dt-bindings: mdio: Clarify binding document

The described GPIO reset property is applicable to *all* child PHYs. If
we have one reset line per PHY present on the MDIO bus, these
automatically become properties of the child PHY nodes.

Finally, indicate how the RESET pulse width must be defined, which is
the maximum value of all individual PHYs RESET pulse widths determined
by reading their datasheets.

Fixes: 69226896ad ("mdio_bus: Issue GPIO RESET to PHYs.")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Florian Fainelli 2017-04-25 11:33:03 -07:00 committed by David S. Miller
parent 4629498336
commit 4c5e7a2c05
1 changed files with 8 additions and 4 deletions

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@ -3,13 +3,17 @@ Common MDIO bus properties.
These are generic properties that can apply to any MDIO bus.
Optional properties:
- reset-gpios: List of one or more GPIOs that control the RESET lines
of the PHYs on that MDIO bus.
- reset-delay-us: RESET pulse width in microseconds as per PHY datasheet.
- reset-gpios: One GPIO that control the RESET lines of all PHYs on that MDIO
bus.
- reset-delay-us: RESET pulse width in microseconds.
A list of child nodes, one per device on the bus is expected. These
should follow the generic phy.txt, or a device specific binding document.
The 'reset-delay-us' indicates the RESET signal pulse width in microseconds and
applies to all PHY devices. It must therefore be appropriately determined based
on all PHY requirements (maximum value of all per-PHY RESET pulse widths).
Example :
This example shows these optional properties, plus other properties
required for the TI Davinci MDIO driver.
@ -21,7 +25,7 @@ required for the TI Davinci MDIO driver.
#size-cells = <0>;
reset-gpios = <&gpio2 5 GPIO_ACTIVE_LOW>;
reset-delay-us = <2>; /* PHY datasheet states 1us min */
reset-delay-us = <2>;
ethphy0: ethernet-phy@1 {
reg = <1>;