Re: [PATCH 2/3] netdev/of/phy: Add MDIO bus multiplexer support.
From: Grant Likely <hidden>
Date: 2011-09-15 00:51:02
Also in:
linux-devicetree, linux-mips
Possibly related (same subject, not in this thread)
- 2011-09-14 · Re: [PATCH 2/3] netdev/of/phy: Add MDIO bus multiplexer support. · Kumar Gala <hidden>
- 2011-09-13 · Re: [PATCH 2/3] netdev/of/phy: Add MDIO bus multiplexer support. · David Daney <hidden>
- 2011-09-13 · Re: [PATCH 2/3] netdev/of/phy: Add MDIO bus multiplexer support. · Kumar Gala <hidden>
- 2011-09-09 · Re: [PATCH 2/3] netdev/of/phy: Add MDIO bus multiplexer support. · Andy Fleming <hidden>
- 2011-08-31 · [PATCH 2/3] netdev/of/phy: Add MDIO bus multiplexer support. · David Daney <hidden>
On Aug 31, 2011 2:01 PM, "David Daney" [off-list ref] wrote:
This patch adds a somewhat generic framework for MDIO bus
multiplexers. It is modeled on the I2C multiplexer.
The multiplexer is needed if there are multiple PHYs with the same
address connected to the same MDIO bus adepter, or if there is
insufficient electrical drive capability for all the connected PHY
devices.
Conceptually it could look something like this:
------------------
| Control Signal |
--------+---------
|
--------------- --------+------
| MDIO MASTER |---| Multiplexer |
--------------- --+-------+----
| |
C C
h h
i i
l l
d d
| |
--------- A B ---------
| | | | | |
| PHY@1 +-------+ +---+ PHY@1 |
| | | | | |
--------- | | ---------
--------- | | ---------
| | | | | |
| PHY@2 +-------+ +---+ PHY@2 |
| | | |
--------- ---------
This framework configures the bus topology from device tree data. The
mechanics of switching the multiplexer is left to device specific
drivers.
The follow-on patch contains a multiplexer driven by GPIO lines.
Signed-off-by: David Daney <david.daney-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
Cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
Cc: "David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
---
Documentation/devicetree/bindings/net/mdio-mux.txt | 132 ++++++++++++++
drivers/net/phy/Kconfig | 8 +
drivers/net/phy/Makefile | 1 +
drivers/net/phy/mdio-mux.c | 182++++++++++++++++++++
quoted hunk
include/linux/mdio-mux.h | 18 ++ 5 files changed, 341 insertions(+), 0 deletions(-) create mode 100644 Documentation/devicetree/bindings/net/mdio-mux.txt create mode 100644 drivers/net/phy/mdio-mux.c create mode 100644 include/linux/mdio-mux.hdiff --git a/Documentation/devicetree/bindings/net/mdio-mux.txt
b/Documentation/devicetree/bindings/net/mdio-mux.txt
quoted hunk
new file mode 100644 index 0000000..a908312--- /dev/null +++ b/Documentation/devicetree/bindings/net/mdio-mux.txt@@ -0,0 +1,132 @@ +Common MDIO bus multiplexer/switch properties. + +An MDIO bus multiplexer/switch will have several child busses that are +numbered uniquely in a device dependent manner. The nodes for an MDIO +bus multiplexer/switch will have one child node for each child bus. + +Required properties: +- parent-bus : phandle to the parent MDIO bus.
As discussed, I like mdio-parent-bus.
+ +Optional properties: +- Other properties specific to the multiplexer/switch hardware. + +Required properties for child nodes: +- #address-cells = <1>; +- #size-cells = <0>; +- cell-index : The sub-bus number.
Use reg, not cell-index. That is what it is there for. And add the appropriate #address/size-cells in the parent. I've not reviewed the implementation, but with the changes. I'm okay with the binding. g.