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* [PATCH 0/3] net: mdio-gpio enhancements
@ 2014-04-16  2:16 Guenter Roeck
  2014-04-16  2:16 ` [PATCH 1/3] net: mdio-gpio: Use devm_ functions where possible Guenter Roeck
                   ` (3 more replies)
  0 siblings, 4 replies; 13+ messages in thread
From: Guenter Roeck @ 2014-04-16  2:16 UTC (permalink / raw)
  To: Florian Fainelli; +Cc: Chris Healy, linux-kernel, netdev, Guenter Roeck

The following series of patches adds support for active-low gpio pins
as well as for systems with separate MDI and MDO pins to the mdio-gpio
driver.

A board using those features is based on a COM Express CPU board.
The COM Express standard supports GPIO pins on its connector,
with one caveat: The pins on the connector have fixed direction
and are hard configured either as input or output pins.
The COM Express Design Guide [1] provides additional details.

The hardware uses three of the GPO/GPI pins from the COM Express board
to drive an MDIO bus. Connectivity between GPI/GPO pins and the MDIO bus
is as follows.

GPI2 --------------------+------------ MDIO
                         |
            +--------+   |
GPO2 ---+---G        |   |
        |   |        |   |
       4.7k | 2N7002 D---+
	|   |        |
	+---S        |
	|   +--------+
       GND

GPO1 --------------------------------- MDC

To support this hardware, two extensions to the driver were necessary.

- Due to the FET in the MDO path (GPO2), the MDO signal is inverted.
  The driver therefore has to support active-low GPIO pins.

- The MDIO signal must be separated into MDI and MDO.

Those changes are implemented in patch 2/3 and 3/3.
Patch 1/3 simplifies the error path and thus the subsequent
patches.


[1] http://www.picmg.org/pdf/picmg_comdg_100.pdf

----------------------------------------------------------------
Guenter Roeck (3):
      net: mdio-gpio: Use devm_ functions where possible
      net: mdio-gpio: Add support for active low gpio pins
      net: mdio-gpio: Add support for separate MDI and MDO gpio pins

 drivers/net/phy/mdio-gpio.c |   68 ++++++++++++++++++++++++++++++-------------
 include/linux/mdio-gpio.h   |    5 ++++
 2 files changed, 52 insertions(+), 21 deletions(-)

^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2014-04-18 19:19 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-04-16  2:16 [PATCH 0/3] net: mdio-gpio enhancements Guenter Roeck
2014-04-16  2:16 ` [PATCH 1/3] net: mdio-gpio: Use devm_ functions where possible Guenter Roeck
2014-04-16  2:50   ` Chris Healy
2014-04-16  3:17     ` David Miller
2014-04-16 18:48   ` Chris Healy
2014-04-16 18:50     ` Chris Healy
2014-04-16 20:22       ` Guenter Roeck
2014-04-18 19:19   ` Sergei Shtylyov
2014-04-16  2:16 ` [PATCH 2/3] net: mdio-gpio: Add support for active low gpio pins Guenter Roeck
2014-04-16  2:44   ` Chris Healy
2014-04-16  2:16 ` [PATCH 3/3] net: mdio-gpio: Add support for separate MDI and MDO " Guenter Roeck
2014-04-16  2:45   ` Chris Healy
2014-04-16 19:10 ` [PATCH 0/3] net: mdio-gpio enhancements David Miller

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