They're still in the operating range according to i.MX 8M Quad
datasheet. There's some headroom added over minimal values to
account for voltage drop.
Operational ranges (min - typ - max [selected]):
- VDD_SOC (BUCK1): 0.81 - 0.9 - 0.99 [0.88]
- VDD_ARM (BUCK2): 0.81 - 0.9 - 1.05 [0.84] (1000MHz)
0.90 - 1.0 - 1.05 [0.93] (1500MHz)
- VDD_GPU (BUCK3): 0.81 - 0.9 - 1.05 [0.85] (800MHz)
0.90 - 1.0 - 1.05 [ -- ] (1000MHz)
- VDD_VPU (BUCK4): 0.81 - 0.9 - 1.05 [ -- ] (550/500/588MHz)
0.90 - 1.0 - 1.05 [0.93] (660/600/800MHz)
Idle power consumption doesn't appear to be influenced much,
but a simple load test (`cat /dev/urandom | pigz - > /dev/null`
combined with running Animatch) seems to show about 0.3W of
difference.
Care is advised, as there may be differences between each
units in how low can they be undervolted - in my experience,
reaching that point usually makes the phone fail to boot.
In my case, it appears that my Birch phone can go down the most.
This is a somewhat conservative set of values that I've seen
working well on all my devices; I haven't tried very hard to
optimize it, so more experiments are welcome.
Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
The Librem 5 r3 ("Dogwood") and r4 ("Evergreen") revisions are quite
similar. Add a shared imx8mq-librem5-r3.dtsi description to be included
in r3 and later dts files in order to avoid duplication.
This is no change in the descriptions but only refactoring.
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Commit 99e71c0292 ("arm64: dts: imx8mq-librem5: Don't mark buck3 as always on")
removed always-on marking from GPU regulator, which is great for power
saving - however it introduces additional i2c0 traffic which can be deadly
for devices from the Dogwood batch.
To workaround the i2c0 shutdown issue on Dogwood, this commit marks
buck3 as always-on again - but only for Dogwood (r3).
Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This is a workaround for a hardware bug in the r3 revision that basically would
stop the system due to traffic on the i2c1 bus. A cpu voltage change would
trigger such traffic and that's what is avoided in order to work around it.
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Add a devicetree description for the Librem 5 phone. 4 hardware revisions
have been available. Some revisions include changes that need different
software to be run. So far, r3 ("Dogwood") is one such example, see:
"Aspen" r0 not supported (very few devices exist)
"Birch" r1 supported by r2
"Chestnut" r2 added by this patch
"Dogwood" r3 added by this patch
"Evergreen" r4 tba / most likely supported by r3
See https://puri.sm/products/librem-5/ for more information.
This boots to a working console with working WWAN modem, wifi usdhc,
IMU sensor device, proximity sensor, haptic motor, gpio keys, GNSS and LEDs.
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Angus Ainslie (Purism) <angus@akkea.ca>
Signed-off-by: Guido Günther <agx@sigxcpu.org>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com> (for the audio part)
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
