Re: [PATCH v4.1] phylib: Add device reset GPIO support

From: Richard Leitner
Date: Mon Dec 04 2017 - 11:20:24 EST



On 12/04/2017 01:35 PM, Geert Uytterhoeven wrote:
> From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
>
> The PHY devices sometimes do have their reset signal (maybe even power
> supply?) tied to some GPIO and sometimes it also does happen that a boot
> loader does not leave it deasserted. So far this issue has been attacked
> from (as I believe) a wrong angle: by teaching the MAC driver to manipulate
> the GPIO in question; that solution, when applied to the device trees, led
> to adding the PHY reset GPIO properties to the MAC device node, with one
> exception: Cadence MACB driver which could handle the "reset-gpios" prop
> in a PHY device subnode. I believe that the correct approach is to teach
> the 'phylib' to get the MDIO device reset GPIO from the device tree node
> corresponding to this device -- which this patch is doing...
>
> Note that I had to modify the AT803x PHY driver as it would stop working
> otherwise -- it made use of the reset GPIO for its own purposes...
>
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
> Acked-by: Rob Herring <robh@xxxxxxxxxx>
> [geert: Propagate actual errors from fwnode_get_named_gpiod()]
> [geert: Avoid destroying initial setup]
> [geert: Consolidate GPIO descriptor acquiring code]
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> ---

Successfully tested this patch on a i.MX6SOLO based board containing a
LAN8710 PHY:

Tested-by: Richard Leitner <richard.leitner@xxxxxxxxxxx>