| Message ID | 20250608211452.72920-11-linux@fw-web.de |
|---|---|
| State | New |
| Headers | show |
| Series | further mt7988 devicetree work | expand |
Il 08/06/25 23:14, Frank Wunderlich ha scritto: > From: Frank Wunderlich <frank-w@public-files.de> > > Bananapi R4 has a green and a blue led which can be switched by gpio. > Green led is for running state so default on. > > Green led also shares pin with eeprom writeprotect where led off allows > writing to eeprom. This is extremely ugly from a hardware perspective and I'm sad to see such a thing here. Though, I don't see any other solution, so I can only give you an advice: don't ever write to the eeprom from the kernel. Things will eventually go south otherwise. I would also advise to add a read-only property to the eeprom node. Regardless (and sadly), Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Hi > Gesendet: Mittwoch, 11. Juni 2025 um 11:33 > Von: "AngeloGioacchino Del Regno" <angelogioacchino.delregno@collabora.com> > Betreff: Re: [PATCH v3 10/13] arm64: dts: mediatek: mt7988a-bpi-r4: add gpio leds > > Il 08/06/25 23:14, Frank Wunderlich ha scritto: > > From: Frank Wunderlich <frank-w@public-files.de> > > > > Bananapi R4 has a green and a blue led which can be switched by gpio. > > Green led is for running state so default on. > > > > Green led also shares pin with eeprom writeprotect where led off allows > > writing to eeprom. > > This is extremely ugly from a hardware perspective and I'm sad to see such > a thing here. i know, but cannot change this...found this out while testing the eeprom... where uboot allows the writing of eeprom currently without having this pin configured, linux does not and require green-led switch off. > Though, I don't see any other solution, so I can only give you an advice: > don't ever write to the eeprom from the kernel. Things will eventually go > south otherwise. > > I would also advise to add a read-only property to the eeprom node. the eeprom is empty from factory, but can be used to store e.g. mac-adress which are random by default. i tested a bit with tlv_eeprom command in uboot and some additional patches to archive this. imho green-led as running indicator on (=write-protect of eeprom) is a good solution => readonly by default, but allowing to write it if user is really sure :) > Regardless (and sadly), > > Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Thanks for your opinion and RB regards Frank
diff --git a/arch/arm64/boot/dts/mediatek/mt7988a-bananapi-bpi-r4.dtsi b/arch/arm64/boot/dts/mediatek/mt7988a-bananapi-bpi-r4.dtsi index 30affedf84d4..21eb91c8609f 100644 --- a/arch/arm64/boot/dts/mediatek/mt7988a-bananapi-bpi-r4.dtsi +++ b/arch/arm64/boot/dts/mediatek/mt7988a-bananapi-bpi-r4.dtsi @@ -21,6 +21,25 @@ fan: pwm-fan { status = "okay"; }; + gpio-leds { + compatible = "gpio-leds"; + + led_green: led-green { + function = LED_FUNCTION_STATUS; + color = <LED_COLOR_ID_GREEN>; + gpios = <&pio 79 GPIO_ACTIVE_HIGH>; + default-state = "on"; + }; + + led_blue: led-blue { + function = LED_FUNCTION_WPS; + color = <LED_COLOR_ID_BLUE>; + gpios = <&pio 63 GPIO_ACTIVE_HIGH>; + default-state = "off"; + }; + }; + + reg_1p8v: regulator-1p8v { compatible = "regulator-fixed"; regulator-name = "fixed-1.8V";