mdio_bus: Issue GPIO RESET to PHYs.

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Some boards [1] leave the PHYs at an invalid state
during system power-up or reset thus causing unreliability
issues with the PHY which manifests as PHY not being detected
or link not functional. To fix this, these PHYs need to be RESET
via a GPIO connected to the PHY's RESET pin.

Some boards have a single GPIO controlling the PHY RESET pin of all
PHYs on the bus whereas some others have separate GPIOs controlling
individual PHY RESETs.

In both cases, the RESET de-assertion cannot be done in the PHY driver
as the PHY will not probe till its reset is de-asserted.
So do the RESET de-assertion in the MDIO bus driver.

[1] - am572x-idk, am571x-idk, a437x-idk

Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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Roger Quadros 2017-04-21 16:15:38 +03:00 • committed by David S. Miller

parent 15769ff8b6

commit 69226896ad

4 changed files with 94 additions and 0 deletions

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33

Documentation/devicetree/bindings/net/mdio.txt

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47

drivers/net/phy/mdio_bus.c

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7

drivers/of/of_mdio.c

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7

include/linux/phy.h

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