linux-kernel - Re: [PATCH net-next v1 4/4] net: phy: mxl-gpy: disable interrupts on GPY215 by default

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Message-ID: <Y4pHCQrDbXXmOT+A@lunn.ch>
Date:   Fri, 2 Dec 2022 19:42:17 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Michael Walle <michael@...le.cc>
Cc:     Xu Liang <lxu@...linear.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH net-next v1 4/4] net: phy: mxl-gpy: disable interrupts on
 GPY215 by default

On Fri, Dec 02, 2022 at 04:12:04PM +0100, Michael Walle wrote:
> The interrupts on the GPY215B and GPY215C are broken and the only viable
> fix is to disable them altogether. There is still the possibilty to
> opt-in via the device tree.
> 
> Signed-off-by: Michael Walle <michael@...le.cc>
> ---
>  drivers/net/phy/mxl-gpy.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/phy/mxl-gpy.c b/drivers/net/phy/mxl-gpy.c
> index 20e610dda891..edb8cd8313b0 100644
> --- a/drivers/net/phy/mxl-gpy.c
> +++ b/drivers/net/phy/mxl-gpy.c
> @@ -12,6 +12,7 @@
>  #include <linux/mutex.h>
>  #include <linux/phy.h>
>  #include <linux/polynomial.h>
> +#include <linux/property.h>
>  #include <linux/netdevice.h>
>  
>  /* PHY ID */
> @@ -290,6 +291,10 @@ static int gpy_probe(struct phy_device *phydev)
>  	phydev->priv = priv;
>  	mutex_init(&priv->mbox_lock);
>  
> +	if (gpy_has_broken_mdint(phydev) &&
> +	    !device_property_present(dev, "maxlinear,use-broken-interrupts"))
> +		phydev->irq = PHY_POLL;
> +

I'm not sure of ordering here. It could be phydev->irq is set after
probe. The IRQ is requested as part of phy_connect_direct(), which is
much later.

I think a better place for this test is in gpy_config_intr(), return
-EOPNOTSUPP. phy_enable_interrupts() failing should then cause
phy_request_interrupt() to use polling.

	Andrew