From: David S. Miller <davem@davemloft.net>
Date: Wed, 16 Apr 2014 19:10:00 +0000 (-0400)
Subject: Merge branch 'mdio-gpio'
X-Git-Tag: v4.14-rc1~7638^2~10
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c3206e6fc0e1459c56a42e0eb5a3f559e6ca43f1;p=platform%2Fkernel%2Flinux-rpi.git

Merge branch 'mdio-gpio'

Guenter Roeck says:

====================
net: mdio-gpio enhancements

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
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
---

c3206e6fc0e1459c56a42e0eb5a3f559e6ca43f1