gpio: realtek: Add driver for Realtek DHC RTD1625 SoC

Add support for the GPIO controller found on Realtek DHC RTD1625 SoCs.

Unlike the existing Realtek GPIO driver (drivers/gpio/gpio-rtd.c),
which manages pins via shared bank registers, the RTD1625 introduces
a per-pin register architecture. Each GPIO line now has its own
dedicated 32-bit control register to manage configuration independently,
including direction, output value, input value, interrupt enable, and
debounce. Therefore, this distinct hardware design requires a separate
driver.

The RTD1625 GPIO controller has a hardware quirk where both 'assert'
and 'de-assert' interrupts are fired simultaneously on any edge toggle.
The driver works around this quirk to correctly handle edge interrupts.

Interrupt support is optional for this device, matching the dt-bindings.
If the interrupts property is not provided, the driver simply skips IRQ
initialization and operates purely as a basic GPIO controller.

Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Tzuyi Chang <tychang@realtek.com>
Co-developed-by: Yu-Chun Lin <eleanor.lin@realtek.com>
Signed-off-by: Yu-Chun Lin <eleanor.lin@realtek.com>
Reviewed-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Link: https://patch.msgid.link/20260726125209.140307-10-eleanor.lin@realtek.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

0 files changed, 0 insertions, 0 deletions