On 08/07/2025 08:01, Zhangchao Zhang wrote: > Reset BT via BT_KILL_1V2_L hardware pin. > > On the M.2 standard hardware pin interface, the MTK chip > has a pin called BT_KILL_1V2_L or W_DISABLE#2, it uses > function-level device reset (FLDR) to reset Bluetooth. > When it is pulled low, it can external shut down the BT > function, it is defined as 5 on the MT7925 chip, and is > defined as 248 on the device tree pio controller. > > Signed-off-by: Zhangchao Zhang <ot_zhangchao.zhang@xxxxxxxxxxxx> > --- > .../bluetooth/mediatek,mt7925-bluetooth.yaml | 55 +++++++++++++++++++ > MAINTAINERS | 1 + > 2 files changed, 56 insertions(+) > create mode 100644 Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml > > diff --git a/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml > new file mode 100644 > index 000000000000..636b8b3d6a14 > --- /dev/null > +++ b/Documentation/devicetree/bindings/net/bluetooth/mediatek,mt7925-bluetooth.yaml > @@ -0,0 +1,55 @@ > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/net/bluetooth/mediatek,mt7925-bluetooth.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: Bluetooth mediatek use BT_KILL_1V2_L hardware pin to reset BT > + > +maintainers: > + - Sean Wang <sean.wang@xxxxxxxxxxxx> > + > +description: > + MT7925 chip uses the USB bus to communicate with the host. > + Two methods are used to reset Bluetooth. It provide hardware > + pin, when an exception occurs, resetting Bluetooth by hardware > + pin is more stable than resetting Bluetooth by software. If the > + corresponding pin is not found in dts, bluetooth can also be > + reset successfully. Don't describe DTS, but the hardware. > + > +allOf: > + - $ref: bluetooth-controller.yaml# > + > +properties: > + compatible: > + enum: > + - mediatek,mt7925-bluetooth > + > + "#gpio-cells": > + const: 2 You did not say this is a GPIO controller. > + > + reset-gpios: > + maxItems: 1 > + description: > + Default high level, this pin can external shut down the BT function How defaults matter? > + when this pin is pull low, at the same time, USB interface will be also > + disabled. When this function is not required, external pull high is not So active low? > + required. After 200ms, it is pulled high to 3.3v and the next probe is > + performed. On typical M.2 key E modules this is the W_DISABLE2# pin. So that's part of PCI slot? Sorry, but this does not fit here at all. Best regards, Krzysztof
