linux-kernel - RE: [PATCH 04/11] i2c: imx-lpi2c: manage irq resource request/release in runtime pm

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Date:   Fri, 19 Mar 2021 10:12:12 +0000
From:   Aisheng Dong <aisheng.dong@....com>
To:     Clark Wang <xiaoning.wang@....com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>
CC:     "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "festevam@...il.com" <festevam@...il.com>,
        dl-linux-imx <linux-imx@....com>,
        "sumit.semwal@...aro.org" <sumit.semwal@...aro.org>,
        "christian.koenig@....com" <christian.koenig@....com>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 04/11] i2c: imx-lpi2c: manage irq resource request/release
 in runtime pm

> > > @@ -665,6 +659,14 @@ static int __maybe_unused
> > > lpi2c_runtime_resume(struct device *dev)
> > >  		dev_err(dev, "can't enable I2C ipg clock, ret=%d\n", ret);
> > >  	}
> > >
> > > +	ret = devm_request_irq(dev, lpi2c_imx->irq, lpi2c_imx_isr,
> >
> > I guess unnecessary to use devm in rpm
> 
> devm_request_irq() will use device resource management.
> Other resource like clk and struct space are all managed by devres.
> Maybe we can still use devm_ to let devres manage irq here?
> 

devm_xxx is usually used to auto free resources when probe fail,
driver unbound / device unregister and etc. Not for runtime pm.
I may prefer using request_irq/free_irq directly in runtime.

BTW, current lpi2c_imx_remove seems didn't ensure the device is
In runtime suspend state after removing.
If framework can't guarantee, the driver has to do it.
Anyway, that's another issue and need a separate patch.

Regards
Aisheng

> Thanks.
> 
> Best Regards,
> Clark Wang
> 
> 
> >
> > > +			       IRQF_NO_SUSPEND,
> > > +			       dev_name(dev), lpi2c_imx);
> > > +	if (ret) {
> > > +		dev_err(dev, "can't claim irq %d\n", lpi2c_imx->irq);
> > > +		return ret;
> > > +	}
> > > +
> > >  	return ret;
> > >  }
> > >
> > > --
> > > 2.25.1