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arm64: dts: imx8mq-librem5: Set the DVS voltages lower

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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>
This commit is contained in:
Sebastian Krzyszkowiak 2023-03-09 21:46:01 +01:00 committed by Shawn Guo
parent 41d208c4c8
commit c24a9b698f
2 changed files with 17 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dts
View File

@ -7,7 +7,7 @@
&a53_opp_table {
opp-1000000000 {
opp-microvolt = <1000000>;
opp-microvolt = <950000>;
};
};

22
arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi
View File

@ -839,8 +839,8 @@
regulator-max-microvolt = <1300000>;
regulator-boot-on;
regulator-ramp-delay = <1250>;
rohm,dvs-run-voltage = <900000>;
rohm,dvs-idle-voltage = <850000>;
rohm,dvs-run-voltage = <880000>;
rohm,dvs-idle-voltage = <820000>;
rohm,dvs-suspend-voltage = <800000>;
regulator-always-on;
};
@ -851,8 +851,8 @@
regulator-max-microvolt = <1300000>;
regulator-boot-on;
regulator-ramp-delay = <1250>;
rohm,dvs-run-voltage = <1000000>;
rohm,dvs-idle-voltage = <900000>;
rohm,dvs-run-voltage = <950000>;
rohm,dvs-idle-voltage = <850000>;
regulator-always-on;
};
@ -861,14 +861,14 @@
regulator-min-microvolt = <700000>;
regulator-max-microvolt = <1300000>;
regulator-boot-on;
rohm,dvs-run-voltage = <900000>;
rohm,dvs-run-voltage = <850000>;
};
buck4_reg: BUCK4 {
regulator-name = "buck4";
regulator-min-microvolt = <700000>;
regulator-max-microvolt = <1300000>;
rohm,dvs-run-voltage = <1000000>;
rohm,dvs-run-voltage = <930000>;
};
buck5_reg: BUCK5 {
@ -1403,3 +1403,13 @@
fsl,ext-reset-output;
status = "okay";
};
&a53_opp_table {
opp-1000000000 {
opp-microvolt = <850000>;
};
opp-1500000000 {
opp-microvolt = <950000>;
};
};