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>
Currently a GPIO lookup table can only refer to a specific GPIO by a
tuple, consisting of a GPIO controller label and a GPIO offset inside
the controller.
However, a GPIO may also carry a line name, defined by DT or ACPI.
If present, the line name is the most use-centric way to refer to a
GPIO. Hence add support for looking up GPIOs by line name.
Note that there is no guarantee that GPIO line names are globally
unique, so this will use the first match found.
Implement this by reusing the existing gpiod_lookup infrastructure.
Rename gpiod_lookup.chip_label to gpiod_lookup.key, to make it clear
that this field can have two meanings, and update the kerneldoc and
GPIO_LOOKUP*() macros.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Link: https://lore.kernel.org/r/20200511145257.22970-4-geert+renesas@glider.be
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
acpi_gpiochip_request_interrupts() will check for ACPI handle of
the GPIO chip parent device and bail out if there is none defined.
Thus, has_acpi_companion() is effectively repeating above and
is not needed in the individual driver.
Assigning ->to_irq() unconditionally doesn't change anything, except
an error code, but this we fix as well by propagating it from
platform_get_irq().
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200512182623.54990-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
gpiochip_set_desc_names() no longer rejects GPIO line name collisions.
Hence GPIO line names are not guaranteed to be globally unique.
In case of multiple GPIO lines with the same name, gpio_name_to_desc()
will return the first match found.
Update the comments for gpio_name_to_desc() and
gpiochip_set_desc_names() to match reality.
Fixes: f881bab038 ("gpio: keep the GPIO line names internal")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200511101828.30046-1-geert+renesas@glider.be
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
intel-gpio for v5.8-1
* MSI support for Intel Merrifield
* Refactor gpio-pch to be up-to-date with recent kernel APIs
* Miscellaneous cleanups here and there
The following is an automated git shortlog grouped by driver:
ich:
- fix a typo
merrifield:
- Better show how GPIO and IRQ bases are derived from hardware
- Switch over to MSI interrupts
pch:
- Use in pch_irq_type() macros provided by IRQ core
- Refactor pch_irq_type() to avoid unnecessary locking
- Get rid of unneeded variable in IRQ handler
- Use BIT() and GENMASK() where it's appropriate
gpio updates for v5.8-rc1 - part1
- correct the IRQ type used in to_irq() in gpio-xgene-sb
- add new item to the TODO list
- support building gpio-pl061 as module
- improve pull-up/down support on GPIO expanders in device-tree
- several improvements in gpio-pca953x
- emit a warning for too long GPIO line names
- add MODULE_DEVICE_TABLE to gpio-tegra186
- add support for new variant to gpio-f7188x
- lsgpio can now display bias flags
Export MODULE_DEVICE_TABLE since the driver can be built as a module.
Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Some of the chips supported by the pca953x driver need the most
significant bit in the address word set to automatically increment the
address pointer on subsequent reads and writes (example: PCA9505). With
this bit unset the same register is read multiple times on a multi-byte
read sequence. Other chips must not have this bit set and autoincrement
always (example: PCA9555).
Up to now this AI bit was interpreted to be part of the address, which
resulted in inconsistent regmap caching when a register was written with
AI set and then read without it. This happened for the PCA9505 in
pca953x_gpio_set_multiple() where pca953x_read_regs() bulk read from the
cache for registers 0x8-0xc and then wrote to registers 0x88-0x8c. (Side
note: reading 5 values from offset 0x8 yiels OP0 5 times because AI must
be set to get OP0-OP4, which is another bug that is resolved here as a
by-product.) The same problem happens when calls to gpio_set_value() and
gpio_set_array_value() were mixed.
With this patch the AI bit is always set for chips that support it. This
works as there are no code locations that make use of the behaviour with
AI unset (for the chips that support it).
Note that the call to pca953x_setup_gpio() had to be done a bit earlier
to make the NBANK macro work.
The history of this bug is a bit complicated. Commit b32cecb46b
("gpio: pca953x: Extract the register address mangling to single
function") changed which chips and functions are affected. Commit
3b00691cc4 ("gpio: pca953x: hack to fix 24 bit gpio expanders") used
some duct tape to make the driver at least appear to work. Commit
4942723276 ("gpio: pca953x: Perform basic regmap conversion")
introduced the caching. Commit b4818afeac ("gpio: pca953x: Add
set_multiple to allow multiple bits to be set in one write.") introduced
the .set_multiple() callback which didn't work for chips that need the
AI bit which was fixed later for some chips in 8958262af3 ("gpio:
pca953x: Repair multi-byte IO address increment on PCA9575"). So I'm
sorry, I don't know which commit I should pick for a Fixes: line.
Tested-by: Marcel Gudert <m.gudert@eckelmann.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
The commit 96d7c7b3e6 ("gpio: gpio-pca953x, Add get_multiple function")
basically did everything wrong from style and code reuse perspective, i.e.
- it didn't utilize existing PCA953x internal helpers
- it didn't utilize bitmap API
- it misses the point that ilog2(), besides that BANK_SFT is useless,
can be used in macros
- it has indentation issues.
Rewrite the function completely.
Cc: Paul Thomas <pthomas8589@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Simplify the printing of kernel messages and make the messages more
accurate by using the most appropriate {dev,chip,gpiod}_*() helpers.
Sample impact:
-gpiochip_setup_dev: registered GPIOs 496 to 511 on device: gpiochip0 (e6050000.gpio)
+gpio gpiochip0: registered GPIOs 496 to 511 on e6050000.gpio
-no flags found for gpios
+gpio-953 (?): no flags found for gpios
-GPIO line 355 (PCIE/SATA switch) hogged as output/low
+gpio-355 (PCIE/SATA switch): hogged as output/low
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200424141432.11400-1-geert+renesas@glider.be
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Some DT authors (including myself) have messed up the length of
gpio-line-names and made it longer than it should be. Add a warning here
so that developers can figure out that they've messed up their DT and
should fix it.
Cc: Alexandru M Stan <amstan@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
