From the AMD BKDG, if WAKE_INT_MASTER_REG.MaskStsEn is set, a software
write to the debounce registers of *any* gpio will block wake/interrupt
status generation for *all* gpios for a length of time that depends on
WAKE_INT_MASTER_REG.MaskStsLength[11:0].  During this period the Interrupt
Delivery bit (INTERRUPT_ENABLE) will read as 0.

In commit 4c1de0414a1340 ("pinctrl/amd: poll InterruptEnable bits in
enable_irq") we tried to fix this same "gpio Interrupts are blocked
immediately after writing debounce registers" problem, but incorrectly
assumed it only affected the gpio whose debounce was being configured
and not ALL gpios.

To solve this for all gpios, we move the polling loop from
amd_gpio_irq_enable() to amd_gpio_irq_set_type(), while holding the gpio
spinlock.  This ensures that another gpio operation (e.g.
amd_gpio_irq_unmask()) can read a temporarily disabled IRQ and
incorrectly disable it while trying to modify some other register bits.

Fixes: 4c1de0414a1340 pinctrl/amd: poll InterruptEnable bits in enable_irq
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

The AMD pinctrl driver demultiplexes GPIO interrupts and fires off their
individual handlers.

If one of these GPIO irqs is configured as a level interrupt, and its
downstream handler is a threaded ONESHOT interrupt, the GPIO interrupt
source is masked by handle_level_irq() until the eventual return of the
threaded irq handler.  During this time the level GPIO interrupt status
will still report as high until the actual gpio source is cleared - both
in the individual GPIO interrupt status bit (INTERRUPT_STS_OFF) and in
its corresponding "WAKE_INT_STATUS_REG" bit.

Thus, if another GPIO interrupt occurs during this time,
amd_gpio_irq_handler() will see that the (masked-and-not-yet-cleared)
level irq is still pending and incorrectly call its handler again.

To fix this, have amd_gpio_irq_handler() check for both interrupts status
and mask before calling generic_handle_irq().

Note: Is it possible that this bug was the source of the interrupt storm
on Ryzen when using chained interrupts before commit ba714a9c1dea85
("pinctrl/amd: Use regular interrupt instead of chained")?

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

According to the AMD BKDG, the GPIO ActiveLevel bits (10:9) map to:
 00 Active High
 01 Active Low
 10 Active on both edges iff LevelTrig (bit 8) == 0
 11 Reserved

The current code has a bug where it interprets 00 => Active Low, and
01 => Active High.

Fix the bug, restrict "Active on both" to just the edge trigger case, and
refactor a bit to make the logic more readable.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

In certain cases interrupt enablement will be delayed relative to when
the InterruptEnable bits are written.  One example of this is when
a GPIO's "debounce" logice is first enabled.  After enabling debounce,
there is a 900 us "warm up" period during which InterruptEnable[0]
(bit 11) will read as 0 despite being written 1.  During this time
InterruptSts will not be updated, nor will interrupts be delivered, even
if the GPIO's interrupt configuration has been written to the register.

To work around this delay, poll the InterruptEnable bits after setting
them to ensure interrupts have truly been enabled in hardware before
returning from the irq_enable handler.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

On boot, gpiochip_add_data() initializes the FLAG_IS_OUT bit in
desc->flags iff its gpio_chip does not have ->direction_input() handler,
else it is initialized to 0, which implies the GPIO is an "input".

Later, the sysfs "direction" handler will use gpiod_get_direction() to
get the current direction, but if no ->get_direction() handler is
installed, the result will just be the current (initial) value of flags,
which will always be OUT irregardless of the initial register value.

Add a get_direction() handler to pinctrl-amd to fix this and always
provide the correct value for direction.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Pull pin control updates from Linus Walleij:
 "This is the bulk of pin control changes for the v4.15 kernel cycle:

  Core:

   - The pin control Kconfig entry PINCTRL is now turned into a
     menuconfig option. This obviously has the implication of making the
     subsystem menu visible in menuconfig. This is happening because of
     two things:

      (a) Intel have started to deploy and depend on pin controllers in
          a way that is affecting users directly. This happens on the
          highly integrated laptop chipsets named after geographical
          places: baytrail, broxton, cannonlake, cedarfork, cherryview,
          denverton, geminilake, lewisburg, merrifield, sunrisepoint...
          It started a while back and now it is ever more evident that
          this is crucial infrastructure for x86 laptops and not an
          embedded obscurity anymore. Users need to be aware.

      (b) Pin control expanders on I2C and SPI that are arch-agnostic.
          Currently Semtech SX150X and Microchip MCP28x08 but more are
          expected. Users will have to be able to configure these in
          directly for their set-up.

   - Just go and select GPIOLIB now that we made sure that GPIOLIB is a
     very vanilla subsystem. Do not depend on it, if we need it, select
     it.

   - Exposing the pin control subsystem in menuconfig uncovered a bunch
     of obscure bugs that are now hopefully fixed, all more or less
     pertaining to Blackfin.

   - Unified namespace for cross-calls between pin control and GPIO.

   - New support for clock skew/delay generic DT bindings and generic
     pin config options for this.

   - Minor documentation improvements.

  Various:

   - The Renesas SH-PFC pin controller has evolved a lot. It seems
     Renesas are churning out new SoCs by the minute.

   - A bunch of non-critical fixes for the Rockchip driver.

   - Improve the use of library functions instead of open coding.

   - Support the MCP28018 variant in the MCP28x08 driver.

   - Static constifying"

* tag 'pinctrl-v4.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (91 commits)
  pinctrl: gemini: Fix missing pad descriptions
  pinctrl: Add some depends on HAS_IOMEM
  pinctrl: samsung/s3c24xx: add CONFIG_OF dependency
  pinctrl: gemini: Fix GMAC groups
  pinctrl: qcom: spmi-gpio: Add pmi8994 gpio support
  pinctrl: ti-iodelay: remove redundant unused variable dev
  pinctrl: max77620: Use common error handling code in max77620_pinconf_set()
  pinctrl: gemini: Implement clock skew/delay config
  pinctrl: gemini: Use generic DT parser
  pinctrl: Add skew-delay pin config and bindings
  pinctrl: armada-37xx: Add edge both type gpio irq support
  pinctrl: uniphier: remove eMMC hardware reset pin-mux
  pinctrl: rockchip: Add iomux-route switching support for rk3288
  pinctrl: intel: Add Intel Cedar Fork PCH pin controller support
  pinctrl: intel: Make offset to interrupt status register configurable
  pinctrl: sunxi: Enforce the strict mode by default
  pinctrl: sunxi: Disable strict mode for old pinctrl drivers
  pinctrl: sunxi: Introduce the strict flag
  pinctrl: sh-pfc: Save/restore registers for PSCI system suspend
  pinctrl: sh-pfc: r8a7796: Use generic IOCTRL register description
  ...

Pull GPIO updates from Linus Walleij:
 "This is the bulk of GPIO changes for the v4.15 kernel cycle:

  Core:

   - Fix the semantics of raw GPIO to actually be raw. No inversion
     semantics as before, but also no open draining, and allow the raw
     operations to affect lines used for interrupts as the caller
     supposedly knows what they are doing if they are getting the big
     hammer.

   - Rewrote the __inner_function() notation calls to names that make
     more sense. I just find this kind of code disturbing.

   - Drop the .irq_base() field from the gpiochip since now all IRQs are
     mapped dynamically. This is nice.

   - Support for .get_multiple() in the core driver API. This allows us
     to read several GPIO lines with a single register read. This has
     high value for some usecases: it can be used to create
     oscilloscopes and signal analyzers and other things that rely on
     reading several lines at exactly the same instant. Also a generally
     nice optimization. This uses the new assign_bit() macro from the
     bitops lib that was ACKed by Andrew Morton and is implemented for
     two drivers, one of them being the generic MMIO driver so everyone
     using that will be able to benefit from this.

   - Do not allow requests of Open Drain and Open Source setting of a
     GPIO line simultaneously. If the hardware actually supports
     enabling both at the same time the electrical result would be
     disastrous.

   - A new interrupt chip core helper. This will be helpful to deal with
     "banked" GPIOs, which means GPIO controllers with several logical
     blocks of GPIO inside them. This is several gpiochips per device in
     the device model, in contrast to the case when there is a 1-to-1
     relationship between a device and a gpiochip.

  New drivers:

   - Maxim MAX3191x industrial serializer, a very interesting piece of
     professional I/O hardware.

   - Uniphier GPIO driver. This is the GPIO block from the recent
     Socionext (ex Fujitsu and Panasonic) platform.

   - Tegra 186 driver. This is based on the new banked GPIO
     infrastructure.

  Other improvements:

   - Some documentation improvements.

   - Wakeup support for the DesignWare DWAPB GPIO controller.

   - Reset line support on the DesignWare DWAPB GPIO controller.

   - Several non-critical bug fixes and improvements for the Broadcom
     BRCMSTB driver.

   - Misc non-critical bug fixes like exotic errorpaths, removal of dead
     code etc.

   - Explicit comments on fall-through switch() statements"

* tag 'gpio-v4.15-1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (65 commits)
  gpio: tegra186: Remove tegra186_gpio_lock_class
  gpio: rcar: Add r8a77995 (R-Car D3) support
  pinctrl: bcm2835: Fix some merge fallout
  gpio: Fix undefined lock_dep_class
  gpio: Automatically add lockdep keys
  gpio: Introduce struct gpio_irq_chip.first
  gpio: Disambiguate struct gpio_irq_chip.nested
  gpio: Add Tegra186 support
  gpio: Export gpiochip_irq_{map,unmap}()
  gpio: Implement tighter IRQ chip integration
  gpio: Move lock_key into struct gpio_irq_chip
  gpio: Move irq_valid_mask into struct gpio_irq_chip
  gpio: Move irq_nested into struct gpio_irq_chip
  gpio: Move irq_chained_parent to struct gpio_irq_chip
  gpio: Move irq_default_type to struct gpio_irq_chip
  gpio: Move irq_handler to struct gpio_irq_chip
  gpio: Move irqdomain into struct gpio_irq_chip
  gpio: Move irqchip into struct gpio_irq_chip
  gpio: Introduce struct gpio_irq_chip
  pinctrl: armada-37xx: remove unused variable
  ...

In order to consolidate the multiple ways to associate an IRQ chip with
a GPIO chip, move more fields into the new struct gpio_irq_chip.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

On Asus laptop models X505BA, X505BP, X542BA and X542BP, the i2c-hid
touchpad (using a GPIO for interrupts) becomes unresponsive after a
few minutes of usage, or after placing two fingers on the touchpad,
which seems to have the effect of queuing up a large amount of input
data to be transferred.

When the touchpad is in unresponsive state, we observed that the GPIO
level-triggered interrupt is still at it's active level, however the
pinctrl-amd driver is not receiving/dispatching more interrupts at this
point.

After the initial interrupt arrives, amd_gpio_irq_mask() is called
however we then see amd_gpio_irq_handler() being called repeatedly for
the same irq; the interrupt mask is not taking effect because of the
following sequence of events:
 - amd_gpio_irq_handler fires, reads and caches pin reg
 - amd_gpio_irq_handler calls generic_handle_irq()
 - During IRQ handling, amd_gpio_irq_mask() is called and modifies pin reg
 - amd_gpio_irq_handler clears interrupt by writing cached value

The stale cached value written at the final stage undoes the masking.
Fix this by re-reading the register before clearing the interrupt.

I also spotted that the interrupt-clearing code can race against
amd_gpio_irq_mask() / amd_gpio_irq_unmask(), so add locking there.
Presumably this race was leading to the loss of interrupts.

After these changes, the touchpad appears to be working fine.

Signed-off-by: Daniel Drake <drake@endlessm.com>
Acked-by: Shah, Nehal-bakulchandra <Nehal-Bakulchandra.shah@amd.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>