netdev - Re: PA Semi PWRficient Gigabit Ethernet doesn't work anymore since the first networking updates for the kernel 4.16

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Message-ID: <20180204171626.GE10544@lunn.ch>
Date:   Sun, 4 Feb 2018 18:16:26 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Christian Zigotzky <chzigotzky@...osoft.de>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>
Subject: Re: PA Semi PWRficient Gigabit Ethernet doesn't work anymore since
 the first networking updates for the kernel 4.16

On Sun, Feb 04, 2018 at 05:47:03PM +0100, Christian Zigotzky wrote:
> Hello,
> 
> The PA Semi PWRficient Gigabit Ethernet doesn't work anymore since the first
> networking updates [1] for the kernel 4.16.
> 
> Error messages:
> 
> [    0.634241] libphy: pasemi gpio mdio bus: probed
> [    0.634749] pasemi gpio mdio bus: Cannot register as MDIO bus, err -38

-38 is ENOSYS.

> --- a/drivers/net/phy/mdio_bus.c	2018-02-03 17:34:46.973045321 +0100
> +++ b/drivers/net/phy/mdio_bus.c	2018-02-04 11:03:14.909093360 +0100
> @@ -47,41 +47,11 @@
>  
>  #include "mdio-boardinfo.h"
>  
> -static int mdiobus_register_gpiod(struct mdio_device *mdiodev)
> -{
> -	struct gpio_desc *gpiod = NULL;
> -
> -	/* Deassert the optional reset signal */
> -	if (mdiodev->dev.of_node)
> -		gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
> -					       "reset-gpios", 0, GPIOD_OUT_LOW,
> -					       "PHY reset");

So i think you don't have GPIOLIB enabled. Hence you are hitting

http://elixir.free-electrons.com/linux/latest/source/include/linux/gpio/consumer.h#L470

static inline
struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
					 const char *propname, int index,
					 enum gpiod_flags dflags,
					 const char *label)
{
	return ERR_PTR(-ENOSYS);
}

So rather than just deleting all this code, breaking other platforms
that need this gpio, lets try a real fix. Please try this. If it
works, i will formally submit it.

   Andrew

>From a4210ba306948497d7360927c1e532eb903c58b2 Mon Sep 17 00:00:00 2001
From: Andrew Lunn <andrew@...n.ch>
Date: Sun, 4 Feb 2018 11:09:20 -0600
Subject: [PATCH] net: phy: Handle not having GPIO enabled in the kernel

If CONFIG_GPIOLIB is disabled, fwnode_get_named_gpiod() becomes a stub
function, which return -ENOSYS. Handle this in the same way as
-ENOENT, i.e. assume there is no GPIO used to reset the PHYs.

Reported-by: Christian Zigotzky <chzigotzky@...osoft.de>
Signed-off-by: Andrew Lunn <andrew@...n.ch>
---
 drivers/net/phy/mdio_bus.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 88272b3ac2e2..24b5511222c8 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -56,7 +56,8 @@ static int mdiobus_register_gpiod(struct mdio_device *mdiodev)
 		gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode,
 					       "reset-gpios", 0, GPIOD_OUT_LOW,
 					       "PHY reset");
-	if (PTR_ERR(gpiod) == -ENOENT)
+	if (PTR_ERR(gpiod) == -ENOENT ||
+	    PTR_ERR(gpiod) == -ENOSYS)
 		gpiod = NULL;
 	else if (IS_ERR(gpiod))
 		return PTR_ERR(gpiod);
-- 
2.15.1