Commit Graph

12 Commits

Author SHA1 Message Date
Christophe Leroy 95b39792c6 gpio: aggregator: Stop using ARCH_NR_GPIOS
ARCH_NR_GPIOS is used locally in aggr_parse() as the maximum number
of GPIOs to be aggregated together by the driver since
commit ec75039d55 ("gpio: aggregator: Use bitmap_parselist() for
parsing GPIO offsets").

Don't rely on the total possible number of GPIOs in the system but
define a local arbitrary macro for that, set to 512 which should be
large enough as it is also the default value for ARCH_NR_GPIOS.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2022-10-17 11:02:35 +02:00
Geert Uytterhoeven 2cba05451a gpio: aggregator: Fix calling into sleeping GPIO controllers
If the parent GPIO controller is a sleeping controller (e.g. a GPIO
controller connected to I2C), getting or setting a GPIO triggers a
might_sleep() warning.  This happens because the GPIO Aggregator takes
the can_sleep flag into account only for its internal locking, not for
calling into the parent GPIO controller.

Fix this by using the gpiod_[gs]et*_cansleep() APIs when calling into a
sleeping GPIO controller.

Reported-by: Mikko Salomäki <ms@datarespons.se>
Fixes: 828546e242 ("gpio: Add GPIO Aggregator")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2022-02-02 11:53:46 +01:00
Geert Uytterhoeven a00128dfc8 gpio: aggregator: Add interrupt support
Currently the GPIO Aggregator does not support interrupts.  This means
that kernel drivers going from a GPIO to an IRQ using gpiod_to_irq(),
and userspace applications using line events do not work.

Add interrupt support by providing a gpio_chip.to_irq() callback, which
just calls into the parent GPIO controller.

Note that this does not implement full interrupt controller (irq_chip)
support, so using e.g. gpio-keys with "interrupts" instead of "gpios"
still does not work.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2021-12-03 15:54:31 +01:00
Geert Uytterhoeven aa4858eb82 gpio: aggregator: Wrap access to gpiochip_fwd.tmp[]
The tmp[] member of the gpiochip_fwd structure is used to store both the
temporary values bitmap and the desc pointers for operations on multiple
GPIOs.  As both are arrays with sizes unknown at compile-time, accessing
them requires offset calculations, which are currently duplicated in
gpio_fwd_get_multiple() and gpio_fwd_set_multiple().

Introduce (a) accessors for both arrays and (b) a macro to calculate the
needed storage size.  This confines the layout of the tmp[] member into
a single spot, to ease maintenance.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
2021-10-13 16:19:23 +02:00
Andy Shevchenko ac505b6f5f gpio: aggregator: Replace custom get_arg() with a generic next_arg()
cmdline library provides next_arg() helper to traverse over parameters
and their values given in command line. Replace custom approach in the driver
by it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
2021-05-05 16:07:40 +02:00
Andy Shevchenko 6e004a9829 gpio: aggregator: Remove trailing comma in terminator entries
Remove trailing comma in terminator entries to avoid potential
expanding an array behind it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
2021-02-15 11:43:32 +01:00
Andy Shevchenko b2498cb87c gpio: aggregator: Use compound literal from the header
Instead of doing it in place, convert GPIO_LOOKUP_IDX() and GPIO_HOG()
to be compund literals that's allow to use them as rvalue in assignments.

Due to above conversion, use compound literal from the header
in the gpio-aggregator.c.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
2021-02-15 11:43:32 +01:00
Andy Shevchenko deb631c401 gpio: aggregator: Replace isrange() by using get_options()
We already have a nice helper called get_options() which can be used
to validate the input format. Replace isrange() by using it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
2021-02-15 11:43:31 +01:00
Andy Shevchenko 01e8d85b68 gpio: aggregator: Refactor ->{get, set}_multiple() to make Sparse happy
Sparse can't see locking scheme used in ->get_multiple() and
->set_multiple() callbacks.
  CHECK   .../drivers/gpio/gpio-aggregator.c
  .../spinlock.h:409:9: warning: context imbalance in 'gpio_fwd_get_multiple' - unexpected unlock
  .../spinlock.h:409:9: warning: context imbalance in 'gpio_fwd_set_multiple' - unexpected unlock

Refactor them to have better readability and make Sparse happy.

Code size impact is +52 bytes with arm-linux-gnueabihf-gcc 7.5.0.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-08-18 21:39:39 +02:00
Geert Uytterhoeven ec75039d55 gpio: aggregator: Use bitmap_parselist() for parsing GPIO offsets
Replace the custom code to parse GPIO offsets and/or GPIO offset ranges
by a call to bitmap_parselist(), and an iteration over the returned bit
mask.

This should have no impact on the format of the configuration parameters
written to the "new_device" virtual file in sysfs.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200701114212.8520-3-geert+renesas@glider.be
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2020-07-07 14:30:27 +02:00
Geert Uytterhoeven 2073ea3ab1 gpio: aggregator: Drop pre-initialization in get_arg()
In get_arg(), the variable start is pre-initialized, but overwritten
again in the first statement.  Rework the assignment to not rely on
pre-initialization, to make the code easier to read.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200701114212.8520-2-geert+renesas@glider.be
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2020-07-07 14:30:27 +02:00
Geert Uytterhoeven 828546e242 gpio: Add GPIO Aggregator
GPIO controllers are exported to userspace using /dev/gpiochip*
character devices.  Access control to these devices is provided by
standard UNIX file system permissions, on an all-or-nothing basis:
either a GPIO controller is accessible for a user, or it is not.
Currently no mechanism exists to control access to individual GPIOs.

Hence add a GPIO driver to aggregate existing GPIOs, and expose them as
a new gpiochip.

This supports the following use cases:
  - Aggregating GPIOs using Sysfs
    This is useful for implementing access control, and assigning a set
    of GPIOs to a specific user or virtual machine.
  - Generic GPIO Driver
    This is useful for industrial control, where it can provide
    userspace access to a simple GPIO-operated device described in DT,
    cfr. e.g. spidev for SPI-operated devices.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Link: https://lore.kernel.org/r/20200511145257.22970-5-geert+renesas@glider.be
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2020-05-18 10:12:42 +02:00