5500f823db
The 96Boards specification expects a 1.8V power rail on the low-speed
expansion connector that is able to provide at least 0.18W / 100 mA.
According to the DB410c hardware user manual this is done by connecting
both L15 and L16 in parallel with up to 55mA each (for 110 mA total) [1].
Unfortunately the current regulator setup in the DB410c device tree
does not implement the specification correctly and only provides 5 mA:
- Only L15 is marked always-on, so L16 is never enabled.
- Without specifying a load the regulator is put into LPM where
it can only provide 5 mA.
Fix this by:
- Adding proper voltage constraints for L16.
- Making L16 always-on.
- Adding regulator-system-load for both L15 and L16. 100 mA should be
available in total, so specify 50 mA for each. (The regulator
hardware can only be in normal (55 mA) or low-power mode (5 mA) so
this will actually result in the expected 110 mA total...)
[1]: https://www.96boards.org/documentation/consumer/dragonboard/dragonboard410c/hardware-docs/hardware-user-manual.md.html#power-supplies
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Fixes: 828dd5d66f ("arm64: dts: apq8016-sbc: make 1.8v available on LS expansion")
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230510-msm8916-regulators-v1-2-54d4960a05fc@gerhold.net
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.