Certain GPIO devices have the capability to switch their GPIOs into
open-drain mode, that is, instead of actively driving the output
(Push-pull output), the pin is connected to the collector (for a NPN
transistor) or the drain (for a MOSFET) of a transistor, respectively.
The pin then either forms an open circuit or a connection to ground,
depending on the state of the transistor.
This patch adds functions to the GPIO uclass to switch GPIOs to
open-drain mode on devices that support it.
Signed-off-by: Mario Six <mario.six@gdsys.cc>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: York Sun <york.sun@nxp.com>
Many drivers use a common form of offset + flags for device
tree nodes. e.g.:
<&gpio1 2 GPIO_ACTIVE_LOW>
This patch adds a common implementation of this type of parsing
and calls it when a gpio driver doesn't supply its' own xlate
routine.
This will allow removal of the driver-specific versions in a
handful of drivers and simplify the addition of new drivers.
Signed-off-by: Eric Nelson <eric@nelint.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
Some functions do not change the struct gpio_desc parameter. Update these to
use const so this is clear.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
We can use GPIOs as binary digits for reading 'strapping' values. Each GPIO
is assigned a single bit and can be set high or low on the circuit board. We
already have a legacy function for reading these values. Add one that
supports driver model.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
This function can be used for testing to manually request a GPIO for use,
without resorting to the legacy GPIO API.
Signed-off-by: Simon Glass <sjg@chromium.org>
gpio_get_values_as_int() should return an error if something goes wrong.
Also provide gpio_claim_vector(), a function to request the GPIOs and set
them to input mode. Otherwise callers have to do this themselves.
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
Add a deprecation notice to each function so that it is more obvious that we
are moving GPIOs to driver model.
Signed-off-by: Simon Glass <sjg@chromium.org>
At present U-Boot sort-of supports the standard way of reading GPIOs from
device tree nodes, but the support is incomplete, a bit clunky and only
works for GPIO bindings where #gpio-cells is 2.
Add new functions to request GPIOs, taking full account of the device
tree binding. These permit requesting a GPIO with a simple call like:
gpio_request_by_name(dev, "cd-gpios", 0, &desc, GPIOD_IS_IN);
This will request the GPIO, looking at the device's node which might be
this, for example:
cd-gpios = <&gpio TEGRA_GPIO(B, 3) GPIO_ACTIVE_LOW>;
The GPIO will be set to input mode in this case and polarity will be
honoured by the GPIO calls.
It is also possible to request and free a list of GPIOs.
Signed-off-by: Simon Glass <sjg@chromium.org>
Only the GPIO driver knows about the full GPIO device tree binding used by
a device. Add a method to allow the driver to provide this information to the
uclass, including the GPIO offset within the device and flags such as the
polarity.
Signed-off-by: Simon Glass <sjg@chromium.org>
So far driver model's GPIO uclass just implements the existing GPIO API.
This has some limitations:
- it requires manual device tree munging to support GPIOs in device tree
(fdtdec_get_gpio() and friends)
- it does not understand polarity
- it is somewhat slower since we must scan for the GPIO device each time
- Global GPIO numbering can change if other GPIO drivers are probed
- it requires extra steps to set the GPIO direction and value
The new functions have a dm_ prefix where necessary to avoid name conflicts
but we can remove that when it is no-longer needed. The new struct gpio_desc
holds all required information about the GPIO. For now this is intended to
be stored by the client requesting the GPIO, but in future it might be
brought into the uclass in some way.
With these changes the old GPIO API still works, and uses the driver model
API underneath.
Signed-off-by: Simon Glass <sjg@chromium.org>
For board IDs a common approach is to set aside several GPIOs for use in
determining the board ID. This can provide information about board features
and the revision.
Add a function that turns a list of GPIOs into an integer by assigning
each GPIO to a single bit.
Signed-off-by: Simon Glass <sjg@chromium.org>
We have several GPIO drivers now and all are doing similar things to record
which GPIOs are reserved.
Move this logic into the uclass to make the drivers similar.
We retain the request()/free() methods since currently one driver does use
these for setting up the pin.
Signed-off-by: Simon Glass <sjg@chromium.org>
The GPIO list is very long in many cases and most of them are not used.
By default, show only the GPIOs that are in use, and provide a flag to show
all of them. This makes the 'gpio status' command much more pleasant.
In order to do this, driver model now exposes a method for obtaining the
'function' of a GPIO, which describes whether it is an input or output, for
example. Implementation of this method is optional.
Signed-off-by: Simon Glass <sjg@chromium.org>
using UBI and DM together leads in compiler error, as
both define a "struct device", so rename "struct device"
in include/dm/device.h to "struct udevice", as we use
linux code (MTD/UBI/UBIFS some USB code,...) and cannot
change the linux "struct device"
Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Marek Vasut <marex@denx.de>
Add driver model support for GPIOs. Since existing GPIO drivers do not use
driver model, this feature must be enabled by CONFIG_DM_GPIO. After all
GPO drivers are converted over we can perhaps remove this config.
Tests are provided for the sandbox implementation, and are a sufficient
sanity check for basic operation.
The GPIO uclass understands the concept of named banks of GPIOs, with each
GPIO device providing a single bank. Within each bank the GPIOs are numbered
using an offset from 0 to n-1. For example a bank named 'b' with 20
offsets will provide GPIOs named b0 to b19.
Anonymous GPIO banks are also supported, and are just numbered without any
prefix.
Each time a GPIO driver is added to the uclass, the GPIOs are renumbered
accordinging, so there is always a global GPIO numbering order.
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Pavel Herrmann <morpheus.ibis@gmail.com>
Signed-off-by: Viktor Křivák <viktor.krivak@gmail.com>
Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>
Change "int gp" to "unsigned gpio"
Add request and free entry-points
Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Cc: Joe Hershberger <joe.hershberger@gmail.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Since we want want to have a standard GPIO interface, this adds a definition
for this into include/asm-generic/gpio.h.
Signed-off-by: Simon Glass <sjg@chromium.org>
