linux-kernel - Re: [PATCH net-next v3 1/2] net: phy: replace PHY_HAS_INTERRUPT with a check for config_intr and ack

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Message-ID: <20181109203823.GY5259@lunn.ch>
Date:   Fri, 9 Nov 2018 21:38:23 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Heiner Kallweit <hkallweit1@...il.com>
Cc:     Florian Fainelli <f.fainelli@...il.com>,
        David Miller <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "maintainer:BROADCOM BCM63XX ARM ARCHITECTURE" 
        <bcm-kernel-feedback-list@...adcom.com>,
        Richard Cochran <richardcochran@...il.com>,
        Carlo Caione <carlo@...one.org>,
        Kevin Hilman <khilman@...libre.com>,
        open list <linux-kernel@...r.kernel.org>,
        "moderated list:BROADCOM BCM63XX ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        "open list:ARM/Amlogic Meson SoC support" 
        <linux-amlogic@...ts.infradead.org>
Subject: Re: [PATCH net-next v3 1/2] net: phy: replace PHY_HAS_INTERRUPT with
 a check for config_intr and ack_interrupt

On Fri, Nov 09, 2018 at 09:22:55PM +0100, Heiner Kallweit wrote:
> On 09.11.2018 21:13, Andrew Lunn wrote:
> > Hi Heiner
> > 
> >> +static bool phy_drv_supports_irq(struct phy_driver *phydrv)
> >> +{
> >> +	return phydrv->config_intr || phydrv->ack_interrupt;
> >> +}
> > 
> > Should this be && not || ? I thought both needed to be provided for
> > interrupts to work. 
> > 
> > 	   Andrew
> > 
> I've seen at least one driver which configures interrupts in
> config_init and doesn't define a config_intr callback
> (ack_interrupt callback is there)

> Intention of this check is not to ensure that the driver defines
> everything to make interrupts work. All it states:
> If at least one of the irq-related callbacks is defined, then
> we interpret this as indicator that the PHY supports interrupts.

I'm just wondering if that driver is broken if it enables interrupts
in config_init()? phylib deliberately enable/disable interrupts. If we
cannot do that, can we get an interrupt when we don't expect it? Can
we miss a state transition which would be reported when interrupts
would be re-enabled immediately triggering an interrupt?

Well, the current code does not seem to care if one is missing. So i
doubt this is making it more broken.

So,

Reviewed-by: Andrew Lunn <andrew@...n.ch>

    Andrew