From: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@xxxxxxx>
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@xxxxxxx>
Signed-off-by: Martin Kepplinger <martin.kepplinger@xxxxxxx>
---
.../boot/dts/freescale/imx8mq-librem5-r3.dts | 2 +-
.../boot/dts/freescale/imx8mq-librem5.dtsi | 22 ++++++++++++++-----
2 files changed, 17 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dts b/arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dts
index 4533a84fb0b95..077c5cd2586f7 100644
--- a/arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dts
+++ b/arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dts
@@ -7,7 +7,7 @@
&a53_opp_table {
opp-1000000000 {
- opp-microvolt = <1000000>;
+ opp-microvolt = <950000>;
};
};
diff --git a/arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi b/arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi
index 509776a63259b..eaf35cff2f8a6 100644
--- a/arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi
@@ -839,8 +839,8 @@ buck1_reg: BUCK1 {
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 @@ buck2_reg: BUCK2 {
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 @@ buck3_reg: BUCK3 {
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 @@ &wdog1 {
fsl,ext-reset-output;
status = "okay";
};
+
+&a53_opp_table {
+ opp-1000000000 {
+ opp-microvolt = <850000>;
+ };
+
+ opp-1500000000 {
+ opp-microvolt = <950000>;
+ };
+};
--
2.30.2
