linux-kernel - Re: [PATCH v1 3/3] pwm: dwc: use to_pci

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Date: Sun, 28 Jan 2024 17:55:00 +0100
From: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Raag Jadav <raag.jadav@...el.com>, jarkko.nikula@...ux.intel.com, 
	mika.westerberg@...ux.intel.com, lakshmi.sowjanya.d@...el.com, linux-pwm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 3/3] pwm: dwc: use to_pci_dev() helper

Hello,

On Sun, Jan 28, 2024 at 04:46:48PM +0200, Andy Shevchenko wrote:
> On Mon, Jan 22, 2024 at 08:32:38AM +0530, Raag Jadav wrote:
> > Use to_pci_dev() helper to get pci device reference.
> 
> PCI
> 
> ...
> 
> >  static int dwc_pwm_suspend(struct device *dev)
> >  {
> > -	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
> > +	struct pci_dev *pdev = to_pci_dev(dev);
> >  	struct dwc_pwm *dwc = pci_get_drvdata(pdev);
> >  	int i;
> >  
> > @@ -120,7 +120,7 @@ static int dwc_pwm_suspend(struct device *dev)
> >  
> >  static int dwc_pwm_resume(struct device *dev)
> >  {
> > -	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
> > +	struct pci_dev *pdev = to_pci_dev(dev);
> >  	struct dwc_pwm *dwc = pci_get_drvdata(pdev);
> >  	int i;
> 
> I don't see how pdev is being used. That said, why dev_get_drvdata() is not
> suffice?

I would even consider using dev_get_drvdata() a nice cleanup given that
pci_get_drvdata() works because dwc_pwm_alloc() called dev_set_drvdata()
(and not pci_set_drvdata()).

Not so long ago (i.e. before commit a357d1493f0c ("pwm: dwc: Move memory
allocation to own function")) the dwc driver was pci only and used
pci_set_drvdata(). Then the upside of first converting the struct device
to a struct pci_dev was not to hard code knowledge about the
implementation of pci_[gs]et_drvdata().

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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