Commit Graph

24 Commits

Author SHA1 Message Date
Linus Torvalds 9798f5178f The is the bulk of GPIO changes for the v4.16 kernel cycle.
Core changes:
 
 - Disallow open drain and open source flags to be set
   simultaneously. This doesn't make electrical sense, and would
   the hardware actually respond to this setting, the result
   would be short circuit.
 
 - ACPI GPIO has a new core infrastructure for handling quirks.
   The quirks are there to deal with broken ACPI tables centrally
   instead of pushing the work to individual drivers. In the world
   of BIOS writers, the ACPI tables are perfect. Until they find a
   mistake in it. When such a mistake is found, we can patch it
   with a quirk. It should never happen, the problem is that it
   happens. So we accomodate for it.
 
 - Several documentation updates.
 
 - Revert the patch setting up initial direction state from
   reading the device. This was causing bad things for drivers
   that can't read status on all its pins. It is only affecting
   debugfs information quality.
 
 - Label descriptors with the device name if no explicit label is
   passed in.
 
 - Pave the ground for transitioning SPI and regulators to use
   GPIO descriptors by implementing some quirks in the device tree
   GPIO parsing code.
 
 New drivers:
 
 - New driver for the Access PCIe IDIO 24 family.
 
 Other:
 
 - Major refactorings and improvements to the GPIO mockup driver
   used for test and verification.
 
 - Moved the AXP209 driver over to pin control since it gained a
   pin control back-end. These patches will appear (with the same
   hashes) in the pin control pull request as well.
 
 - Convert the onewire GPIO driver w1-gpio to use descriptors.
   This is merged here since the W1 maintainers send very few
   pull requests and he ACKed it.
 
 - Start to clean up driver headers using <linux/gpio.h> to just
   use <linux/gpio/driver.h> as appropriate.
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Merge tag 'gpio-v4.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

Pull GPIO updates from Linus Walleij:
 "The is the bulk of GPIO changes for the v4.16 kernel cycle. It is
  pretty calm this time around I think. I even got time to get to things
  like starting to clean up header includes.

  Core changes:

   - Disallow open drain and open source flags to be set simultaneously.
     This doesn't make electrical sense, and would the hardware actually
     respond to this setting, the result would be short circuit.

   - ACPI GPIO has a new core infrastructure for handling quirks. The
     quirks are there to deal with broken ACPI tables centrally instead
     of pushing the work to individual drivers. In the world of BIOS
     writers, the ACPI tables are perfect. Until they find a mistake in
     it. When such a mistake is found, we can patch it with a quirk. It
     should never happen, the problem is that it happens. So we
     accomodate for it.

   - Several documentation updates.

   - Revert the patch setting up initial direction state from reading
     the device. This was causing bad things for drivers that can't read
     status on all its pins. It is only affecting debugfs information
     quality.

   - Label descriptors with the device name if no explicit label is
     passed in.

   - Pave the ground for transitioning SPI and regulators to use GPIO
     descriptors by implementing some quirks in the device tree GPIO
     parsing code.

  New drivers:

   - New driver for the Access PCIe IDIO 24 family.

  Other:

   - Major refactorings and improvements to the GPIO mockup driver used
     for test and verification.

   - Moved the AXP209 driver over to pin control since it gained a pin
     control back-end. These patches will appear (with the same hashes)
     in the pin control pull request as well.

   - Convert the onewire GPIO driver w1-gpio to use descriptors. This is
     merged here since the W1 maintainers send very few pull requests
     and he ACKed it.

   - Start to clean up driver headers using <linux/gpio.h> to just use
     <linux/gpio/driver.h> as appropriate"

* tag 'gpio-v4.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (103 commits)
  gpio: Timestamp events in hardirq handler
  gpio: Fix kernel stack leak to userspace
  gpio: Fix a documentation spelling mistake
  gpio: Documentation update
  gpiolib: remove redundant initialization of pointer desc
  gpio: of: Fix NPE from OF flags
  gpio: stmpe: Delete an unnecessary variable initialisation in stmpe_gpio_probe()
  gpio: stmpe: Move an assignment in stmpe_gpio_probe()
  gpio: stmpe: Improve a size determination in stmpe_gpio_probe()
  gpio: stmpe: Use seq_putc() in stmpe_dbg_show()
  gpio: No NULL owner
  gpio: stmpe: i2c transfer are forbiden in atomic context
  gpio: davinci: Include proper header
  gpio: da905x: Include proper header
  gpio: cs5535: Include proper header
  gpio: crystalcove: Include proper header
  gpio: bt8xx: Include proper header
  gpio: bcm-kona: Include proper header
  gpio: arizona: Include proper header
  gpio: amd8111: Include proper header
  ...
2018-01-31 12:25:27 -08:00
Thomas Gleixner 8880c13734 gpio: brcmstb: Make really use of the new lockdep class
The recent extension of irq_set_lockdep_class() with a second argument
added the new lockdep class to the mrcmstb driver, but used the already
existing lockdep class as second argument, which leaves the new lockdep
class defined but unused.

Use the new lockdep class as that's what the change intended to do.

Fixes: 39c3fd5895 ("kernel/irq: Extend lockdep class for request mutex")
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: linus.walleij@linaro.org
2017-12-29 16:37:09 +01:00
Andrew Lunn 39c3fd5895 kernel/irq: Extend lockdep class for request mutex
The IRQ code already has support for lockdep class for the lock mutex
in an interrupt descriptor. Extend this to add a second class for the
request mutex in the descriptor. Not having a class is resulting in
false positive splats in some code paths.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: linus.walleij@linaro.org
Cc: grygorii.strashko@ti.com
Cc: f.fainelli@gmail.com
Link: https://lkml.kernel.org/r/1512234664-21555-1-git-send-email-andrew@lunn.ch
2017-12-28 12:26:35 +01:00
Pravin Shedge 76bc7f1876 drivers: gpio: remove duplicate includes
These duplicate includes have been found with scripts/checkincludes.pl
but they have been removed manually to avoid removing false positives.

Signed-off-by: Pravin Shedge <pravin.shedge4linux@gmail.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-12-20 13:08:10 +01:00
Doug Berger 4714221b0c gpio: brcmstb: implement suspend/resume/shutdown
This commit corrects problems with the previous wake implementation
by implementing suspend and resume power management operations and
the driver shutdown operation.

Wake masks are used to keep track of which GPIO should wake the
device.  On suspend the GPIO state is saved and the possible wakeup
sources are explicitly unmasked in the hardware. Non-wakeup sources
are explicitly masked so IRQCHIP_MASK_ON_SUSPEND is no longer
necessary.  The saved state of the GPIO is restored upon resume.
It is important not to write to the GPIO status register since this
has the effect of clearing bits.  The status register is explicitly
removed from the register save and restore to ensure this.

The shutdown operation allows the hardware to be put into the same
quiesced state as the suspend operation and removes the need for
the reboot notifier.

Unfortunately, there appears to be some confusion about whether
a pending disabled wake interrupt should wake the system. If a wake
capable interrupt is disabled using the default "lazy disable"
behavior and it is triggered before the suspend_device_irq call
the interrupt hardware will be acknowledged by mask_ack_irq and the
IRQS_PENDING flag is added to its state. However, the IRQS_PENDING
flag of wake interrupts is not checked to prevent the transition to
suspend and the hardware has been acked which prevents its wakeup.
If the lazy disabled interrupt is triggered after the call to
suspend_device_irqs then the wakeup logic will abort the suspend.
The irq_disable method is defined by this GPIO driver to prevent
lazy disable so that the pending hardware state remains asserted
allowing the hardware to wake and providing a consistent behavior.

In addition, the IRQ_DISABLE_UNLAZY flag is set for the non-wake
parent interrupt as a convenience to prevent the need to add code
to the brcmstb_gpio_irq_handler to support "lazy disable" of the
non-wake parent interrupt when it is disabled during suspend and
resume. Chained interrupt parents are not normally disabled, but
these GPIO devices have different parent interrupts for wake and
non-wake handling. It is convenient to mask the non-wake parent
when suspending to preserve the hardware state for proper wakeup
accounting when the driver is resumed.

Signed-off-by: Doug Berger <opendmb@gmail.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-10-31 10:51:40 +01:00
Doug Berger 0ba31dc201 gpio: brcmstb: consolidate interrupt domains
The GPIOLIB IRQ chip helpers were very appealing, but badly broke
the 1:1 mapping between a GPIO controller's device_node and its
interrupt domain.

When another device-tree node references a GPIO device as its
interrupt parent, the irq_create_of_mapping() function looks for
the irq domain of the GPIO device and since all bank irq domains
reference the same GPIO device node it always resolves to the irq
domain of the first bank regardless of which bank the number of
the GPIO should resolve. This domain can only map hwirq numbers
0-31 so interrupts on GPIO above that can't be mapped by the
device-tree.

This commit effectively reverts the patch from Gregory Fong [1]
that was accepted upstream and replaces it with a consolidated
irq domain implementation with one larger interrupt domain per
GPIO controller instance spanning multiple GPIO banks based on
an earlier patch [2] also submitted by Gregory Fong.

[1] https://patchwork.kernel.org/patch/6921561/
[2] https://patchwork.kernel.org/patch/6347811/

Fixes: 19a7b6940b ("gpio: brcmstb: Add interrupt and wakeup source support")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Gregory Fong <gregory.0xf0@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-10-31 10:34:40 +01:00
Doug Berger 633007a36e gpio: brcmstb: correct the configuration of level interrupts
This commit corrects a bug when configuring the GPIO hardware for
IRQ_TYPE_LEVEL_LOW and IRQ_TYPE_LEVEL_HIGH interrupt types. The
hardware is now correctly configured to support those types.

Fixes: 19a7b6940b ("gpio: brcmstb: Add interrupt and wakeup source support")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-10-31 10:30:44 +01:00
Doug Berger 2c218b9f1b gpio: brcmstb: switch to handle_level_irq flow
Reading and writing the gpio bank status register each time a pending
interrupt bit is serviced could cause new pending bits to be cleared
without servicing the associated interrupts.

By using the handle_level_irq flow instead of the handle_simple_irq
flow we get proper handling of interrupt masking as well as acking
of interrupts.  The irq_ack method is added to support this.

Fixes: 19a7b6940b ("gpio: brcmstb: Add interrupt and wakeup source support")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-10-31 10:29:53 +01:00
Doug Berger 142c168e0e gpio: brcmstb: release the bgpio lock during irq handlers
The basic memory-mapped GPIO controller lock must be released
before calling the registered GPIO interrupt handlers to allow
the interrupt handlers to access the hardware.

Examples of why a GPIO interrupt handler might want to access
the GPIO hardware include an interrupt that is configured to
trigger on rising and falling edges that needs to read the
current level of the input to know how to respond, or an
interrupt that causes a change in a GPIO output in the same
bank. If the lock is not released before enterring the handler
the hardware accesses will deadlock when they attempt to grab
the lock.

Since the lock is only needed to protect the calculation of
unmasked pending interrupts create a dedicated function to
perform this and hide the complexity.

Fixes: 19a7b6940b ("gpio: brcmstb: Add interrupt and wakeup source support")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-10-31 10:28:46 +01:00
Doug Berger 0752df6611 gpio: brcmstb: allow all instances to be wakeup sources
This commit allows a wakeup parent interrupt to be shared between
instances.

It also removes the redundant can_wake member of the private data
structure by using whether the parent_wake_irq has been defined to
indicate that the GPIO device can wake.

Fixes: 19a7b6940b ("gpio: brcmstb: Add interrupt and wakeup source support")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-10-31 10:27:59 +01:00
Linus Walleij d74423687f gpio: brcmstb: Do not use gc->pin2mask()
The pin2mask() accessor only shuffles BIT ORDER in big endian systems,
i.e. the bitstuffing is swizzled big endian so "bit 0" is bit 7 or
bit 15 or bit 31 or so.

The brcmstb only uses big endian BYTE ORDER which will be taken car of
by the ->write_reg() callback.

Just use BIT(offset) to assign the bit.

Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-10-25 11:25:39 +02:00
Arvind Yadav ba3e217a57 gpio: brcmstb: Handle return value of devm_kasprintf
devm_kasprintf() can fail here and we must check its return value.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-09-21 14:13:16 +02:00
Masahiro Yamada f89c6eafa3 gpio: brcmstb: check return value of gpiochip_irqchip_add()
Because gpiochip_irqchip_add() may fail, its return value should
be checked.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-08-22 15:10:10 +02:00
Rob Herring 7eb6ce2f27 gpio: Convert to using %pOF instead of full_name
Now that we have a custom printf format specifier, convert users of
full_name to use %pOF instead. This is preparation to remove storing
of the full path string for each node.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Tien Hock Loh <thloh@altera.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Cc: linux-gpio@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-08-14 15:01:12 +02:00
Axel Lin 35b3fc8876 gpio: brcmstb: Return proper error if bank width is invalid
Return proper error in brcmstb_gpio_probe if bank width is invalid.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-04-15 10:09:48 +02:00
Axel Lin b178e7ead0 gpio: brcmstb: Use list_for_each_entry at appropriate places
Use list_for_each_entry to simplify the code a bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-02-25 15:20:43 +01:00
Florian Fainelli ce5a7e8139 gpio: brcmstb: Set endian flags for big-endian MIPS
Broadcom MIPS-based STB chips endianness is configured by boot strap,
which also reverses all bus endianness (i.e., big-endian CPU + big
endian bus ==> native endian I/O).

Other architectures (e.g., ARM) either do not support big endian, or
else leave I/O in little endian mode.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-01-07 16:25:09 +01:00
Linus Walleij 0f4630f372 gpio: generic: factor into gpio_chip struct
The separate struct bgpio_chip has been a pain to handle, both
by being confusingly similar in name to struct gpio_chip and
for being contained inside a struct so that struct gpio_chip
is contained in a struct contained in a struct, making several
steps of dereferencing necessary.

Make things simpler: include the fields directly into
<linux/gpio/driver.h>, #ifdef:ed for CONFIG_GENERIC_GPIO, and
get rid of the <linux/basic_mmio_gpio.h> altogether. Prefix
some of the member variables with bgpio_* and add proper
kerneldoc while we're at it.

Modify all users to handle the change and use a struct
gpio_chip directly. And while we're at it: replace all
container_of() dereferencing by gpiochip_get_data() and
registering the gpio_chip with gpiochip_add_data().

Cc: arm@kernel.org
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Olof Johansson <olof@lixom.net>
Cc: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Cc: Rabin Vincent <rabin@rab.in>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-omap@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: bcm-kernel-feedback-list@broadcom.com
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Acked-by: Liviu Dudau <Liviu.Dudau@arm.com>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2016-01-05 11:21:00 +01:00
Thomas Gleixner bd0b9ac405 genirq: Remove irq argument from irq flow handlers
Most interrupt flow handlers do not use the irq argument. Those few
which use it can retrieve the irq number from the irq descriptor.

Remove the argument.

Search and replace was done with coccinelle and some extra helper
scripts around it. Thanks to Julia for her help!

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
2015-09-16 15:47:51 +02:00
Linus Walleij 5f6f02cd49 Linux 4.2-rc4
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Merge tag 'v4.2-rc4' into devel

Linux 4.2-rc4
2015-08-13 14:42:55 +02:00
Gregory Fong 3afa129a9d gpio: brcmstb: support wakeup from S5 cold boot
For wake from S5, we need to:
- register a reboot handler
- set wakeup capability before requesting IRQ so wakeup count is
  incremented
- mask all GPIO IRQs and clear any pending interrupts during driver
  probe to since no driver will yet be registered to handle any IRQs
  carried over from boot at that time, and it's possible that the
  booted kernel does not request the same IRQ anyway.

This means that /sys/.../power/wakeup_count is valid at boot time, and
we can properly account for S5 wakeup stats. e.g.:

  ### After waking from S5 from a GPIO key
  # cat /sys/bus/platform/drivers/brcmstb-gpio/f04172c0.gpio/power/wakeup
  enabled
  # cat /sys/bus/platform/drivers/brcmstb-gpio/f04172c0.gpio/power/wakeup_count
  1

Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-08-13 13:13:41 +02:00
Gregory Fong 19a7b6940b gpio: brcmstb: Add interrupt and wakeup source support
Uses the gpiolib irqchip helpers.  For this to work, the irq setup
function is called once per bank instead of once per device.  Note
that all known uses of this block have a BCM7120 L2 interrupt
controller as a parent.  Supports interrupts for all GPIOs.

In the IRQ handler, we check for raised IRQs for invalid GPIOs and
warn (ratelimited) if they're encountered.

Also, several drivers (e.g. gpio-keys) allow for GPIOs to be
configured as wakeup sources, and this GPIO controller supports that
through a separate interrupt path.

The de-facto standard DT property "wakeup-source" is checked, since
that indicates whether the GPIO controller hardware can wake.  Uses
the IRQCHIP_MASK_ON_SUSPEND irq_chip flag because UPG GIO doesn't have
any of its own wakeup source configuration.

Aside regarding gpiolib irqchip helpers: It wasn't obvious (to me)
that you can have multiple chained irqchips and associated IRQ domains
for a single parent IRQ, and as long as the xlate function is written
correctly, a GPIO IRQ request end up checking the correct domain and
will get associated with the correct IRQ.  What helps make this clear
is to read
  drivers/gpio/gpiolib-of.c:
   - of_gpiochip_find_and_xlate()
   - of_get_named_gpiod_flags()
  drivers/gpio/gpiolib.c:
   - gpiochip_find()

Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-08-13 13:13:26 +02:00
Gregory Fong 2252607d32 gpio: brcmstb: fix null ptr dereference in driver remove
If a failure occurs during probe, brcmstb_gpio_remove() is called. In
remove, we call platform_get_drvdata(), but at the time of failure in
the probe the driver data hadn't yet been set which leads to a NULL
ptr dereference in the remove's list_for_each.  Call
platform_set_drvdata() and set up list head right after allocating the
priv struct to both avoid the null pointer dereference that could
occur today.  To guard against potential future changes, check for
null pointer in remove.

Reported-by: Tim Ross <tross@broadcom.com>
Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-07-16 00:12:24 +02:00
Gregory Fong 3b0213d56e gpio: Add GPIO support for Broadcom STB SoCs
This adds support for the GPIO IP "UPG GIO" used on
Broadcom STB SoCs (BCM7XXX and some others). Uses
basic_mmio_gpio to instantiate a gpio_chip for each bank.
The driver assumes that it handles the base set of GPIOs
on the system and that it can start its numbering sequence
from 0, so any GPIO expanders used with it must dynamically
assign GPIO numbers after this driver has finished
registering its GPIOs.

Does not implement the interrupt-controller portion yet,
will be done in a future commit.

v2:
- change include to use <linux/gpio/driver.h> instead of
  <linux/gpio.h>
- get rid of unnecessary imask member in struct bank
- rename GPIO_PER_BANK -> MAX_GPIO_PER_BANK
- always have 32 GPIOs per bank and add 'width' member in
  struct bank to hold actual number of GPIOs in use
- mark of_match table as const

List-usage-fixed-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-06-02 15:36:22 +02:00