netdev - RE: [PATCH V2 4/4] can: flexcan: add LPSR mode support

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Message-ID: <DB7PR04MB4618D604D85599B1B7E76810E65D0@DB7PR04MB4618.eurprd04.prod.outlook.com>
Date:   Wed, 4 Dec 2019 09:58:56 +0000
From:   Joakim Zhang <qiangqing.zhang@....com>
To:     Marc Kleine-Budde <mkl@...gutronix.de>,
        "sean@...nix.com" <sean@...nix.com>,
        "linux-can@...r.kernel.org" <linux-can@...r.kernel.org>
CC:     dl-linux-imx <linux-imx@....com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH V2 4/4] can: flexcan: add LPSR mode support


> -----Original Message-----
> From: Marc Kleine-Budde <mkl@...gutronix.de>
> Sent: 2019年12月4日 17:00
> To: Joakim Zhang <qiangqing.zhang@....com>; sean@...nix.com;
> linux-can@...r.kernel.org
> Cc: dl-linux-imx <linux-imx@....com>; netdev@...r.kernel.org
> Subject: Re: [PATCH V2 4/4] can: flexcan: add LPSR mode support
> 
> On 11/27/19 6:56 AM, Joakim Zhang wrote:
> > For i.MX7D LPSR mode, the controller will lost power and got the
> > configuration state lost after system resume back. (coming i.MX8QM/QXP
> > will also completely power off the domain, the controller state will
> > be lost and needs restore).
> > So we need to set pinctrl state again and re-start chip to do
> > re-configuration after resume.
> >
> > For wakeup case, it should not set pinctrl to sleep state by
> > pinctrl_pm_select_sleep_state.
> > For interface is not up before suspend case, we don't need
> > re-configure as it will be configured by user later by interface up.
> >
> > Signed-off-by: Joakim Zhang <qiangqing.zhang@....com>
> > ------
> > ChangeLog:
> > 	V1->V2: no change.
> > ---
> >  drivers/net/can/flexcan.c | 21 ++++++++++++++-------
> >  1 file changed, 14 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> > index d178146b3da5..d1509cffdd24 100644
> > --- a/drivers/net/can/flexcan.c
> > +++ b/drivers/net/can/flexcan.c
> > @@ -26,6 +26,7 @@
> >  #include <linux/platform_device.h>
> >  #include <linux/pm_runtime.h>
> >  #include <linux/regulator/consumer.h>
> > +#include <linux/pinctrl/consumer.h>
> >  #include <linux/regmap.h>
> >
> >  #define DRV_NAME			"flexcan"
> > @@ -1707,7 +1708,7 @@ static int __maybe_unused
> flexcan_suspend(struct
> > device *device)  {
> >  	struct net_device *dev = dev_get_drvdata(device);
> >  	struct flexcan_priv *priv = netdev_priv(dev);
> > -	int err = 0;
> > +	int err;
> >
> >  	if (netif_running(dev)) {
> >  		/* if wakeup is enabled, enter stop mode @@ -1719,25 +1720,27
> @@
> > static int __maybe_unused flexcan_suspend(struct device *device)
> >  			if (err)
> >  				return err;
> >  		} else {
> > -			err = flexcan_chip_disable(priv);
> > +			flexcan_chip_stop(dev);
> > +
> > +			err = pm_runtime_force_suspend(device);
> >  			if (err)
> >  				return err;
> >
> > -			err = pm_runtime_force_suspend(device);
> > +			pinctrl_pm_select_sleep_state(device);
> 
> Please add error handling for pinctrl_pm_select_sleep_state().
Got it.

> >  		}
> >  		netif_stop_queue(dev);
> >  		netif_device_detach(dev);
> >  	}
> >  	priv->can.state = CAN_STATE_SLEEPING;
> >
> > -	return err;
> > +	return 0;
> >  }
> >
> >  static int __maybe_unused flexcan_resume(struct device *device)  {
> >  	struct net_device *dev = dev_get_drvdata(device);
> >  	struct flexcan_priv *priv = netdev_priv(dev);
> > -	int err = 0;
> > +	int err;
> >
> >  	priv->can.state = CAN_STATE_ERROR_ACTIVE;
> >  	if (netif_running(dev)) {
> > @@ -1749,15 +1752,19 @@ static int __maybe_unused
> flexcan_resume(struct device *device)
> >  			if (err)
> >  				return err;
> >  		} else {
> > +			pinctrl_pm_select_default_state(device);
> 
> same here
Got it.

> > +
> >  			err = pm_runtime_force_resume(device);
> >  			if (err)
> >  				return err;
> >
> > -			err = flexcan_chip_enable(priv);
> > +			err = flexcan_chip_start(dev);
> > +			if (err)
> > +				return err;
> >  		}
> >  	}
> >
> > -	return err;
> > +	return 0;
> >  }
> >
> >  static int __maybe_unused flexcan_runtime_suspend(struct device
> > *device)
> >


Best Regards,
Joakim Zhang
> Marc
> 
> --
> Pengutronix e.K.                 | Marc Kleine-Budde           |
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