acpi_gpiochip_request_interrupts() will check for ACPI handle of
the GPIO chip parent device and bail out if there is none defined.
Thus, has_acpi_companion() is effectively repeating above and
is not needed in the individual driver.

Assigning ->to_irq() unconditionally doesn't change anything, except
an error code, but this we fix as well by propagating it from
platform_get_irq().
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200512182623.54990-2-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Simplify the code which fetches the input clock by using
devm_clk_get_optional(). If no input clock is present
devm_clk_get_optional() will return NULL instead of an error
which matches the behavior of the old code.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200512182623.54990-1-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

gpiochip_set_desc_names() no longer rejects GPIO line name collisions.
Hence GPIO line names are not guaranteed to be globally unique.
In case of multiple GPIO lines with the same name, gpio_name_to_desc()
will return the first match found.

Update the comments for gpio_name_to_desc() and
gpiochip_set_desc_names() to match reality.

Fixes: f881bab0 ("gpio: keep the GPIO line names internal")
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200511101828.30046-1-geert+renesas@glider.beSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Merge tag 'intel-gpio-v5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/andy/linux-gpio-intel into devel

intel-gpio for v5.8-1

* MSI support for Intel Merrifield
* Refactor gpio-pch to be up-to-date with recent kernel APIs
* Miscellaneous cleanups here and there

The following is an automated git shortlog grouped by driver:

ich:
 -  fix a typo

merrifield:
 -  Better show how GPIO and IRQ bases are derived from hardware
 -  Switch over to MSI interrupts

pch:
 -  Use in pch_irq_type() macros provided by IRQ core
 -  Refactor pch_irq_type() to avoid unnecessary locking
 -  Get rid of unneeded variable in IRQ handler
 -  Use BIT() and GENMASK() where it's appropriate

Merge tag 'gpio-updates-for-v5.8-part1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux into devel

gpio updates for v5.8-rc1 - part1

- correct the IRQ type used in to_irq() in gpio-xgene-sb
- add new item to the TODO list
- support building gpio-pl061 as module
- improve pull-up/down support on GPIO expanders in device-tree
- several improvements in gpio-pca953x
- emit a warning for too long GPIO line names
- add MODULE_DEVICE_TABLE to gpio-tegra186
- add support for new variant to gpio-f7188x
- lsgpio can now display bias flags

Add display of the bias flags.
Signed-off-by: NKent Gibson <warthog618@gmail.com>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

Add GPIO support for Fintek F81865 chip.

Datasheet: http://www.hardwaresecrets.com/datasheets/F81865_V028P.pdfSigned-off-by: NPetteri Jokinen <petteri@kiho.fi>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

Export MODULE_DEVICE_TABLE since the driver can be built as a module.
Signed-off-by: NMian Yousaf Kaukab <ykaukab@suse.de>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

When I copied the function prototypes from the GPIO header file into
my own driver, checkpatch yelled at me saying that I shouldn't use use
"unsigned" but instead should say "unsigned int".  Let's make the
header file use "unsigned int" so others who copy like I did won't get
yelled at.
Signed-off-by: NDouglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200428172322.2.Iacb3c8152c3cf9015a91308678155a578b0cc050@changeidSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

The legacy defines GPIOF_DIR_XXX are only for consumers. Document the
proper ones.  Also: don't use "_XXX" since that's harder to find with
"git grep".  Just list both of the values.
Signed-off-by: NDouglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200428172322.1.I396f351e364f3c09df7c7606e79abefb8682c092@changeidSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

After the previous patch the two last parameters of
pca953x_recalc_addr() are unused and so can be dropped.
Tested-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

Some of the chips supported by the pca953x driver need the most
significant bit in the address word set to automatically increment the
address pointer on subsequent reads and writes (example: PCA9505). With
this bit unset the same register is read multiple times on a multi-byte
read sequence. Other chips must not have this bit set and autoincrement
always (example: PCA9555).

Up to now this AI bit was interpreted to be part of the address, which
resulted in inconsistent regmap caching when a register was written with
AI set and then read without it. This happened for the PCA9505 in
pca953x_gpio_set_multiple() where pca953x_read_regs() bulk read from the
cache for registers 0x8-0xc and then wrote to registers 0x88-0x8c. (Side
note: reading 5 values from offset 0x8 yiels OP0 5 times because AI must
be set to get OP0-OP4, which is another bug that is resolved here as a
by-product.) The same problem happens when calls to gpio_set_value() and
gpio_set_array_value() were mixed.

With this patch the AI bit is always set for chips that support it. This
works as there are no code locations that make use of the behaviour with
AI unset (for the chips that support it).

Note that the call to pca953x_setup_gpio() had to be done a bit earlier
to make the NBANK macro work.

The history of this bug is a bit complicated. Commit b32cecb4
("gpio: pca953x: Extract the register address mangling to single
function") changed which chips and functions are affected. Commit
3b00691c ("gpio: pca953x: hack to fix 24 bit gpio expanders") used
some duct tape to make the driver at least appear to work. Commit
49427232 ("gpio: pca953x: Perform basic regmap conversion")
introduced the caching. Commit b4818afe ("gpio: pca953x: Add
set_multiple to allow multiple bits to be set in one write.") introduced
the .set_multiple() callback which didn't work for chips that need the
AI bit which was fixed later for some chips in 8958262a ("gpio:
pca953x: Repair multi-byte IO address increment on PCA9575"). So I'm
sorry, I don't know which commit I should pick for a Fixes: line.
Tested-by: NMarcel Gudert <m.gudert@eckelmann.de>
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

The commit 96d7c7b3 ("gpio: gpio-pca953x, Add get_multiple function")
basically did everything wrong from style and code reuse perspective, i.e.
- it didn't utilize existing PCA953x internal helpers
- it didn't utilize bitmap API
- it misses the point that ilog2(), besides that BANK_SFT is useless,
  can be used in macros
- it has indentation issues.

Rewrite the function completely.

Cc: Paul Thomas <pthomas8589@gmail.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

Fix a spelling typo in gpio-mm-lantiq.c by codespell
s/dont/don't/

Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NDejin Zheng <zhengdejin5@gmail.com>
Link: https://lore.kernel.org/r/20200424154103.10311-3-zhengdejin5@gmail.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

In case of error, the function devm_ioremap() returns NULL pointer not
ERR_PTR(). The IS_ERR() test in the return value check should be
replaced with NULL test.
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20200427110829.154785-1-weiyongjun1@huawei.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Fix a spelling typo in gpio-ftgpio010.c by codespell
s/desireable/desirable/

Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NDejin Zheng <zhengdejin5@gmail.com>
Link: https://lore.kernel.org/r/20200424154103.10311-2-zhengdejin5@gmail.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Consistently use "gc" for "struct gpio *" variables.

This follows the spirit of commit a0b66a73 ("gpio: Rename
variable in core APIs").
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200424141517.11582-1-geert+renesas@glider.beSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Simplify the printing of kernel messages and make the messages more
accurate by using the most appropriate {dev,chip,gpiod}_*() helpers.

Sample impact:

    -gpiochip_setup_dev: registered GPIOs 496 to 511 on device: gpiochip0 (e6050000.gpio)
    +gpio gpiochip0: registered GPIOs 496 to 511 on e6050000.gpio

    -no flags found for gpios
    +gpio-953 (?): no flags found for gpios

    -GPIO line 355 (PCIE/SATA switch) hogged as output/low
    +gpio-355 (PCIE/SATA switch): hogged as output/low
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200424141432.11400-1-geert+renesas@glider.beSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

In some cases indentation makes code harder to read. Amend indentation
in those cases despite of lines go a bit over 80 character limit.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: NSerge Semin <fancer.lancer@gmail.com>
Cc: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200422110654.23442-2-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

When we mask interrupts before sleep, there is no need to have a conjunction
with 0xffffffff since the accepted by dwapb_write() value is 32-bit.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: NSerge Semin <fancer.lancer@gmail.com>
Cc: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200422110654.23442-1-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Some DT authors (including myself) have messed up the length of
gpio-line-names and made it longer than it should be. Add a warning here
so that developers can figure out that they've messed up their DT and
should fix it.

Cc: Alexandru M Stan <amstan@chromium.org>
Signed-off-by: NStephen Boyd <swboyd@chromium.org>
Signed-off-by: NBartosz Golaszewski <bgolaszewski@baylibre.com>

Remove including <linux/version.h> that don't need it.
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20200408070832.137037-1-yuehaibing@huawei.comAcked-by: NAsmaa Mnebhi <Asmaa@mellanox.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

Split out dwapb_get_irq() helper for better readability and maintenance.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-13-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Since we always have a table of IDs compiled in, there is no use
for of_match_ptr() nor ACPI_PTR() call. Besides that it brings
a warning (depending on configuration):

.../gpio-dwapb.c:638:34: warning: ‘dwapb_of_match’ defined but not used [-Wunused-const-variable=]
  638 | static const struct of_device_id dwapb_of_match[] = {
      |                                  ^~~~~~~~~~~~~~

Get rid of them for good.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-12-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

There is no case when no context is provided in the ->suspend() and
->resume() hooks. Moreover, BUG_ON() is harmful to user and makes kernel
inoperable after the crash. Drop the BUG_ON()s for good.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-11-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

More usual pattern is to prepare value and then write it in a single place.
Switch code in dwapb_gpio_set_debounce() to it.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-10-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

IRQ core provides macros such as IRQ_RETVAL().
Convert code to use them.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-9-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Use device_get_match_data() here to simplify the code a bit.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-8-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Convert to use irqd_to_hwirq() instead of direct access to the hwirq member.
Also amend the type of the hwirq holding variable to be irq_hw_number_t.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Cc: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-7-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

GPIO library provides default IRQ resource management hooks,
there is no need to repeat this in the individual driver.

Remove them for good.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-6-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

We switch the default handler to be handle_bad_irq() instead of
handle_level_irq(), though for now apply it later in the code,
to make the difference between IRQ chips more visible.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-5-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Refactor IRQ handler in order to enter and exit chained IRQ by using
respective prologue and epilogue calls.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-4-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Refactor IRQ handler in order to use for_each_set_bit() helper.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-3-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

The commit 3d2613c4
  ("GPIO: gpio-dwapb: Enable platform driver binding to MFD driver")
introduced a use of the platform driver but missed to add the following line
to it:
  MODULE_ALIAS("platform:gpio-dwapb");

Add this to get driver loaded automatically if platform device is registered.

Fixes: 3d2613c4 ("GPIO: gpio-dwapb: Enable platform driver binding to MFD driver")
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: NSerge Semin <fancer.lancer@gmail.com>
Reviewed-by: NSerge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-2-andriy.shevchenko@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Add myself as a co-maintainer of the Synopsis DesignWare APB GPIO driver.
Suggested-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NSerge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Hoan Tran <hoan@os.amperecomputing.com>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-gpio@vger.kernel.org
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200323195401.30338-7-Sergey.Semin@baikalelectronics.ruSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Aside from the APB reference clock DW GPIO controller can have a
dedicated clock connected to setup a debounce time interval for
GPIO-based IRQs. Since this functionality is optional the corresponding
clock source is also optional. Due to this lets handle the debounce
clock in the same way as it has been developed for the APB reference
clock, but using the bulk request/enable-disable methods.
Signed-off-by: NSerge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200323195401.30338-6-Sergey.Semin@baikalelectronics.ruSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

The common clocks kernel framework provides a generic way to use
an optional reference clock sources. If it's utilized there is no
need in checking whether the clock descriptor pointer is actually a
negative error at the moment of the prepare/unprepare clocks method
calling. So if the corresponding clock source is provided, then
getting an error shall actually terminate the device probe procedure.
If it isn't specified then the driver shall proceed with further
initializations.

We'll use the optional clocks getting method to handle the APB reference
clock, which can be provided for instance in the device of-node with
"bus" clock-name.
Signed-off-by: NSerge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200323195401.30338-5-Sergey.Semin@baikalelectronics.ruSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Seeing Hoan has been silent for a long time Linus suggested to me
to be also maintaining the driver. This patch adds myself to the list
of maintainers in the DT schema of the driver.
Suggested-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NSerge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: NRob Herring <robh@kernel.org>
Cc: Hoan Tran <hoan@os.amperecomputing.com>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Link: https://lore.kernel.org/r/20200323195401.30338-4-Sergey.Semin@baikalelectronics.ruSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Port A of the DW GPIO controller may optionally have a debounce
logic enabled if it was synthesized with that functionality enabled.
In this case a dedicated reference clock should be declared in the
node with corresponding "db" name presented in the clock-names
property.
Signed-off-by: NSerge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: NRob Herring <robh@kernel.org>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Link: https://lore.kernel.org/r/20200323195401.30338-3-Sergey.Semin@baikalelectronics.ruSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>

Modern device tree bindings are supposed to be created as YAML-files
in accordance with DT schema. This commit replaces Synopsys DW GPIO
legacy bare text binding with YAML file. As before the binding file
states that the corresponding dts node is supposed to be compatible
with generic DW I2C controller indicated by the "snps,dw-apb-gpio"
compatible string and to provide a mandatory registers memory range.
It may also have an optional clock and reset phandle references.

There must be specified at least one subnode with
"snps,dw-apb-gpio-port" compatible string indicating the GPIO port,
which would actually export the GPIO controller functionality. Such
nodes should have traditional GPIO controller properties together
with optional interrupt-controller attributes if the corresponding
controller was synthesized to detect and report the input values
change to the parental IRQ controller.
Signed-off-by: NSerge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200323195401.30338-2-Sergey.Semin@baikalelectronics.ruSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>