The Raspberry Pi 3 has a GPIO expander that controls, among others, the 
activity LED, and the camera connector GPIOs. The GPIO expander on an I2C bus 
that is not directly controlled from the ARM core. The VC4 firmware controls 
the I2C bus, and allows the ARM core to set/get GPIO settings over its mailbox 
interface.

This series adds support for the RPi3 expander.

The driver is ported from the downstream kernel at 
https://github.com/raspberrypi/linux/, branch rpi-4.9.y.

Baruch Siach (3):
  ARM: bcm2835: sync firmware properties with downstream
  dt-bindings: gpio: add raspberry pi GPIO expander binding
  ARM: dts: bcm2837-rpi-3-b: add GPIO expander

Dave Stevenson (1):
  bcm2835-gpio-exp: Driver for GPIO expander via mailbox service

 .../bindings/gpio/brcm,bcm2835-expgpio.txt         |  24 ++
 arch/arm/boot/dts/bcm2837-rpi-3-b.dts              |  10 +
 drivers/gpio/Kconfig                               |   7 +
 drivers/gpio/Makefile                              |   1 +
 drivers/gpio/gpio-bcm-exp.c                        | 254 +++++++++++++++++++++
 include/soc/bcm2835/raspberrypi-firmware.h         |  18 ++
 6 files changed, 314 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/brcm,bcm2835-expgpio.txt
 create mode 100644 drivers/gpio/gpio-bcm-exp.c

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2.15.1