linux-kernel - Re: [PATCH v2 2/7] can: m_can: Map WoL to device_set_wakeup

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Message-ID: <20240729-blue-cockle-of-vigor-7d7670-mkl@pengutronix.de>
Date: Mon, 29 Jul 2024 21:32:14 +0200
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Andrew Lunn <andrew@...n.ch>
Cc: Markus Schneider-Pargmann <msp@...libre.com>, 
	Chandrasekar Ramakrishnan <rcsekar@...sung.com>, Vincent Mailhol <mailhol.vincent@...adoo.fr>, 
	"David S . Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, Nishanth Menon <nm@...com>, 
	Vignesh Raghavendra <vigneshr@...com>, Tero Kristo <kristo@...nel.org>, 
	Martin Hundebøll <martin@...nix.com>, Christophe JAILLET <christophe.jaillet@...adoo.fr>, 
	Michal Kubiak <michal.kubiak@...el.com>, Vibhore Vardhan <vibhore@...com>, 
	Kevin Hilman <khilman@...libre.com>, Dhruva Gole <d-gole@...com>, Conor Dooley <conor@...nel.org>, 
	linux-can@...r.kernel.org, netdev@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 2/7] can: m_can: Map WoL to device_set_wakeup_enable

On 29.07.2024 21:27:04, Andrew Lunn wrote:
> On Mon, Jul 29, 2024 at 09:41:30AM +0200, Markus Schneider-Pargmann wrote:
> > In some devices the pins of the m_can module can act as a wakeup source.
> > This patch helps do that by connecting the PHY_WAKE WoL option to
> > device_set_wakeup_enable. By marking this device as being wakeup
> > enabled, this setting can be used by platform code to decide which
> > sleep or poweroff mode to use.
> > 
> > Also this prepares the driver for the next patch in which the pinctrl
> > settings are changed depending on the desired wakeup source.
> > 
> > Signed-off-by: Markus Schneider-Pargmann <msp@...libre.com>
> > ---
> >  drivers/net/can/m_can/m_can.c | 37 +++++++++++++++++++++++++++++++++++
> >  1 file changed, 37 insertions(+)
> > 
> > diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
> > index 81e05746d7d4..2e4ccf05e162 100644
> > --- a/drivers/net/can/m_can/m_can.c
> > +++ b/drivers/net/can/m_can/m_can.c
> > @@ -2182,6 +2182,36 @@ static int m_can_set_coalesce(struct net_device *dev,
> >  	return 0;
> >  }
> >  
> > +static void m_can_get_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
> > +{
> > +	struct m_can_classdev *cdev = netdev_priv(dev);
> > +
> > +	wol->supported = device_can_wakeup(cdev->dev) ? WAKE_PHY : 0;
> > +	wol->wolopts = device_may_wakeup(cdev->dev) ? WAKE_PHY : 0;
> > +}
> 
> It is nice to see Ethernet WoL mapped to CAN :-)
> 
> So will any activity on the CAN BUS wake the device? Or does it need
> to be addresses to this device?

Unless you have a special filtering transceiver, which is the CAN
equivalent of a PHY, CAN interfaces usually wake up on the first
message on the bus. That message is usually lost.

Note: The details of the m_can IP core might be different.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
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