| Message ID | 20201030172950.12767-3-dmurphy@ti.com |
|---|---|
| State | New |
| Headers | show |
| Series | [net-next,v3,1/4] ethtool: Add 10base-T1L link mode entries | expand |
On Fri, Oct 30, 2020 at 12:29:48PM -0500, Dan Murphy wrote: > Per the 802.3cg spec the 10base T1L can operate at 2 different > differential voltages 1v p2p and 2.4v p2p. The abiility of the PHY to > drive that output is dependent on the PHY's on board power supply. Hi Dan So this property is about the board being able to support the needed voltages? The PHY is not forced into 2.4v p2p, it just says the PHY can operate at 2.4v and the board will not melt, blow a fuse, etc? I actually think it is normal to specify the reverse. List the maximum that device can do because of board restrictions. e.g. - maximum-power-milliwatt : Maximum module power consumption Specifies the maximum power consumption allowable by a module in the slot, in milli-Watts. Presently, modules can be up to 1W, 1.5W or 2W. - max-link-speed: If present this property specifies PCI gen for link capability. Host drivers could add this as a strategy to avoid unnecessary operation for unsupported link speed, for instance, trying to do training for unsupported link speed, etc. Must be '4' for gen4, '3' for gen3, '2' for gen2, and '1' for gen1. Any other values are invalid. - max-microvolt : The maximum voltage value supplied to the haptic motor. [The unit of the voltage is a micro] So i think this property should be max-tx-rx-p2p = <1000>; to limit it to 1000mv p2p because of board PSU limitations, and it is free to do 22000mv is the property is not present. Andrew
Andrew On 10/30/20 2:56 PM, Andrew Lunn wrote: > On Fri, Oct 30, 2020 at 12:29:48PM -0500, Dan Murphy wrote: >> Per the 802.3cg spec the 10base T1L can operate at 2 different >> differential voltages 1v p2p and 2.4v p2p. The abiility of the PHY to >> drive that output is dependent on the PHY's on board power supply. > Hi Dan > > So this property is about the board being able to support the needed > voltages? The PHY is not forced into 2.4v p2p, it just says the PHY > can operate at 2.4v and the board will not melt, blow a fuse, etc? > > I actually think it is normal to specify the reverse. List the maximum > that device can do because of board restrictions. e.g. > > - maximum-power-milliwatt : Maximum module power consumption > Specifies the maximum power consumption allowable by a module in the > slot, in milli-Watts. Presently, modules can be up to 1W, 1.5W or 2W. > > - max-link-speed: > If present this property specifies PCI gen for link capability. Host > drivers could add this as a strategy to avoid unnecessary operation for > unsupported link speed, for instance, trying to do training for > unsupported link speed, etc. Must be '4' for gen4, '3' for gen3, '2' > for gen2, and '1' for gen1. Any other values are invalid. > > - max-microvolt : The maximum voltage value supplied to the haptic motor. > [The unit of the voltage is a micro] > > So i think this property should be > > max-tx-rx-p2p = <1000>; When I was re-writing the code I couldn't come up with a better property name but I like this one. I will implement it. Do you have any issue with the property being in the ethernet-phy.yaml? Dan
> Do you have any issue with the property being in the ethernet-phy.yaml?
It seems generic enough. Increasing the voltage increases the power
requirements, and maybe not all boards are capable of that.
Andrew
On Fri, Oct 30, 2020 at 08:56:55PM +0100, Andrew Lunn wrote: > On Fri, Oct 30, 2020 at 12:29:48PM -0500, Dan Murphy wrote: > > Per the 802.3cg spec the 10base T1L can operate at 2 different > > differential voltages 1v p2p and 2.4v p2p. The abiility of the PHY to > > drive that output is dependent on the PHY's on board power supply. > > Hi Dan > > So this property is about the board being able to support the needed > voltages? The PHY is not forced into 2.4v p2p, it just says the PHY > can operate at 2.4v and the board will not melt, blow a fuse, etc? > > I actually think it is normal to specify the reverse. List the maximum > that device can do because of board restrictions. e.g. > > - maximum-power-milliwatt : Maximum module power consumption > Specifies the maximum power consumption allowable by a module in the > slot, in milli-Watts. Presently, modules can be up to 1W, 1.5W or 2W. > > - max-link-speed: > If present this property specifies PCI gen for link capability. Host > drivers could add this as a strategy to avoid unnecessary operation for > unsupported link speed, for instance, trying to do training for > unsupported link speed, etc. Must be '4' for gen4, '3' for gen3, '2' > for gen2, and '1' for gen1. Any other values are invalid. > > - max-microvolt : The maximum voltage value supplied to the haptic motor. > [The unit of the voltage is a micro] > > So i think this property should be > > max-tx-rx-p2p = <1000>; > > to limit it to 1000mv p2p because of board PSU limitations, and it is > free to do 22000mv is the property is not present. '-microvolt' suffix please. > > Andrew >
diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml index 6dd72faebd89..5cad653e143b 100644 --- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml +++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml @@ -174,6 +174,11 @@ properties: PHY's that have configurable TX internal delays. If this property is present then the PHY applies the TX delay. + tx-rx-output-high: + type: boolean + description: | + Enable the 2.4v p2p differential output voltage for 10base-T1L PHYs. + required: - reg
Per the 802.3cg spec the 10base T1L can operate at 2 different differential voltages 1v p2p and 2.4v p2p. The abiility of the PHY to drive that output is dependent on the PHY's on board power supply. This common feature is applicable to all 10base T1L PHYs so this binding property belongs in a top level ethernet document. Signed-off-by: Dan Murphy <dmurphy@ti.com> --- Documentation/devicetree/bindings/net/ethernet-phy.yaml | 5 +++++ 1 file changed, 5 insertions(+)