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The fernsehfee3 board uses a Ricoh RN5T618 PMIC to generate various voltages. Board schematics are not available, but the regulator voltages found in /sys/kernel/debug/regulator/regulator_summary match those in meson8m2-mxiii-plus.dts: DCDC1 0 0 0 unknown 1100mV 0mA 0mV 0mV DCDC2 0 0 0 unknown 1150mV 0mA 0mV 0mV DCDC3 0 0 0 unknown 1500mV 0mA 0mV 0mV LDO1 0 0 0 unknown 2900mV 0mA 0mV 0mV LDO2 0 0 0 unknown 1800mV 0mA 0mV 0mV LDO3 0 0 0 unknown 1800mV 0mA 0mV 0mV LDO4 0 0 0 unknown 2850mV 0mA 0mV 0mV LDO5 0 0 0 unknown 1800mV 0mA 0mV 0mV LDORTC1 0 0 0 unknown 2700mV 0mA 0mV 0mV LDORTC2 0 0 0 unknown 900mV 0mA 0mV 0mV This patch takes the following approach: - Copy RN5T618 regulator nodes from meson8m2-mxiii-plus.dts - Remove some of the regulator names, which do not seem to apply - Verify regulator supply relations by starting without any relations (and without regulator-always-on) and seeing what breaks when the kernel turns off "unused" regulators. This results in the following observations: - When LDO1 is turned off, the board resets - When DCDC1, DCDC2, DCDC3, LDO2, or LDO5 are turned off, the board (as observed through the serial port) stops running, so these must stay on at all times. - LDO4 (VCC2V8) appears to be unused on this board. - LDO3 (VCC1V8_USB) must stay on in order for USB to work, both the external USB ports and the internal USB wifi module. The cpu-supply and mali-supply relations are also copied from meson8m2-mxiii-plus.dts Signed-off-by: J. Neuschäfer <j.ne@posteo.net> Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Link: https://lore.kernel.org/r/20250428-fernsehfee-v2-4-293b98a43a91@posteo.net Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
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 reStructuredText 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.