08:00
|
|
|
#else /* !CONFIG_GPIOLIB */
|
2008-02-05 14:28:20 +08:00
|
|
|
|
2020-02-05 21:43:36 +08:00
|
|
|
#include <linux/kernel.h>
|
|
|
|
|
2011-05-11 07:23:07 +08:00
|
|
|
static inline bool gpio_is_valid(int number)
|
2008-04-28 17:14:46 +08:00
|
|
|
{
|
|
|
|
/* only non-negative numbers are valid */
|
|
|
|
return number >= 0;
|
|
|
|
}
|
|
|
|
|
2007-02-12 16:53:11 +08:00
|
|
|
/* platforms that don't directly support access to GPIOs through I2C, SPI,
|
|
|
|
* or other blocking infrastructure can use these wrappers.
|
|
|
|
*/
|
|
|
|
|
|
|
|
static inline int gpio_cansleep(unsigned gpio)
|
|
|
|
{
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int gpio_get_value_cansleep(unsigned gpio)
|
|
|
|
{
|
|
|
|
might_sleep();
|
2011-10-21 09:38:32 +08:00
|
|
|
return __gpio_get_value(gpio);
|
2007-02-12 16:53:11 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
static inline void gpio_set_value_cansleep(unsigned gpio, int value)
|
|
|
|
{
|
|
|
|
might_sleep();
|
2011-10-21 09:38:32 +08:00
|
|
|
__gpio_set_value(gpio, value);
|
2007-02-12 16:53:11 +08:00
|
|
|
}
|
|
|
|
|
2010-10-28 06:33:16 +08:00
|
|
|
#endif /* !CONFIG_GPIOLIB */
|
gpio: sysfs interface
This adds a simple sysfs interface for GPIOs.
/sys/class/gpio
/export ... asks the kernel to export a GPIO to userspace
/unexport ... to return a GPIO to the kernel
/gpioN ... for each exported GPIO #N
/value ... always readable, writes fail for input GPIOs
/direction ... r/w as: in, out (default low); write high, low
/gpiochipN ... for each gpiochip; #N is its first GPIO
/base ... (r/o) same as N
/label ... (r/o) descriptive, not necessarily unique
/ngpio ... (r/o) number of GPIOs; numbered N .. N+(ngpio - 1)
GPIOs claimed by kernel code may be exported by its owner using a new
gpio_export() call, which should be most useful for driver debugging.
Such exports may optionally be done without a "direction" attribute.
Userspace may ask to take over a GPIO by writing to a sysfs control file,
helping to cope with incomplete board support or other "one-off"
requirements that don't merit full kernel support:
echo 23 > /sys/class/gpio/export
... will gpio_request(23, "sysfs") and gpio_export(23);
use /sys/class/gpio/gpio-23/direction to (re)configure it,
when that GPIO can be used as both input and output.
echo 23 > /sys/class/gpio/unexport
... will gpio_free(23), when it was exported as above
The extra D-space footprint is a few hundred bytes, except for the sysfs
resources associated with each exported GPIO. The additional I-space
footprint is about two thirds of the current size of gpiolib (!). Since
no /dev node creation is involved, no "udev" support is needed.
Related changes:
* This adds a device pointer to "struct gpio_chip". When GPIO
providers initialize that, sysfs gpio class devices become children of
that device instead of being "virtual" devices.
* The (few) gpio_chip providers which have such a device node have
been updated.
* Some gpio_chip drivers also needed to update their module "owner"
field ... for which missing kerneldoc was added.
* Some gpio_chips don't support input GPIOs. Those GPIOs are now
flagged appropriately when the chip is registered.
Based on previous patches, and discussion both on and off LKML.
A Documentation/ABI/testing/sysfs-gpio update is ready to submit once this
merges to mainline.
[akpm@linux-foundation.org: a few maintenance build fixes]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 16:46:07 +08:00
|
|
|
|
2007-02-12 16:53:11 +08:00
|
|
|
#endif /* _ASM_GENERIC_GPIO_H */
|