[2/2] arm64: dts: marvell: clearfog-gt-8k: set SFP power limit
diff mbox series

Message ID a79d8f55eab7ed551ea4e052478b04a107e771c1.1558257666.git.baruch@tkos.co.il
State New, archived
Headers show
Series
  • [1/2] arm64: dts: marvell: mcbin: set SFP power limit
Related show

Commit Message

Baruch Siach May 19, 2019, 9:21 a.m. UTC
The Clearfog GT-8K board is capable of supplying power up to 2A to SFP
modules. Make that explicit in the device-tree. Without this property
current kernel does not allow SFP modules that require more than 1A.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
---
 arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts | 1 +
 1 file changed, 1 insertion(+)

Comments

Russell King - ARM Linux admin May 19, 2019, 6:20 p.m. UTC | #1
On Sun, May 19, 2019 at 12:21:06PM +0300, Baruch Siach wrote:
> The Clearfog GT-8K board is capable of supplying power up to 2A to SFP
> modules. Make that explicit in the device-tree. Without this property
> current kernel does not allow SFP modules that require more than 1A.

I do hope you're aware that current is not the same thing as power!
You say above "2A" which is a current, but the maximum power figure
below is "2W".  Given that modules are supplied with 3.3V, and
Power = Voltage x Current, this really doesn't work out!

Please can you correct both of your patches for accuracy in this
regard, thanks.

> 
> Signed-off-by: Baruch Siach <baruch@tkos.co.il>
> ---
>  arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts b/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
> index 9143aa13ceb1..f275d9420d5b 100644
> --- a/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
> +++ b/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
> @@ -63,6 +63,7 @@
>  		tx-disable-gpio = <&cp1_gpio1 29 GPIO_ACTIVE_HIGH>;
>  		pinctrl-names = "default";
>  		pinctrl-0 = <&cp0_sfp_present_pins &cp1_sfp_tx_disable_pins>;
> +		maximum-power-milliwatt = <2000>;
>  	};
>  
>  	leds {
> -- 
> 2.20.1
> 
>
Baruch Siach May 19, 2019, 6:25 p.m. UTC | #2
Hi Russell,

On Sun, May 19 2019, Russell King wrote:
> On Sun, May 19, 2019 at 12:21:06PM +0300, Baruch Siach wrote:
>> The Clearfog GT-8K board is capable of supplying power up to 2A to SFP
>> modules. Make that explicit in the device-tree. Without this property
>> current kernel does not allow SFP modules that require more than 1A.
>
> I do hope you're aware that current is not the same thing as power!
> You say above "2A" which is a current, but the maximum power figure
> below is "2W".  Given that modules are supplied with 3.3V, and
> Power = Voltage x Current, this really doesn't work out!
>
> Please can you correct both of your patches for accuracy in this
> regard, thanks.

My bad. I'll fix and resend.

Thanks for reviewing.

baruch

>> Signed-off-by: Baruch Siach <baruch@tkos.co.il>
>> ---
>>  arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts | 1 +
>>  1 file changed, 1 insertion(+)
>> 
>> diff --git a/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts b/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
>> index 9143aa13ceb1..f275d9420d5b 100644
>> --- a/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
>> +++ b/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
>> @@ -63,6 +63,7 @@
>>  		tx-disable-gpio = <&cp1_gpio1 29 GPIO_ACTIVE_HIGH>;
>>  		pinctrl-names = "default";
>>  		pinctrl-0 = <&cp0_sfp_present_pins &cp1_sfp_tx_disable_pins>;
>> +		maximum-power-milliwatt = <2000>;
>>  	};
>>  
>>  	leds {

Patch
diff mbox series

diff --git a/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts b/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
index 9143aa13ceb1..f275d9420d5b 100644
--- a/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
+++ b/arch/arm64/boot/dts/marvell/armada-8040-clearfog-gt-8k.dts
@@ -63,6 +63,7 @@ 
 		tx-disable-gpio = <&cp1_gpio1 29 GPIO_ACTIVE_HIGH>;
 		pinctrl-names = "default";
 		pinctrl-0 = <&cp0_sfp_present_pins &cp1_sfp_tx_disable_pins>;
+		maximum-power-milliwatt = <2000>;
 	};
 
 	leds {