Re: [PATCH] davinci: vpif: add pm_runtime support

Laurent Pinchart
2013-03-28T09:08:38Z

Hi Prabhakar,

Thanks for the patch.

On Thursday 28 March 2013 14:20:32 Prabhakar lad wrote:
> From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
>
> Add pm_runtime support to the TI Davinci VPIF driver.
> Along side this patch replaces clk_get() with devm_clk_get()
> to simplify the error handling.
>
> Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
> ---
> drivers/media/platform/davinci/vpif.c | 21 +++++++++++----------
> 1 files changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/media/platform/davinci/vpif.c
> b/drivers/media/platform/davinci/vpif.c index 28638a8..7d14625 100644
> --- a/drivers/media/platform/davinci/vpif.c
> +++ b/drivers/media/platform/davinci/vpif.c
> @@ -25,6 +25,7 @@
> #include <linux/io.h>
> #include <linux/clk.h>
> #include <linux/err.h>
> +#include <linux/pm_runtime.h>
> #include <linux/v4l2-dv-timings.h>
>
> #include <mach/hardware.h>
> @@ -44,7 +45,6 @@ static struct resource *res;
> spinlock_t vpif_lock;
>
> void __iomem *vpif_base;
> -struct clk *vpif_clk;
>
> /**
> * ch_params: video standard configuration parameters for vpif
> @@ -421,6 +421,7 @@ EXPORT_SYMBOL(vpif_channel_getfid);
>
> static int vpif_probe(struct platform_device *pdev)
> {
> + struct clk *vpif_clk;
> int status = 0;
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> @@ -439,12 +440,17 @@ static int vpif_probe(struct platform_device *pdev)
> goto fail;
> }
>
> - vpif_clk = clk_get(&pdev->dev, "vpif");
> + vpif_clk = devm_clk_get(&pdev->dev, "vpif");
> if (IS_ERR(vpif_clk)) {
> status = PTR_ERR(vpif_clk);
> goto clk_fail;
> }
> - clk_prepare_enable(vpif_clk);
> + clk_put(vpif_clk);

Why do you need to call clk_put() here ?

> + pm_runtime_enable(&pdev->dev);
> + pm_runtime_resume(&pdev->dev);
> +
> + pm_runtime_get(&pdev->dev);

Does runtime PM automatically handle your clock ? If so can't you remove clock
handling from the driver completely ?

> spin_lock_init(&vpif_lock);
> dev_info(&pdev->dev, "vpif probe success\n");
> @@ -459,11 +465,6 @@ fail:
>
> static int vpif_remove(struct platform_device *pdev)
> {
> - if (vpif_clk) {
> - clk_disable_unprepare(vpif_clk);
> - clk_put(vpif_clk);
> - }
> -
> iounmap(vpif_base);
> release_mem_region(res->start, res_len);
> return 0;
> @@ -472,13 +473,13 @@ static int vpif_remove(struct platform_device *pdev)
> #ifdef CONFIG_PM
> static int vpif_suspend(struct device *dev)
> {
> - clk_disable_unprepare(vpif_clk);
> + pm_runtime_put(dev);
> return 0;
> }
>
> static int vpif_resume(struct device *dev)
> {
> - clk_prepare_enable(vpif_clk);
> + pm_runtime_get(dev);
> return 0;
> }
--
Regards,

Laurent Pinchart