[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <c6ea1360-9ca7-783e-0d0f-f5100fd8d024@collabora.com>
Date: Mon, 15 May 2023 13:47:49 +0200
From: AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>
To: Alexandre Mergnat <amergnat@...libre.com>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Wim Van Sebroeck <wim@...ux-watchdog.org>,
Guenter Roeck <linux@...ck-us.net>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Matthias Brugger <matthias.bgg@...il.com>,
Conor Dooley <conor+dt@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
linux-mediatek@...ts.infradead.org,
Kevin Hilman <khilman@...libre.com>
Subject: Re: [PATCH v7 08/11] arm64: dts: mediatek: add ethernet support for
mt8365-evk
Il 11/05/23 18:29, Alexandre Mergnat ha scritto:
> - Enable "vibr" and "vsim2" regulators to power the ethernet chip.
>
> Tested-by: Kevin Hilman <khilman@...libre.com>
> Signed-off-by: Alexandre Mergnat <amergnat@...libre.com>
> ---
> arch/arm64/boot/dts/mediatek/mt8365-evk.dts | 57 +++++++++++++++++++++++++++++
> 1 file changed, 57 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/mediatek/mt8365-evk.dts b/arch/arm64/boot/dts/mediatek/mt8365-evk.dts
> index 3a472f620ac0..cf81dace466a 100644
> --- a/arch/arm64/boot/dts/mediatek/mt8365-evk.dts
> +++ b/arch/arm64/boot/dts/mediatek/mt8365-evk.dts
> @@ -88,6 +88,28 @@ optee_reserved: optee@...00000 {
> };
> };
>
> +ðernet {
> + pinctrl-0 = <ðernet_pins>;
> + pinctrl-names = "default";
> + phy-handle = <ð_phy>;
> + phy-mode = "rmii";
> + /*
> + * Ethernet and HDMI (DSI0) are sharing pins.
> + * Only one can be enabled at a time and require the physical switch
> + * SW2101 to be set on LAN position
> + */
> + status = "disabled";
> +
> + mdio {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + eth_phy: ethernet-phy@0 {
> + reg = <0>;
> + };
> + };
> +};
> +
> &i2c0 {
> clock-frequency = <100000>;
> pinctrl-0 = <&i2c0_pins>;
> @@ -137,12 +159,47 @@ &mt6357_pmic {
> #interrupt-cells = <2>;
> };
>
> +/* Needed by analog switch (multiplexer), HDMI and ethernet */
What part of the ethernet HW needs this regulator?
> +&mt6357_vibr_reg {
> + regulator-always-on;
> +};
> +
> /* Needed by MSDC IP */
> &mt6357_vmc_reg {
> regulator-always-on;
> };
>
> +/* Needed by ethernet */
Same question for this one. If a device needs us to turn on a regulator in
order for it to be powered (read: if the supply is not fixed-on), setting
that supply as always-on is not beneficial for anyone, as eventually in a
power-off sleep/idle/whatever-pm state, this device (whole chip or IP) *will*
leak some amount of power.
If hardware engineers decided to connect a device to a supply that *can be*
shut down entirely there must be a reason, right? :-)
Regards,
Angelo
Powered by blists - more mailing lists