Commit graph

73 commits

Author SHA1 Message Date
Sean Anderson
430e136dc1 dm: gpio: Fix gpio_get_list_count failing with livetree
of_parse_phandle_with_args (called by dev_read_phandle_with_args) does not
support getting the length of a phandle list by using the index -1.
Instead, use dev_count_phandle_with_args which supports exactly this
use-case.

Fixes: 8558217153 ("gpio: Convert to use APIs which support live DT")

Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2021-05-04 07:57:18 -04:00
Simon Glass
34f8fc7c85 gpio: Drop dm_gpio_set_dir()
This function is not used. Drop it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
2021-04-12 17:45:40 -04:00
Simon Glass
8a45b22057 gpio: Add a way to read 3-way strapping pins
Using the internal vs. external pull resistors it is possible to get
27 different combinations from 3 strapping pins. Add an implementation
of this.

This involves updating the sandbox GPIO driver to model external and
(weaker) internal pull resistors. The get_value() method now takes account
of what is driving a pin:

   sandbox: GPIOD_EXT_DRIVEN - in which case GPIO_EXT_HIGH provides the
          value
   outside source - in which case GPIO_EXT_PULL_UP/DOWN indicates the
          external state and we work the final state using those flags and
          the internal GPIOD_PULL_UP/DOWN flags

Of course the outside source does not really exist in sandbox. We are just
modelling it for test purpose.

Signed-off-by: Simon Glass <sjg@chromium.org>
2021-03-03 15:40:47 -05:00
Simon Glass
be04f1ab42 gpio: Define the log category in the uclass
This uses log_debug(), etc. but does not define the category. Fix this.

Signed-off-by: Simon Glass <sjg@chromium.org>
2021-03-03 15:40:11 -05:00
Simon Glass
3d64774716 gpio: Use an 'ops' variable everywhere
Update this driver to use the common method of putting the driver
operations in an 'ops' variable install of calling gpio_get_ops()
repeatedly. Make it const since operations do not change.

Signed-off-by: Simon Glass <sjg@chromium.org>

Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
2021-03-03 15:40:11 -05:00
Simon Glass
ca1e1f57be gpio: Replace direction_input() and direction_output()
The new update_flags() method is more flexible since it allows the
driver to see the full flags all at once. Use that in preference to these
two functions. Add comments to that effect.

Signed-off-by: Simon Glass <sjg@chromium.org>

Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
2021-03-03 15:40:11 -05:00
Simon Glass
7e0a96d559 dm: gpio: Add a way to update flags
It is convenient to be able to adjust some of the flags for a GPIO while
leaving others alone. Add a function for this.

Update dm_gpio_set_dir_flags() to make use of this.

Also update dm_gpio_set_value() to use this also, since this allows the
open-drain / open-source features to be implemented directly in the
driver, rather than using the uclass workaround.

Update the sandbox tests accordingly. This involves a lot of changes to
dm_test_gpio_opendrain_opensource() since we no-longer have the direciion
being reported differently depending on the open drain/open source flags.

Also update the STM32 drivers to let the uclass handle the active low/high
logic.

Drop the GPIOD_FLAGS_OUTPUT() macro which is no-longer used.

Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Kory Maincent <kory.maincent@bootlin.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Tested-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Tested-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
2021-03-03 15:40:10 -05:00
Simon Glass
c0c1e62c6e gpio: Rename dm_gpio_get_dir_flags() to dm_gpio_get_flags()
This function can be used to get any flags, not just direction flags.
Rename it to avoid confusion.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
2021-03-03 14:51:06 -05:00
Simon Glass
9648789e26 dm: gpio: Rename get_dir_flags() method to get_flags()
It is more useful to be able to read all the flags, not just the direction
ones. In fact this is what the STM32 driver does. Update the method name
to reflect this.

Tweak the docs a little and use 'flagsp' as the return argument, as is
common in driver model, to indicate it returns a value.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>

Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
2021-03-03 14:51:06 -05:00
Simon Glass
13979fc446 dm: gpio: Rename set_dir_flags() method to update_flags()
The current method is a misnomer since it is also used (e.g. by stm32) to
update pull settings and open source/open drain.

Rename it and expand the documentation to cover a few more details.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>

Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
2021-03-03 14:51:06 -05:00
Simon Glass
4fe406729c gpio: Disable functions not used with of-platdata
These functions use devicetree and cannot work with of-platdata, which has
no runtime devicetree.

If they are used, the current linker error is confusing, since it talks
about missing functions in the bowels of driver model.

Avoid compiling these functions at all with of-platdata, so that a
straightforward link error points to the problem.

Series-changes; 3
- Fix 'wprl' typo

Signed-off-by: Simon Glass <sjg@chromium.org>

Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
2021-03-03 14:51:06 -05:00
Simon Glass
401d1c4f5d common: Drop asm/global_data.h from common header
Move this out of the common header and include it only where needed.  In
a number of cases this requires adding "struct udevice;" to avoid adding
another large header or in other cases replacing / adding missing header
files that had been pulled in, very indirectly.   Finally, we have a few
cases where we did not need to include <asm/global_data.h> at all, so
remove that include.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
2021-02-02 15:33:42 -05:00
Simon Glass
65e25bea59 dm: Rename DM_GET_DRIVER() to DM_DRIVER_GET()
In the spirit of using the same base name for all of these related macros,
rename this to have the operation at the end. This is not widely used so
the impact is fairly small.

Signed-off-by: Simon Glass <sjg@chromium.org>
2021-01-05 12:26:35 -07:00
Simon Glass
0fd3d91152 dm: Use access methods for dev/uclass private data
Most drivers use these access methods but a few do not. Update them.

In some cases the access is not permitted, so mark those with a FIXME tag
for the maintainer to check.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Pratyush Yadav <p.yadav@ti.com>
2021-01-05 12:24:40 -07:00
Simon Glass
d1998a9fde dm: treewide: Rename ofdata_to_platdata() to of_to_plat()
This name is far too long. Rename it to remove the 'data' bits. This makes
it consistent with the platdata->plat rename.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-12-13 16:51:09 -07:00
Simon Glass
c69cda25c9 dm: treewide: Rename dev_get_platdata() to dev_get_plat()
Rename this to be consistent with the change from 'platdata'.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-12-13 16:51:09 -07:00
Simon Glass
caa4daa2ae dm: treewide: Rename 'platdata' variables to just 'plat'
We use 'priv' for private data but often use 'platdata' for platform data.
We can't really use 'pdata' since that is ambiguous (it could mean private
or platform data).

Rename some of the latter variables to end with 'plat' for consistency.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-12-13 16:51:08 -07:00
Simon Glass
41575d8e4c dm: treewide: Rename auto_alloc_size members to be shorter
This construct is quite long-winded. In earlier days it made some sense
since auto-allocation was a strange concept. But with driver model now
used pretty universally, we can shorten this to 'auto'. This reduces
verbosity and makes it easier to read.

Coincidentally it also ensures that every declaration is on one line,
thus making dtoc's job easier.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-12-13 08:00:25 -07:00
Patrick Delaunay
8558217153 gpio: Convert to use APIs which support live DT
Use ofnode_ or dev_ APIs instead of fdt_ and fdtdec_ APIs so that the
driver can support live DT.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
2020-12-01 10:33:37 -05:00
Jean-Jacques Hiblot
d4b722e3a8 drivers: gpio: Add a managed API to get a GPIO from the device-tree
Add managed functions to get a gpio from the devce-tree, based on a
property name (minus the '-gpios' suffix) and optionally an index.

When the device is unbound, the GPIO is automatically released and the
data structure is freed.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
2020-09-30 11:55:22 -04:00
Simon Glass
2912686c08 gpio: Add a method to convert a GPIO to ACPI
When generating ACPI tables we need to convert GPIOs in U-Boot to the ACPI
structures required by ACPI. This is a SoC-specific conversion and cannot
be handled by generic code, so add a new GPIO method to do the conversion.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2020-07-17 14:32:24 +08:00
Heiko Schocher
2bd261dd17 gpio: search for gpio label if gpio is not found through bank name
dm_gpio_lookup_name() searches for a gpio through
the bank name. But we have also gpio labels, and it
makes sense to search for a gpio also in the labels
we have defined, if no gpio is found through the
bank name definition.

This is useful for example if you have a wp pin on
different gpios on different board versions.

If dm_gpio_lookup_name() searches also for the gpio labels,
you can give the gpio an unique label name and search
for this label, and do not need to differ between
board revisions.

Signed-off-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
[trini: Don't enable by default]
Signed-off-by: Tom Rini <trini@konsulko.com>
2020-07-07 18:23:37 -04:00
Heiko Schocher
cd2faeba1a gpio-uclass.c: save the GPIOD flags also in the gpio descriptor
save the GPIOD_ flags also in the gpio descriptor.

Signed-off-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Patrick Delaunay <patrick.delaunay@st.com>
Fixes: 788ea83412 ("gpio: add function _dm_gpio_set_dir_flags")
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Walter Lozano <walter.lozano@collabora.com>
2020-07-05 08:06:09 -04:00
Simon Glass
f7ae49fc4f common: Drop log.h from common header
Move this header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-05-18 21:19:18 -04:00
Neil Armstrong
47bd533e9d gpio: emulate open drain & open source in dm_gpio_set_value()
Handle the GPIOD_OPEN_DRAIN & GPIOD_OPEN_SOURCE flags to emulate open drain
and open source by setting the GPIO line as input depending on the
requested value.

The behaviour is taken from the Linux gpiolib.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-05-11 15:12:53 +02:00
Patrick Delaunay
8fd9daf036 gpio: add ops to set dir flags
Add the ops for GPIO driver set_dir_flags() to set the dir flags.
The user can update the direction and configuration
of each GPIO with a only call to dm_gpio_set_dir_flags() or
dm_gpio_set_dir() and respecting the configuration provided by
device tree (saved in desc->flags).

When these optional ops are absent, the gpio uclass use the mandatory
ops (direction_output, direction_input, get_value) and desc->flags
to manage only the main dir flags:
- GPIOD_IS_IN
- GPIOD_IS_OUT
- GPIOD_IS_OUT_ACTIVE
- GPIOD_ACTIVE_LOW

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-04-16 23:06:54 -04:00
Patrick Delaunay
d2c07e56ab gpio: add ops to get dir flags
Add the ops for GPIO driver get_dir_flags(), allows to get dynamically
the current gpio configuration; it is used by the API function
dm_gpio_get_dir_flags().

When these optional ops are absent, the gpio uclass continues to use
the mandatory ops (direction_output, direction_input, get_value) and
value of desc->flags to manage only the main dir flags:
- GPIOD_IS_IN
- GPIOD_IS_OUT
- GPIOD_IS_OUT_ACTIVE
- GPIOD_ACTIVE_LOW

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-04-16 23:06:54 -04:00
Patrick Delaunay
477ca57b9a gpio: add support of new GPIO direction flag
This commit manages the new dir flags that can be used in gpio
specifiers to indicate the pull-up or pull-down resistor
configuration for output gpio (GPIO_PULL_UP, GPIO_PULL_DOWN)
or the Open Drain/Open Source configuration for input gpio
(GPIO_OPEN_DRAIN, GPIO_OPEN_SOURCE).

These flags are already supported in Linux kernel in gpio lib.

This patch only parse and save the direction flags in GPIO
descriptor (desc->flags), it prepares the introduction of new ops
to manage them.
The GPIO uclass supports new GPIO flags from device-tree
(GPIO_XXX define in include/dt-bindings/gpio/gpio.h)
and translate them in the dir flags (GPIOD_XXX):
- GPIO_PULL_UP     => GPIOD_PULL_UP
- GPIO_PULL_DOWN   => GPIOD_PULL_DOWN
- GPIO_OPEN_DRAIN  => GPIOD_OPEN_DRAIN
- GPIO_OPEN_SOURCE => GPIOD_OPEN_SOURCE

This patch also adds protection in the check_dir_flags function for
new invalid configuration of the dir flags.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-04-16 23:06:54 -04:00
Patrick Delaunay
695e5fd546 gpio: update dir_flags management
Update the flag management in GPIO uclass: the desc->flags is always
combined with the requested flags and the GPIO descriptor is updated
for further call.

Add a function dm_gpio_get_dir_flags to get dynamically
the current dir_flags (configuration and value).

This patch prepare introduction of the dir flags support with new ops.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-04-16 23:06:54 -04:00
Patrick Delaunay
9360bb06f1 gpio: add helper GPIOD_FLAGS_OUTPUT
Add a macro to provide the GPIO output value according
the dir flags content.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-04-16 23:06:54 -04:00
Patrick Delaunay
4292fb16bf gpio: add function check_dir_flags
Add a dir flags validity check with a new function
check_dir_flags.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-04-16 23:06:54 -04:00
Patrick Delaunay
788ea83412 gpio: add function _dm_gpio_set_dir_flags
Introduce the function _dm_gpio_set_dir_flags to set dir flags
without check if the GPIO is reserved.

Separate the reserved check for "set_dir" and "set_dir_flags".

This patch is a preliminary step to add new ops.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-04-16 23:06:54 -04:00
Patrick Delaunay
8a9140cd38 gpio: add function _gpio_get_value
Introduce the function _gpio_get_value to get the GPIO value
without check if it is reserved.
This patch prepare new ops introduction.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-04-16 23:06:54 -04:00
Patrick Delaunay
9f2b066cda gpio: add gpio descriptor initialization helper
Add a helper function gpio_desc_init() to initialize the gpio descriptor;
with this function the flags will be always set to 0.

It wasn't the case before this patch in dm_gpio_lookup_name.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
2020-04-16 23:06:54 -04:00
Patrick Delaunay
e3f3a121d8 gpio: remove the open_drain API and ops
This patch removes the ops get_open_drain/set_open_drain
and the API dm_gpio_get_open_drain/dm_gpio_set_open_drain.

The ops only provided in one driver (mpc8xxx gpio) and the
associated API is never called in boards.

This patch prepare a more generic set/get_dir_flags ops,
including the open drain property.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
2020-04-16 23:06:54 -04:00
Simon Glass
093152f275 gpio: Rename free() to rfree()
This function name conflicts with our desire to #define free() to
something else on sandbox. Since it deals with resources, rename it to
rfree().

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-02-05 19:33:46 -07:00
Simon Glass
27084c03d3 spl: Allow tiny printf() to be controlled in SPL and TPL
At present there is only one control for this and it is used for both SPL
and TPL. But SPL might have a lot more space than TPL so the extra cost of
a full printf() might be acceptable.

Split the option into two, providing separate SPL and TPL controls. The
TPL setting defaults to the same as SPL.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2019-10-08 13:57:45 +08:00
Heiko Schocher
49b10cb492 gpio: fixes for gpio-hog support
recently added gpio hog patch was "in discussion"
state with Simon Glass. This patch now adds most
of comments from Simon Glass.

Signed-off-by: Heiko Schocher <hs@denx.de>
2019-07-29 09:32:10 -04:00
Heiko Schocher
5fc7cf8c8e gpio: add gpio-hog support
add gpio-hog support. GPIO hogging is a mechanism
providing automatic GPIO request and configuration
as part of the gpio-controller's driver probe function.

for more infos see:
doc/device-tree-bindings/gpio/gpio.txt

Signed-off-by: Heiko Schocher <hs@denx.de>
Tested-by: Michal Simek <michal.simek@xilinx.com> (zcu102)
Tested-by: Patrick Delaunay <patrick.delaunay@st.com>
2019-07-13 11:11:30 -04:00
Michal Simek
1b4c2aa25b gpio: dm: Support manual relocation for gpio
Relocate gpio ops as was done by:
"dm: Add support for all targets which requires MANUAL_RELOC"
(sha1: 484fdf5ba0)

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2018-07-19 10:49:54 +02:00
Tom Rini
83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00
Mario Six
b053dd7c5a gpio: uclass: Fix debug string
A debug string still has the old name of a function being called; update
it.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Reviewed-by: Simon Glass <sjg@chromium.org>
2018-04-06 20:45:44 -04:00
Masahiro Yamada
fb07f97d6e gpio: add static to get_function()
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-07-06 13:09:36 -04:00
Simon Glass
150c5afe5b dm: gpio: Add live tree support
Add support for requesting GPIOs with a live device tree.

This involves adjusting the function signature for the legacy function
gpio_request_by_name_nodev(), so fix up all callers.

Signed-off-by: Simon Glass <sjg@chromium.org>
Fixes to stm32f746-disco.c:
Signed-off-by: Tom Rini <trini@konsulko.com>
2017-06-01 07:03:10 -06:00
Simon Glass
3a57123e59 dm: gpio: Refactor to prepare for live tree support
Move the main part of the GPIO request function into a separate function
so that it can be used by the live tree function when added. Update the
xlate method to use a node reference.

Update all GPIO drivers to handle the modified xlate() method.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-01 07:03:10 -06:00
Tom Rini
758979101d gpio-uclass.c: Fix comparison of unsigned expression warning
We declare that gpio_base (which is the base for counting gpios, not an
address) is unsigned.  Therefore the comparison with >= 0 is always
true.  As the desire is to allow for this base number to be 0, we can
just drop this check.  Reported by clang-3.8.

Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-05-12 08:37:39 -04:00
Simon Glass
e160f7d430 dm: core: Replace of_offset with accessor
At present devices use a simple integer offset to record the device tree
node associated with the device. In preparation for supporting a live
device tree, which uses a node pointer instead, refactor existing code to
access this field through an inline function.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-02-08 06:12:14 -07:00
mario.six@gdsys.cc
53ecdfb920 dm: gpio: Add methods for open drain setting
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>
2016-06-03 22:13:52 -07:00
Eric Nelson
6c880b7719 dm: gpio: add a default gpio xlate routine
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>
2016-05-17 09:54:43 -06:00
Simon Glass
17c43f1a42 gpio: Use const where possible
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>
2016-03-17 10:27:22 +08:00