diff options
| author | Jani Nikula <ext-jani.1.nikula@nokia.com> | 2009-09-23 03:46:33 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-23 18:39:46 +0400 |
| commit | a4177ee7f1a83eecb1d75e85d32664b023ef65e9 (patch) | |
| tree | 614b12b1f28a1a9090d96bea33639265e3e79839 /drivers/gpio | |
| parent | d8c1acb1664d17dd995e34507533321e986d9215 (diff) | |
| download | linux-a4177ee7f1a83eecb1d75e85d32664b023ef65e9.tar.xz | |
gpiolib: allow exported GPIO nodes to be named using sysfs links
Commit 926b663ce8215ba448960e1ff6e58b67a2c3b99b (gpiolib: allow GPIOs to
be named) already provides naming on the chip level. This patch provides
more flexibility by allowing multiple names where ever in sysfs on a per
GPIO basis.
Adapted from David Brownell's comments on a similar concept:
http://lkml.org/lkml/2009/4/20/203.
[randy.dunlap@oracle.com: fix build for CONFIG_GENERIC_GPIO=n]
Signed-off-by: Jani Nikula <ext-jani.1.nikula@nokia.com>
Acked-by: David Brownell <david-b@pacbell.net>
Cc: Daniel Silverstone <dsilvers@simtec.co.uk>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/gpio')
| -rw-r--r-- | drivers/gpio/gpiolib.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 51a8d4103be5..aef6b3d8e2cf 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -505,6 +505,51 @@ static int match_export(struct device *dev, void *data) } /** + * gpio_export_link - create a sysfs link to an exported GPIO node + * @dev: device under which to create symlink + * @name: name of the symlink + * @gpio: gpio to create symlink to, already exported + * + * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN + * node. Caller is responsible for unlinking. + * + * Returns zero on success, else an error. + */ +int gpio_export_link(struct device *dev, const char *name, unsigned gpio) +{ + struct gpio_desc *desc; + int status = -EINVAL; + + if (!gpio_is_valid(gpio)) + goto done; + + mutex_lock(&sysfs_lock); + + desc = &gpio_desc[gpio]; + + if (test_bit(FLAG_EXPORT, &desc->flags)) { + struct device *tdev; + + tdev = class_find_device(&gpio_class, NULL, desc, match_export); + if (tdev != NULL) { + status = sysfs_create_link(&dev->kobj, &tdev->kobj, + name); + } else { + status = -ENODEV; + } + } + + mutex_unlock(&sysfs_lock); + +done: + if (status) + pr_debug("%s: gpio%d status %d\n", __func__, gpio, status); + + return status; +} +EXPORT_SYMBOL_GPL(gpio_export_link); + +/** * gpio_unexport - reverse effect of gpio_export() * @gpio: gpio to make unavailable * |