Doug / smarc-fsl-linux-kernel

16 Dec, 2009

1 commit

  • 076974618   gpiolib: add support for changing value polarity in sysfs ... Browse Code »

    Drivers may use gpiolib sysfs as part of their public user space
    interface. The GPIO number and polarity might change from board to
    board. The gpio_export_link() call can be used to hide the GPIO number
    from user space. Add support for also hiding the GPIO line polarity
    changes from user space.

    Signed-off-by: Jani Nikula
    Cc: David Brownell
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jani Nikula
     

23 Sep, 2009

1 commit

  • a4177ee7f   gpiolib: allow exported GPIO nodes to be named using sysfs links ... Browse Code »

    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
    Acked-by: David Brownell
    Cc: Daniel Silverstone
    Signed-off-by: Randy Dunlap
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jani Nikula
     

17 Oct, 2008

1 commit

  • 3d599d1ca   gpio_free might sleep, generic part ... Browse Code »

    According to the documentation gpio_free should only be called from task
    context only. To make this more explicit add a might sleep to all
    implementations.

    This is the generic part which changes gpiolib and the fallback
    implementation only.

    Signed-off-by: Uwe Kleine-König
    Cc: David Brownell
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Uwe Kleine-König
     

26 Jul, 2008

1 commit

  • d8f388d8d   gpio: sysfs interface ... Browse Code »

    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
    Cc: Guennadi Liakhovetski
    Cc: Greg KH
    Cc: Kay Sievers
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Brownell
     

25 May, 2008

1 commit

  • 6ea0205b5   gpio: build fixes ... Browse Code »

    This fixes various gpio-related build errors (mostly potential)
    reported in part by Russell King and Uwe Kleine-König.

    Signed-off-by: David Brownell
    Cc: Uwe Kleine-König
    Cc: Russell King
    Cc: Arnaud Patard
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Brownell
     

05 Mar, 2008

1 commit

  • 7560fa60f   gpio: <linux/gpio.h> and "no GPIO support here" stubs ... Browse Code »

    Add a defining fail/warn stubs for GPIO calls on platforms that
    don't support the GPIO programming interface. That includes the arch-specific
    implementation glue otherwise.

    This facilitates a new model for GPIO usage: drivers that can use GPIOs if
    they're available, but don't require them. One example of such a driver is
    NAND driver for various FreeScale chips. On platforms update with GPIO
    support, they can be used instead of a worst-case delay to verify that the
    BUSY signal is off.

    (Also includes a couple minor unrelated doc updates.)

    Signed-off-by: David Brownell
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    David Brownell