Re: [Linux-kernel-mentees] [PATCH v1] [media] saa7134: use generic power management

[Vaibhav Gupta <vaibhavgupta40@gmail.com>]

On Mon, Jun 22, 2020 at 05:32:30PM +0530, Vaibhav Gupta wrote:
> With the support of generic PM callbacks, drivers no longer need to use
> legacy .suspend() and .resume() in which they had to maintain PCI states
> changes and device's power state themselves. The required operations are
> done by PCI core.
> 
> Compile-tested only.
> 
> Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
> ---
>  drivers/media/pci/saa7134/saa7134-core.c | 25 ++++++++----------------
>  1 file changed, 8 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/media/pci/saa7134/saa7134-core.c b/drivers/media/pci/saa7134/saa7134-core.c
> index e4623ed2f831..eb01109d4f98 100644
> --- a/drivers/media/pci/saa7134/saa7134-core.c
> +++ b/drivers/media/pci/saa7134/saa7134-core.c
> @@ -1370,10 +1370,8 @@ static void saa7134_finidev(struct pci_dev *pci_dev)
>  	kfree(dev);
>  }
>  
> -#ifdef CONFIG_PM
> -
>  /* resends a current buffer in queue after resume */
> -static int saa7134_buffer_requeue(struct saa7134_dev *dev,
> +static int __maybe_unused saa7134_buffer_requeue(struct saa7134_dev *dev,
>  				  struct saa7134_dmaqueue *q)
>  {
>  	struct saa7134_buf *buf, *next;
> @@ -1397,8 +1395,9 @@ static int saa7134_buffer_requeue(struct saa7134_dev *dev,
>  	return 0;
>  }
>  
> -static int saa7134_suspend(struct pci_dev *pci_dev , pm_message_t state)
> +static int __maybe_unused saa7134_suspend(struct device *dev_d)
>  {
> +	struct pci_dev *pci_dev = to_pci_dev(dev_d);
>  	struct v4l2_device *v4l2_dev = pci_get_drvdata(pci_dev);
>  	struct saa7134_dev *dev = container_of(v4l2_dev, struct saa7134_dev, v4l2_dev);
>  
> @@ -1428,21 +1427,15 @@ static int saa7134_suspend(struct pci_dev *pci_dev , pm_message_t state)
>  	if (dev->remote && dev->remote->dev->users)
>  		saa7134_ir_close(dev->remote->dev);
>  
> -	pci_save_state(pci_dev);
> -	pci_set_power_state(pci_dev, pci_choose_state(pci_dev, state));
> -
>  	return 0;
>  }
>  
> -static int saa7134_resume(struct pci_dev *pci_dev)
> +static int __maybe_unused saa7134_resume(struct device *dev_d)
>  {
> -	struct v4l2_device *v4l2_dev = pci_get_drvdata(pci_dev);
> +	struct v4l2_device *v4l2_dev = dev_get_drvdata(dev_d);
>  	struct saa7134_dev *dev = container_of(v4l2_dev, struct saa7134_dev, v4l2_dev);
>  	unsigned long flags;
>  
> -	pci_set_power_state(pci_dev, PCI_D0);
> -	pci_restore_state(pci_dev);
> -
>  	/* Do things that are done in saa7134_initdev ,
>  		except of initializing memory structures.*/
>  
> @@ -1490,7 +1483,6 @@ static int saa7134_resume(struct pci_dev *pci_dev)
>  
>  	return 0;
>  }
> -#endif
>  
>  /* ----------------------------------------------------------- */
>  
> @@ -1522,15 +1514,14 @@ EXPORT_SYMBOL(saa7134_ts_unregister);
>  
>  /* ----------------------------------------------------------- */
>  
> +static SIMPLE_DEV_PM_OPS(saa7134_pm_ops, saa7134_suspend, saa7134_resume);
> +
>  static struct pci_driver saa7134_pci_driver = {
>  	.name     = "saa7134",
>  	.id_table = saa7134_pci_tbl,
>  	.probe    = saa7134_initdev,
>  	.remove   = saa7134_finidev,
> -#ifdef CONFIG_PM
> -	.suspend  = saa7134_suspend,
> -	.resume   = saa7134_resume
> -#endif
> +	.driver.pm = &saa7134_pm_ops,
>  };
>  
>  static int __init saa7134_init(void)
> -- 
> 2.27.0
> 
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