net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
* Microsemi - vsc8531 Giga bit ethernet phy
|
|
|
|
|
|
|
|
|
|
Optional properties:
|
2016-10-12 13:47:51 +00:00
|
|
|
- vsc8531,vddmac : The vddmac in mV. Allowed values is listed
|
|
|
|
|
in the first row of Table 1 (below).
|
|
|
|
|
This property is only used in combination
|
|
|
|
|
with the 'edge-slowdown' property.
|
|
|
|
|
Default value is 3300.
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
- vsc8531,edge-slowdown : % the edge should be slowed down relative to
|
2016-10-12 13:47:51 +00:00
|
|
|
the fastest possible edge time.
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
Edge rate sets the drive strength of the MAC
|
2016-10-12 13:47:51 +00:00
|
|
|
interface output signals. Changing the
|
|
|
|
|
drive strength will affect the edge rate of
|
|
|
|
|
the output signal. The goal of this setting
|
|
|
|
|
is to help reduce electrical emission (EMI)
|
|
|
|
|
by being able to reprogram drive strength
|
|
|
|
|
and in effect slow down the edge rate if
|
|
|
|
|
desired.
|
|
|
|
|
To adjust the edge-slowdown, the 'vddmac'
|
|
|
|
|
must be specified. Table 1 lists the
|
|
|
|
|
supported edge-slowdown values for a given
|
|
|
|
|
'vddmac'.
|
|
|
|
|
Default value is 0%.
|
|
|
|
|
Ref: Table:1 - Edge rate change (below).
|
2017-02-07 13:40:26 +00:00
|
|
|
- vsc8531,led-0-mode : LED mode. Specify how the LED[0] should behave.
|
|
|
|
|
Allowed values are define in
|
|
|
|
|
"include/dt-bindings/net/mscc-phy-vsc8531.h".
|
|
|
|
|
Default value is VSC8531_LINK_1000_ACTIVITY (1).
|
|
|
|
|
- vsc8531,led-1-mode : LED mode. Specify how the LED[1] should behave.
|
|
|
|
|
Allowed values are define in
|
|
|
|
|
"include/dt-bindings/net/mscc-phy-vsc8531.h".
|
|
|
|
|
Default value is VSC8531_LINK_100_ACTIVITY (2).
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
|
|
|
|
|
Table: 1 - Edge rate change
|
|
|
|
|
----------------------------------------------------------------|
|
|
|
|
|
| Edge Rate Change (VDDMAC) |
|
|
|
|
|
| |
|
|
|
|
|
| 3300 mV 2500 mV 1800 mV 1500 mV |
|
|
|
|
|
|---------------------------------------------------------------|
|
2016-10-12 13:47:51 +00:00
|
|
|
| 0% 0% 0% 0% |
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
| (Fastest) (recommended) (recommended) |
|
|
|
|
|
|---------------------------------------------------------------|
|
2016-10-12 13:47:51 +00:00
|
|
|
| 2% 3% 5% 6% |
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
|---------------------------------------------------------------|
|
2016-10-12 13:47:51 +00:00
|
|
|
| 4% 6% 9% 14% |
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
|---------------------------------------------------------------|
|
2016-10-12 13:47:51 +00:00
|
|
|
| 7% 10% 16% 21% |
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
|(recommended) (recommended) |
|
|
|
|
|
|---------------------------------------------------------------|
|
2016-10-12 13:47:51 +00:00
|
|
|
| 10% 14% 23% 29% |
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
|---------------------------------------------------------------|
|
2016-10-12 13:47:51 +00:00
|
|
|
| 17% 23% 35% 42% |
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
|---------------------------------------------------------------|
|
2016-10-12 13:47:51 +00:00
|
|
|
| 29% 37% 52% 58% |
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
|---------------------------------------------------------------|
|
2016-10-12 13:47:51 +00:00
|
|
|
| 53% 63% 76% 77% |
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
| (slowest) |
|
|
|
|
|
|---------------------------------------------------------------|
|
|
|
|
|
|
|
|
|
|
Example:
|
|
|
|
|
|
|
|
|
|
vsc8531_0: ethernet-phy@0 {
|
|
|
|
|
compatible = "ethernet-phy-id0007.0570";
|
|
|
|
|
vsc8531,vddmac = <3300>;
|
2016-10-12 13:47:51 +00:00
|
|
|
vsc8531,edge-slowdown = <7>;
|
2017-02-07 13:40:26 +00:00
|
|
|
vsc8531,led-0-mode = <LINK_1000_ACTIVITY>;
|
|
|
|
|
vsc8531,led-1-mode = <LINK_100_ACTIVITY>;
|
net: phy: Add Edge-rate driver for Microsemi PHYs.
Edge-rate:
As system and networking speeds increase, a signal's output transition,
also know as the edge rate or slew rate (V/ns), takes on greater importance
because high-speed signals come with a price. That price is an assortment of
interference problems like ringing on the line, signal overshoot and
undershoot, extended signal settling times, crosstalk noise, transmission
line reflections, false signal detection by the receiving device and
electromagnetic interference (EMI) -- all of which can negate the potential
gains designers are seeking when they try to increase system speeds through
the use of higher performance logic devices. The fact is, faster signaling
edge rates can cause a higher level of electrical noise or other type of
interference that can actually lead to slower line speeds and lower maximum
system frequencies. This parameter allow the board designers to change the
driving strange, and thereby change the EMI behavioral.
Edge-rate parameters (vddmac, edge-slowdown) get from Device Tree.
Tested on Beaglebone Black with VSC 8531 PHY.
Signed-off-by: Raju Lakkaraju <Raju.Lakkaraju@microsemi.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-03 07:23:13 +00:00
|
|
|
};
|
