During reset the VMMC regulator doesn't reach 0V and only drops to 1.8V, furthermore the pulse width is under 200us whereas the SD specification expect 1ms. For this 2 reasons being able to no reset at all the VMMC during warm reset and keep the current voltage is a good workaround. The TWL6030 allows this but needs to be aware of it and this configuration should also be shared with the bootloader. This is the purpose of this new property: ti,retain-on-reset Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx> --- .../devicetree/bindings/regulator/twl-regulator.txt | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/devicetree/bindings/regulator/twl-regulator.txt b/Documentation/devicetree/bindings/regulator/twl-regulator.txt index 74a91c4f8530..549f80436deb 100644 --- a/Documentation/devicetree/bindings/regulator/twl-regulator.txt +++ b/Documentation/devicetree/bindings/regulator/twl-regulator.txt @@ -71,3 +71,10 @@ Example: regulator-min-microvolt = <1000000>; regulator-max-microvolt = <3000000>; }; + +For twl6030 regulators/LDOs: + + - ti,retain-on-reset: Does not turn off the supplies during warm + reset. Could be needed for VMMC, as TWL6030 + reset sequence for this signal does not comply + with the SD specification. -- 2.20.1
