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Merge tag 'gpio-v5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

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Pull GPIO updates from Linus Walleij:
 "This is the bulk of the GPIO changes for the v5.11 kernel cycle:

  Core changes:

   - Retired the old set-up function for GPIO IRQ chips. All chips now
     use the template struct gpio_irq_chip and pass that to the core to
     be set up alongside the gpio_chip. We can finally get rid of the
     old cruft.

   - Some refactoring and clean up of the core code.

   - Support edge event timestamps to be stamped using REALTIME (wall
     clock) timestamps. We have found solid use cases for this, so we
     support it.

  New drivers:

   - MStar MSC313 GPIO driver.

   - HiSilicon GPIO driver.

  Driver improvements:

   - The PCA953x driver now also supports the NXP PCAL9554B/C chips.

   - The mockup driver can now be probed from the device tree which is
     pretty useful for virtual prototyping of devices.

   - The Rcar driver now supports .get_multiple()

   - The MXC driver dropped some legacy and became a pure device tree
     client.

   - The Exar driver was moved over to the IDA interface for
     enumerating, and also switched over to using regmap for register
     access"

* tag 'gpio-v5.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (87 commits)
  MAINTAINERS: Remove reference to non-existing file
  gpio: hisi: Do not require ACPI for COMPILE_TEST
  MAINTAINERS: Add maintainer for HiSilicon GPIO driver
  gpio: gpio-hisi: Add HiSilicon GPIO support
  gpio: cs5535: Simplify the return expression of cs5535_gpio_probe()
  gpiolib: irq hooks: fix recursion in gpiochip_irq_unmask
  dt-bindings: mt7621-gpio: convert bindings to YAML format
  gpiolib: cdev: Flag invalid GPIOs as used
  gpio: put virtual gpio device into their own submenu
  drivers: gpio: amd8111: use SPDX-License-Identifier
  drivers: gpio: amd8111: prefer dev_err()/dev_info() over raw printk
  drivers: gpio: bt8xx: prefer dev_err()/dev_warn() over of raw printk
  gpio: Add TODO item for debugfs interface
  gpio: just plain warning when nonexisting gpio requested
  tools: gpio: add option to report wall-clock time to gpio-event-mon
  tools: gpio: add support for reporting realtime event clock to lsgpio
  gpiolib: cdev: allow edge event timestamps to be configured as REALTIME
  gpio: msc313: MStar MSC313 GPIO driver
  dt-bindings: gpio: Binding for MStar MSC313 GPIO controller
  dt-bindings: gpio: Add a binding header for the MSC313 GPIO driver
  ...
This commit is contained in:
Linus Torvalds
2020-12-17 18:07:20 -08:00
parent 345b17acb1 7ac5548882
commit a409ed156a
46 changed files with 1630 additions and 825 deletions
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18
Documentation/driver-api/gpio/consumer.rst
View File

@@ -440,18 +440,20 @@ For details refer to Documentation/firmware-guide/acpi/gpio-properties.rst
Interacting With the Legacy GPIO Subsystem
==========================================
Many kernel subsystems still handle GPIOs using the legacy integer-based
interface. Although it is strongly encouraged to upgrade them to the safer
descriptor-based API, the following two functions allow you to convert a GPIO
descriptor into the GPIO integer namespace and vice-versa::
Many kernel subsystems and drivers still handle GPIOs using the legacy
integer-based interface. It is strongly recommended to update these to the new
gpiod interface. For cases where both interfaces need to be used, the following
two functions allow to convert a GPIO descriptor into the GPIO integer namespace
and vice-versa::
int desc_to_gpio(const struct gpio_desc *desc)
struct gpio_desc *gpio_to_desc(unsigned gpio)
The GPIO number returned by desc_to_gpio() can be safely used as long as the
GPIO descriptor has not been freed. All the same, a GPIO number passed to
gpio_to_desc() must have been properly acquired, and usage of the returned GPIO
descriptor is only possible after the GPIO number has been released.
The GPIO number returned by desc_to_gpio() can safely be used as a parameter of
the gpio\_*() functions for as long as the GPIO descriptor `desc` is not freed.
All the same, a GPIO number passed to gpio_to_desc() must first be properly
acquired using e.g. gpio_request_one(), and the returned GPIO descriptor is only
considered valid until that GPIO number is released using gpio_free().
Freeing a GPIO obtained by one API with the other API is forbidden and an
unchecked error.

67
Documentation/driver-api/gpio/driver.rst
View File

@@ -416,7 +416,8 @@ The preferred way to set up the helpers is to fill in the
struct gpio_irq_chip inside struct gpio_chip before adding the gpio_chip.
If you do this, the additional irq_chip will be set up by gpiolib at the
same time as setting up the rest of the GPIO functionality. The following
is a typical example of a cascaded interrupt handler using gpio_irq_chip:
is a typical example of a chained cascaded interrupt handler using
the gpio_irq_chip:
.. code-block:: c
@@ -452,7 +453,46 @@ is a typical example of a cascaded interrupt handler using gpio_irq_chip:
return devm_gpiochip_add_data(dev, &g->gc, g);
The helper support using hierarchical interrupt controllers as well.
The helper supports using threaded interrupts as well. Then you just request
the interrupt separately and go with it:
.. code-block:: c
/* Typical state container with dynamic irqchip */
struct my_gpio {
struct gpio_chip gc;
struct irq_chip irq;
};
int irq; /* from platform etc */
struct my_gpio *g;
struct gpio_irq_chip *girq;
/* Set up the irqchip dynamically */
g->irq.name = "my_gpio_irq";
g->irq.irq_ack = my_gpio_ack_irq;
g->irq.irq_mask = my_gpio_mask_irq;
g->irq.irq_unmask = my_gpio_unmask_irq;
g->irq.irq_set_type = my_gpio_set_irq_type;
ret = devm_request_threaded_irq(dev, irq, NULL,
irq_thread_fn, IRQF_ONESHOT, "my-chip", g);
if (ret < 0)
return ret;
/* Get a pointer to the gpio_irq_chip */
girq = &g->gc.irq;
girq->chip = &g->irq;
/* This will let us handle the parent IRQ in the driver */
girq->parent_handler = NULL;
girq->num_parents = 0;
girq->parents = NULL;
girq->default_type = IRQ_TYPE_NONE;
girq->handler = handle_bad_irq;
return devm_gpiochip_add_data(dev, &g->gc, g);
The helper supports using hierarchical interrupt controllers as well.
In this case the typical set-up will look like this:
.. code-block:: c
@@ -493,32 +533,13 @@ the parent hardware irq from a child (i.e. this gpio chip) hardware irq.
As always it is good to look at examples in the kernel tree for advice
on how to find the required pieces.
The old way of adding irqchips to gpiochips after registration is also still
available but we try to move away from this:
- DEPRECATED: gpiochip_irqchip_add(): adds a chained cascaded irqchip to a
gpiochip. It will pass the struct gpio_chip* for the chip to all IRQ
callbacks, so the callbacks need to embed the gpio_chip in its state
container and obtain a pointer to the container using container_of().
(See Documentation/driver-api/driver-model/design-patterns.rst)
- gpiochip_irqchip_add_nested(): adds a nested cascaded irqchip to a gpiochip,
as discussed above regarding different types of cascaded irqchips. The
cascaded irq has to be handled by a threaded interrupt handler.
Apart from that it works exactly like the chained irqchip.
- gpiochip_set_nested_irqchip(): sets up a nested cascaded irq handler for a
gpio_chip from a parent IRQ. As the parent IRQ has usually been
explicitly requested by the driver, this does very little more than
mark all the child IRQs as having the other IRQ as parent.
If there is a need to exclude certain GPIO lines from the IRQ domain handled by
these helpers, we can set .irq.need_valid_mask of the gpiochip before
devm_gpiochip_add_data() or gpiochip_add_data() is called. This allocates an
.irq.valid_mask with as many bits set as there are GPIO lines in the chip, each
bit representing line 0..n-1. Drivers can exclude GPIO lines by clearing bits
from this mask. The mask must be filled in before gpiochip_irqchip_add() or
gpiochip_irqchip_add_nested() is called.
from this mask. The mask can be filled in the init_valid_mask() callback
that is part of the struct gpio_irq_chip.
To use the helpers please keep the following in mind: