[ Upstream commit 26d65140e92a626e39c73c9abf769fd174bf5076 ]
Amlogic's vendor kernel defines an OPP for the GPU on Meson8b boards with a voltage of 1.15V. It turns out that the vendor kernel relies on the bootloader to set up the voltage. The bootloader however sets a fixed voltage of 1.10V.
Amlogic's patched u-boot sources (uboot-2015-01-15-23a3562521) confirm this: $ grep -oiE "VDD(EE|AO)_VOLTAGE[ ]+[0-9]+" board/amlogic/configs/m8b_* board/amlogic/configs/m8b_m100_v1.h:VDDAO_VOLTAGE 1100 board/amlogic/configs/m8b_m101_v1.h:VDDAO_VOLTAGE 1100 board/amlogic/configs/m8b_m102_v1.h:VDDAO_VOLTAGE 1100 board/amlogic/configs/m8b_m200_v1.h:VDDAO_VOLTAGE 1100 board/amlogic/configs/m8b_m201_v1.h:VDDEE_VOLTAGE 1100 board/amlogic/configs/m8b_m201_v1.h:VDDEE_VOLTAGE 1100 board/amlogic/configs/m8b_m202_v1.h:VDDEE_VOLTAGE 1100
Another hint at this is the VDDEE voltage on the EC-100 and Odroid-C1 boards. The VDDEE regulator supplies the Mali GPU. It's basically a copy of the VCCK (CPU supply) which means it's limited to 0.86V to 1.14V.
Update the operating voltage of the Mali GPU on Meson8b to 1.10V so it matches with what the vendor u-boot sets.
Fixes: c3ea80b6138cae ("ARM: dts: meson8b: add the Mali-450 MP2 GPU") Signed-off-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Signed-off-by: Kevin Hilman khilman@baylibre.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm/boot/dts/meson8b.dtsi | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/arm/boot/dts/meson8b.dtsi b/arch/arm/boot/dts/meson8b.dtsi index fe84a8c3ce81..6b80aff32fc2 100644 --- a/arch/arm/boot/dts/meson8b.dtsi +++ b/arch/arm/boot/dts/meson8b.dtsi @@ -163,23 +163,23 @@
opp-255000000 { opp-hz = /bits/ 64 <255000000>; - opp-microvolt = <1150000>; + opp-microvolt = <1100000>; }; opp-364300000 { opp-hz = /bits/ 64 <364300000>; - opp-microvolt = <1150000>; + opp-microvolt = <1100000>; }; opp-425000000 { opp-hz = /bits/ 64 <425000000>; - opp-microvolt = <1150000>; + opp-microvolt = <1100000>; }; opp-510000000 { opp-hz = /bits/ 64 <510000000>; - opp-microvolt = <1150000>; + opp-microvolt = <1100000>; }; opp-637500000 { opp-hz = /bits/ 64 <637500000>; - opp-microvolt = <1150000>; + opp-microvolt = <1100000>; turbo-mode; }; };