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>
At present banks must be named and it is not possible to refer to GPIOs by
number in driver model. Some boards use numbering - e.g. OMAP. It is fairly
easy to support by detecting the absense of a bank name (which starts with
a letter).
Add support for numbered GPIOs in addition to the existing bank support.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@ti.com>
We want 'N0' and 'n0' to mean the same thing, so ensure that case is not
considered when naming GPIO banks.
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>
Simon Glass
Heiko Schocher