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

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>

diff --git a/arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dts b/arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dts
index 4533a84fb0b95f589ed64d83dc1fcde65d6ecd5b..077c5cd2586f755fe09b989200917b0a571f1b5b 100644 (file)
--- 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 509776a63259b4ec7c6ebabfc1f2c99211b57a71..eaf35cff2f8a62eb39fa5b5cd4b05b3ed8652240 100644 (file)
--- a/arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi
@@ -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>;
+       };
+};