[PATCH v5 0/4] VIM3: add support for checking 'Function' button state

[Marek Szyprowski]

Hi All,

This patchset adds all building blocks needed for checking the 'Function'
button state in the boot script on Amlogic A311D based VIM3 board. This
button is connected to the ADC lines of the SoC, so it required to enable
meson SARADC, the clocks needed for it and a simple button-adc drivers.

Once applied, one can use following commands in the boot scripts:
-->8---
echo Checking Func button state: \\c
if button Function
then
	echo Selected alternative boot
	...
fi
--->8---

Best regards
Marek Szyprowski
Samsung R&D Institute Poland


Changelog:
v5:
- rebased onto latest uboot-amlogic/u-boot-amlogic-next branch
- synchronized adc-keys binding with the recent version from the Linux
  kernel
- updated adc-keys driver to match behavior from dt-bindings
- added a patch for meson-saradc driver to register vdd reference supply
  to the ADC framework

v4: https://lists.denx.de/pipermail/u-boot/2020-December/435641.html
- rebased onto uboot-amlogic/u-boot-amlogic-next and dropped merged patches
- added adc-keys bindings docs (copied from Linux kernel)
- minor code adjustments pointed by Simon
- enabled driver also in khadas-vim3l_defconfig

v3: https://lists.denx.de/pipermail/u-boot/2020-December/435072.html
- removed 'button' env variable
- extended kconfig and patch descriptions

v2: https://lists.denx.de/pipermail/u-boot/2020-December/434991.html
- removed Change-Id tags
- split defconfig changes into ADC and button related

v1: https://lists.denx.de/pipermail/u-boot/2020-December/434875.html
- initial submission


Patch summary:

Marek Szyprowski (4):
  dt-bindings: input: adc-keys bindings documentation
  button: add a simple Analog to Digital Converter device based button
    driver
  adc: meson-saradc: add support for getting reference voltage value
  configs: khadas-vim3(l): enable Function button support

 configs/khadas-vim3_defconfig               |   2 +
 configs/khadas-vim3l_defconfig              |   2 +
 doc/device-tree-bindings/input/adc-keys.txt |  67 +++++++++
 drivers/adc/meson-saradc.c                  |  21 +++
 drivers/button/Kconfig                      |   8 +
 drivers/button/Makefile                     |   1 +
 drivers/button/button-adc.c                 | 156 ++++++++++++++++++++
 7 files changed, 257 insertions(+)
 create mode 100644 doc/device-tree-bindings/input/adc-keys.txt
 create mode 100644 drivers/button/button-adc.c

-- 
2.17.1