linux-kernel - RE: [PATCH 4/6] video: s3c-fb: Take a runtime PM reference when unblanked

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Date:	Thu, 29 Dec 2011 08:54:47 +0900
From:	Jingoo Han <jg1.han@...sung.com>
To:	'Mark Brown' <broonie@...nsource.wolfsonmicro.com>,
	'Florian Tobias Schandinat' <FlorianSchandinat@....de>
Cc:	linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: RE: [PATCH 4/6] video: s3c-fb: Take a runtime PM reference when
 unblanked

> -----Original Message-----
> From: Mark Brown [mailto:broonie@...nsource.wolfsonmicro.com]
> Sent: Tuesday, December 27, 2011 11:16 PM
> To: Jingoo Han; Florian Tobias Schandinat
> Cc: linux-fbdev@...r.kernel.org; linux-kernel@...r.kernel.org; Mark Brown
> Subject: [PATCH 4/6] video: s3c-fb: Take a runtime PM reference when unblanked
> 
> When the framebuffer is unblanked hold a runtime PM reference. This
> prevents us powering down when userspace has left an image on the
> framebuffer and prepares the way for being able to power down the hardware
> when an application still has the device open.
> 
> Since we now hold a runtime PM reference whenever the display is unblanked
> there is no need for the runtime power management to disable and enable
> the display, and doing so would lead to runtime PM trying to recurse into
> itself when called from the blanking code, so split the runtime PM into
> separate functions which only deal with the clocks.  The PM core will
> runtime resume the device prior to system suspend.
> 
> Signed-off-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>

		Acked-by: Jingoo Han <jg1.han@...sung.com>

> ---
>  drivers/video/s3c-fb.c |   66 +++++++++++++++++++++++++++++++++++++++--------
>  1 files changed, 54 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/video/s3c-fb.c b/drivers/video/s3c-fb.c
> index 2e0eef0..688b9d8 100644
> --- a/drivers/video/s3c-fb.c
> +++ b/drivers/video/s3c-fb.c
> @@ -192,6 +192,7 @@ struct s3c_fb_vsync {
>   * @regs: The mapped hardware registers.
>   * @variant: Variant information for this hardware.
>   * @enabled: A bitmask of enabled hardware windows.
> + * @output_on: Flag if the physical output is enabled.
>   * @pdata: The platform configuration data passed with the device.
>   * @windows: The hardware windows that have been claimed.
>   * @irq_no: IRQ line number
> @@ -208,6 +209,7 @@ struct s3c_fb {
>  	struct s3c_fb_variant	 variant;
> 
>  	unsigned char		 enabled;
> +	bool			 output_on;
> 
>  	struct s3c_fb_platdata	*pdata;
>  	struct s3c_fb_win	*windows[S3C_FB_MAX_WIN];
> @@ -449,21 +451,28 @@ static void s3c_fb_enable(struct s3c_fb *sfb, int enable)
>  {
>  	u32 vidcon0 = readl(sfb->regs + VIDCON0);
> 
> -	if (enable)
> +	if (enable && !sfb->output_on)
> +		pm_runtime_get_sync(sfb->dev);
> +
> +	if (enable) {
>  		vidcon0 |= VIDCON0_ENVID | VIDCON0_ENVID_F;
> -	else {
> +	} else {
>  		/* see the note in the framebuffer datasheet about
>  		 * why you cannot take both of these bits down at the
>  		 * same time. */
> 
> -		if (!(vidcon0 & VIDCON0_ENVID))
> -			return;
> -
> -		vidcon0 |= VIDCON0_ENVID;
> -		vidcon0 &= ~VIDCON0_ENVID_F;
> +		if (vidcon0 & VIDCON0_ENVID) {
> +			vidcon0 |= VIDCON0_ENVID;
> +			vidcon0 &= ~VIDCON0_ENVID_F;
> +		}
>  	}
> 
>  	writel(vidcon0, sfb->regs + VIDCON0);
> +
> +	if (!enable && sfb->output_on)
> +		pm_runtime_put_sync(sfb->dev);
> +
> +	sfb->output_on = enable;
>  }
> 
>  /**
> @@ -1539,7 +1548,7 @@ static int __devexit s3c_fb_remove(struct platform_device *pdev)
>  	return 0;
>  }
> 
> -#ifdef CONFIG_PM
> +#ifdef CONFIG_PM_SLEEP
>  static int s3c_fb_suspend(struct device *dev)
>  {
>  	struct platform_device *pdev = to_platform_device(dev);
> @@ -1609,11 +1618,40 @@ static int s3c_fb_resume(struct device *dev)
> 
>  	return 0;
>  }
> -#else
> -#define s3c_fb_suspend NULL
> -#define s3c_fb_resume  NULL
>  #endif
> 
> +#ifdef CONFIG_PM_RUNTIME
> +static int s3c_fb_runtime_suspend(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct s3c_fb *sfb = platform_get_drvdata(pdev);
> +
> +	if (!sfb->variant.has_clksel)
> +		clk_disable(sfb->lcd_clk);
> +
> +	clk_disable(sfb->bus_clk);
> +
> +	return 0;
> +}
> +
> +static int s3c_fb_runtime_resume(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct s3c_fb *sfb = platform_get_drvdata(pdev);
> +	struct s3c_fb_platdata *pd = sfb->pdata;
> +
> +	clk_enable(sfb->bus_clk);
> +
> +	if (!sfb->variant.has_clksel)
> +		clk_enable(sfb->lcd_clk);
> +
> +	/* setup gpio and output polarity controls */
> +	pd->setup_gpio();
> +	writel(pd->vidcon1, sfb->regs + VIDCON1);
> +
> +	return 0;
> +}
> +#endif
> 
>  #define VALID_BPP124 (VALID_BPP(1) | VALID_BPP(2) | VALID_BPP(4))
>  #define VALID_BPP1248 (VALID_BPP124 | VALID_BPP(8))
> @@ -1936,7 +1974,11 @@ static struct platform_device_id s3c_fb_driver_ids[] = {
>  };
>  MODULE_DEVICE_TABLE(platform, s3c_fb_driver_ids);
> 
> -static UNIVERSAL_DEV_PM_OPS(s3cfb_pm_ops, s3c_fb_suspend, s3c_fb_resume, NULL);
> +static const struct dev_pm_ops s3cfb_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(s3c_fb_suspend, s3c_fb_resume)
> +	SET_RUNTIME_PM_OPS(s3c_fb_runtime_suspend, s3c_fb_runtime_resume,
> +			   NULL)
> +};
> 
>  static struct platform_driver s3c_fb_driver = {
>  	.probe		= s3c_fb_probe,
> --
> 1.7.7.3

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