gpio: pcie-idio-24: Migrate to the regmap API

The regmap API supports IO port accessors so we can take advantage of
regmap abstractions rather than handling access to the device registers
directly in the driver.

For the PCIe-IDIO-24 series of devices, the following BARs are
available:

BAR[0]: memory mapped PEX8311
BAR[1]: I/O mapped PEX8311
BAR[2]: I/O mapped card registers

There are 24 FET Output lines, 24 Isolated Input lines, and 8 TTL/CMOS
lines (which may be configured for either output or input). The GPIO
lines are exposed by the following card registers:

Base +0x0-0x2 (Read/Write): FET Outputs
Base +0xB (Read/Write): TTL/CMOS
Base +0x4-0x6 (Read): Isolated Inputs
Base +0x7 (Read): TTL/CMOS

In order for the device to support interrupts, the PLX PEX8311 internal
PCI wire interrupt and local interrupt input must first be enabled.

The following card registers for Change-Of-State may be used:

Base +0x8-0xA (Read): COS Status Inputs
Base +0x8-0xA (Write): COS Clear Inputs
Base +0xB (Read): COS Status TTL/CMOS
Base +0xB (Write): COS Clear TTL/CMOS
Base +0xE (Read/Write): COS Enable

The COS Enable register is used to enable/disable interrupts and
configure the interrupt levels; each bit maps to a group of eight inputs
as described below:

Bit 0: IRQ EN Rising Edge IN0-7
Bit 1: IRQ EN Rising Edge IN8-15
Bit 2: IRQ EN Rising Edge IN16-23
Bit 3: IRQ EN Rising Edge TTL0-7
Bit 4: IRQ EN Falling Edge IN0-7
Bit 5: IRQ EN Falling Edge IN8-15
Bit 6: IRQ EN Falling Edge IN16-23
Bit 7: IRQ EN Falling Edge TTL0-7

An interrupt is asserted when a change-of-state matching the interrupt
level configuration respective for a particular group of eight inputs
with enabled COS is detected.

The COS Status registers may be read to determine which inputs have
changed; if interrupts were enabled, an IRQ will be generated for the
set bits in these registers. Writing the value read from the COS Status
register back to the respective COS Clear register will clear just those
interrupts.

Reviewed-by: Michael Walle <michael@walle.cc>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/3091e387b1d2eac011a1d84e493663aa2acf982e.1680708357.git.william.gray@linaro.org/
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

gpio: pcie-idio-24: Prune superfluous license boilerplate

The SPDX License Identifier line renders the GPL boilerplate text
superfluous, so let's remove it.

Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

gpio: pcie-idio-24: Convert to immutable irq_chip

Convert the driver to immutable irq-chip with a bit of
intuition.

Cc: Marc Zyngier <maz@kernel.org>
Acked-by: William Breathitt Gray <william.gray@linaro.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

gpio: Bulk conversion to generic_handle_domain_irq()

Wherever possible, replace constructs that match either
generic_handle_irq(irq_find_mapping()) or
generic_handle_irq(irq_linear_revmap()) to a single call to
generic_handle_domain_irq().

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>

gpio: pcie-idio-24: Enable PEX8311 interrupts

This enables the PEX8311 internal PCI wire interrupt and the PEX8311
local interrupt input so the local interrupts are forwarded to the PCI.

Fixes: 585562046628 ("gpio: Add GPIO support for the ACCES PCIe-IDIO-24 family")
Cc: stable@vger.kernel.org
Signed-off-by: Arnaud de Turckheim <quarium@gmail.com>
Reviewed-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

gpio: pcie-idio-24: Fix IRQ Enable Register value

This fixes the COS Enable Register value for enabling/disabling the
corresponding IRQs bank.

Fixes: 585562046628 ("gpio: Add GPIO support for the ACCES PCIe-IDIO-24 family")
Cc: stable@vger.kernel.org
Signed-off-by: Arnaud de Turckheim <quarium@gmail.com>
Reviewed-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

gpio: pcie-idio-24: Fix irq mask when masking

Fix the bitwise operation to remove only the corresponding bit from the
mask.

Fixes: 585562046628 ("gpio: Add GPIO support for the ACCES PCIe-IDIO-24 family")
Cc: stable@vger.kernel.org
Signed-off-by: Arnaud de Turckheim <quarium@gmail.com>
Reviewed-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

gpio: pcie-idio-24: Use irqchip template

This makes the driver use the irqchip template to assign
properties to the gpio_irq_chip instead of using the
explicit call to gpiochip_irqchip_add().

The irqchip is instead added while adding the gpiochip.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Cc: William Breathitt Gray <vilhelm.gray@gmail.com>
Link: https://lore.kernel.org/r/20200722110027.192782-1-linus.walleij@linaro.org

gpio: pcie-idio-24: utilize for_each_set_clump8 macro

Replace verbose implementation in get_multiple/set_multiple callbacks
with for_each_set_clump8 macro to simplify code and improve clarity.

Link: http://lkml.kernel.org/r/d5d22fa9809dcf8330f4381dbe7e7ca37990e79f.1570641097.git.vilhelm.gray@gmail.com
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Mathias Duckeck <m.duckeck@kunbus.de>
Cc: Morten Hein Tiljeset <morten.tiljeset@prevas.dk>
Cc: Phil Reid <preid@electromag.com.au>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

gpio: Use new GPIO_LINE_DIRECTION

It's hard for occasional GPIO code reader/writer to know if values 0/1
equal to IN or OUT. Use defined GPIO_LINE_DIRECTION_IN and
GPIO_LINE_DIRECTION_OUT to help them out.

NOTE - for gpio-amd-fch and gpio-bd9571mwv:
This commit also changes the return value for direction get to equal 1
for direction INPUT. Prior this commit these drivers might have
returned some other positive value but 1 for INPUT.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Acked-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Acked-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

gpio: pcie-idio-24: Mask read inputs for get_multiple

This patch masks the read inputs with the word mask in order to ensure
only requested input states are returned in the bits array.

Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

gpio: pcie-idio-24: Fix off-by-one error in get_multiple loop

The PCIe-IDIO-24 features 8 bits of TTL GPIO which may be configured for
output or input. This patch fixes an off-by-one error in the loop
conditional for the get_multiple callback so that the TTL GPIO are
handled.

Fixes: ca37081595a2 ("gpio: pcie-idio-24: Implement get_multiple/set_multiple callbacks")
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

gpio: pcie-idio-24: Fix port memory offset for get_multiple/set_multiple callbacks

The ioread8/iowrite8 functions expect a memory offset argument. This
patch fixes the ports array to provide the memory addresses of the
respective device I/O registers.

Fixes: ca37081595a2 ("gpio: pcie-idio-24: Implement get_multiple/set_multiple callbacks")
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

gpio: pcie-idio-24: Implement get_multiple/set_multiple callbacks

The ACCES I/O PCIe-IDIO-24 series of devices provides 24
optically-isolated digital I/O accessed via six 8-bit ports. Since eight
input lines are acquired on a single port input read -- and similarly
eight output lines are set on a single port output write -- the
PCIe-IDIO-24 GPIO driver may improve multiple I/O reads/writes by
utilizing a get_multiple/set_multiple callbacks. This patch implements
the idio_24_gpio_get_multiple function which serves as the respective
get_multiple callback, and implements the idio_24_gpio_set_multiple
function which serves as the respective set_multiple callback.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

gpio: Add GPIO support for the ACCES PCIe-IDIO-24 family

The ACCES PCIe-IDIO-24 device provides 56 lines of digital I/O (24 lines
of optically-isolated non-polarized digital inputs for AC and DC control
signals, 24 lines of isolated solid state FET digital outputs, and 8
non-isolated TTL/CMOS compatible programmable I/O). An interrupt is
generated when any of the inputs change state (low to high or high to
low).

Input filter control is not supported by this driver, and input filters
are deactivated by this driver. These devices are capable of
get_multiple and set_multiple functionality, but these functions have
not yet been implemented for this driver. Change-Of-State (COS)
detection functionality may be configured to fire interrupts on
exclusively rising/falling edges, but this driver currently only
implements COS detection for either both edges or none.

Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>