Updated and proofread the documentation for GPIO drivers a bit
when looking over the changes for generic configuration.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Currently we already have two pin configuration related callbacks
available for GPIO chips .set_single_ended() and .set_debounce(). In
future we expect to have even more, which does not scale well if we need
to add yet another callback to the GPIO chip structure for each possible
configuration parameter.
Better solution is to reuse what we already have available in the
generic pinconf.
To support this, we introduce a new .set_config() callback for GPIO
chips. The callback takes a single packed pin configuration value as
parameter. This can then be extended easily beyond what is currently
supported by just adding new types to the generic pinconf enum.
If the GPIO driver is backed up by a pinctrl driver the GPIO driver can
just assign gpiochip_generic_config() (introduced in this patch) to
.set_config and that will take care configuration requests are directed
to the pinctrl driver.
We then convert the existing drivers over .set_config() and finally
remove the .set_single_ended() and .set_debounce() callbacks.
Suggested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This tries to simplify the use of CONFIG_GPIOLIB_IRQCHIP when
using threaded interrupts: add a new call
gpiochip_irqchip_add_nested() to indicate that we're dealing
with a nested rather than a chained irqchip, then create a
separate gpiochip_set_nested_irqchip() to mirror
the gpiochip_set_chained_irqchip() call to connect the
parent and child interrupts.
In the nested case gpiochip_set_nested_irqchip() does nothing
more than call irq_set_parent() on each valid child interrupt,
which has little semantic effect in the kernel, but this is
probably still formally correct.
Update all drivers using nested interrupts to use
gpiochip_irqchip_add_nested() so we can now see clearly
which these users are.
The DLN2 driver can drop its specific hack with
.irq_not_threaded as we now recognize whether a chip is
threaded or not from its use of gpiochip_irqchip_add_nested()
signature rather than from inspecting .can_sleep.
We rename the .irq_parent to .irq_chained_parent since this
parent IRQ is only really kept around for the chained
interrupt handlers.
Cc: Lars Poeschel <poeschel@lemonage.de>
Cc: Octavian Purdila <octavian.purdila@intel.com>
Cc: Daniel Baluta <daniel.baluta@intel.com>
Cc: Bin Gao <bin.gao@linux.intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Ajay Thomas <ajay.thomas.david.rajamanickam@intel.com>
Cc: Semen Protsenko <semen.protsenko@globallogic.com>
Cc: Alexander Stein <alexander.stein@systec-electronic.com>
Cc: Phil Reid <preid@electromag.com.au>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
When using GPIO irqchip helpers to setup irqchip for a gpiolib based
driver, it is not possible to select which GPIOs to add to the IRQ domain.
Instead it just adds all GPIOs which is not always desired. For example
there might be GPIOs that for some reason cannot generated normal
interrupts at all.
To support this we add a flag irq_need_valid_mask to struct gpio_chip. When
this flag is set the core allocates irq_valid_mask that holds one bit for
each GPIO the chip has. By default all bits are set but drivers can
manipulate this using set_bit() and clear_bit() accordingly.
Then when gpiochip_irqchip_add() is called, this mask is checked and all
GPIOs with bit is set are added to the IRQ domain created for the GPIO
chip.
Suggested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Make the text clearer, remove reference to confusing "positive"
and "negative" and elaborate a bit.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This has been a totally undocumented feature for years so add some
generic concepts and documentation about open drain/source, include
some facts on how we now support for hardware.
Cc: Michael Hennerich <michael.hennerich@analog.com>
Cc: Nicolas Saenz Julienne <nicolassaenzj@gmail.com>
Cc: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This patch fix some spelling typos found in Documentation/gpio.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Add some information about real time compliance to the driver document.
Inspired by Grygorii Strashko's real time compliance patches.
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This function actually operates on a gpio_chip, so its prefix should
reflect that fact for consistency with other functions defined in
gpio/driver.h.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
To unify how we connect cascaded IRQ chips to parent IRQs, if
NULL us passed as handler to the gpiochip_set_chained_irqchip()
function, assume the chips is nested rather than chained, and
we still get the parent set up correctly by way of this function
call.
Alter the drivers for tc3589x and stmpe to use this to set up
their chained handlers as a demonstration of the usage.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
The current prototype of gpiochip_request_own_desc() requires to obtain
a pointer to a descriptor. This is in contradiction to all other GPIO
request schemes, and imposes an extra step of obtaining a descriptor to
drivers. Most drivers actually cannot even perform that step since the
function that does it (gpichip_get_desc()) is gpiolib-private.
Change gpiochip_request_own_desc() to return a descriptor from a
(chip, hwnum) tuple and update users of this function (currently
gpiolib-acpi only).
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Both functions were introduced to let gpio drivers request their own
gpio pins. Without exporting the functions, this can however only be
used by gpio drivers built into the kernel.
Secondary impact is that the functions can not currently be used by
platform initialization code associated with the gpio-pca953x driver.
This code permits auto-export of gpio pins through platform data, but
if this functionality is used, the module can no longer be unloaded due
to the problem solved with the introduction of gpiochip_request_own_desc
and gpiochip_free_own_desc.
Export both function so they can be used from modules and from
platform initialization code.
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
gpio_lock/unlock_as_irq() are working with (chip, offset) arguments and
are thus not using the old integer namespace. Therefore, there is no
reason to have gpiod variants of these functions working with
descriptors, especially since the (chip, offset) tuple is more suitable
to the users of these functions (GPIO drivers, whereas GPIO descriptors
are targeted at GPIO consumers).
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This adds some documentation about the GPIO irqchips, what types
exist etc.
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Write a few words on how GPIO drivers supplying an irqchip should
be written.
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
gpiolib now exports a new descriptor-based interface which deprecates
the older integer-based one. This patch documents this new interface and
also takes the opportunity to brush-up the GPIO documentation a little
bit.
The new descriptor-based interface follows the same consumer/driver
model as many other kernel subsystems (e.g. clock, regulator), so its
documentation has similarly been splitted into different files.
The content of the former documentation has been reused whenever it
made sense; however, some of its content did not apply to the new
interface anymore and have this been removed. Likewise, new sections
like the mapping of GPIOs to devices have been written from scratch.
The deprecated legacy-based documentation is still available, untouched,
under Documentation/gpio/gpio-legacy.txt.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Linus Walleij
Mika Westerberg
Masanari Iida
Grygorii Strashko
Alexandre Courbot
Guenter Roeck