The same GPIO line can be shared by multiple phys for the coma mode pin.
If that is the case then, all the other phys that share the same line
will failed to be probed because the access to the gpio line is not
non-exclusive.
Fix this by making access to the gpio line to be nonexclusive using flag
GPIOD_FLAGS_BIT_NONEXCLUSIVE. This allows all the other PHYs to be
probed.

Fixes: 738871b09250ee ("net: phy: micrel: add coma mode GPIO")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
 drivers/net/phy/micrel.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index e78d0bf69bc3..ea72ff64ad33 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -2878,7 +2878,8 @@ static int lan8814_release_coma_mode(struct phy_device *phydev)
 	struct gpio_desc *gpiod;
 
 	gpiod = devm_gpiod_get_optional(&phydev->mdio.dev, "coma-mode",
-					GPIOD_OUT_HIGH_OPEN_DRAIN);
+					GPIOD_OUT_HIGH_OPEN_DRAIN |
+					GPIOD_FLAGS_BIT_NONEXCLUSIVE);
 	if (IS_ERR(gpiod))
 		return PTR_ERR(gpiod);
 
-- 
2.33.0

On Wed, Aug 24, 2022 at 09:28:27PM +0200, Horatiu Vultur wrote:
> The same GPIO line can be shared by multiple phys for the coma mode pin.
> If that is the case then, all the other phys that share the same line
> will failed to be probed because the access to the gpio line is not
> non-exclusive.
> Fix this by making access to the gpio line to be nonexclusive using flag
> GPIOD_FLAGS_BIT_NONEXCLUSIVE. This allows all the other PHYs to be
> probed.
> 
> Fixes: 738871b09250ee ("net: phy: micrel: add coma mode GPIO")
> Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
> ---
>  drivers/net/phy/micrel.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
> index e78d0bf69bc3..ea72ff64ad33 100644
> --- a/drivers/net/phy/micrel.c
> +++ b/drivers/net/phy/micrel.c
> @@ -2878,7 +2878,8 @@ static int lan8814_release_coma_mode(struct phy_device *phydev)
>  	struct gpio_desc *gpiod;
>  
>  	gpiod = devm_gpiod_get_optional(&phydev->mdio.dev, "coma-mode",
> -					GPIOD_OUT_HIGH_OPEN_DRAIN);
> +					GPIOD_OUT_HIGH_OPEN_DRAIN |
> +					GPIOD_FLAGS_BIT_NONEXCLUSIVE);

I would suggest putting a comment here. You are assuming the driver
never gains a lan8814_take_coma_mode() when the PHY is put into
suspend, since it sounds like that will put all PHYs on the shared
GPIO into coma mode.

     Andrew

The 08/24/2022 21:47, Andrew Lunn wrote:

Hi Andrew,

> 
> On Wed, Aug 24, 2022 at 09:28:27PM +0200, Horatiu Vultur wrote:
> > The same GPIO line can be shared by multiple phys for the coma mode pin.
> > If that is the case then, all the other phys that share the same line
> > will failed to be probed because the access to the gpio line is not
> > non-exclusive.
> > Fix this by making access to the gpio line to be nonexclusive using flag
> > GPIOD_FLAGS_BIT_NONEXCLUSIVE. This allows all the other PHYs to be
> > probed.
> >
> > Fixes: 738871b09250ee ("net: phy: micrel: add coma mode GPIO")
> > Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
> > ---
> >  drivers/net/phy/micrel.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
> > index e78d0bf69bc3..ea72ff64ad33 100644
> > --- a/drivers/net/phy/micrel.c
> > +++ b/drivers/net/phy/micrel.c
> > @@ -2878,7 +2878,8 @@ static int lan8814_release_coma_mode(struct phy_device *phydev)
> >       struct gpio_desc *gpiod;
> >
> >       gpiod = devm_gpiod_get_optional(&phydev->mdio.dev, "coma-mode",
> > -                                     GPIOD_OUT_HIGH_OPEN_DRAIN);
> > +                                     GPIOD_OUT_HIGH_OPEN_DRAIN |
> > +                                     GPIOD_FLAGS_BIT_NONEXCLUSIVE);
> 
> I would suggest putting a comment here. You are assuming the driver
> never gains a lan8814_take_coma_mode() when the PHY is put into
> suspend, since it sounds like that will put all PHYs on the shared
> GPIO into coma mode.

That is correct.
I will add a comment in the next version.

> 
>      Andrew

-- 
/Horatiu