Hi Sekhar, On Mon, Apr 1, 2013 at 11:33 AM, Sekhar Nori <nsek...@ti.com> wrote: > On 3/28/2013 3:50 PM, Prabhakar Lad wrote: >> Hi Laurent, >> >> On Thu, Mar 28, 2013 at 3:40 PM, Laurent Pinchart >> <laurent.pinch...@ideasonboard.com> wrote: >>> Hi Prabhakar, >>> >>> On Thursday 28 March 2013 15:36:11 Prabhakar Lad wrote: >>>> On Thu, Mar 28, 2013 at 2:39 PM, Laurent Pinchart wrote: >>>>> On Thursday 28 March 2013 14:20:32 Prabhakar lad wrote: >>>>>> From: Lad, Prabhakar <prabhakar.cse...@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.cse...@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 >>> >>> [snip] >>> >>>>>> @@ -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 ? >>>> >>>> The above check is to see if the clock is provided, once done >>>> we free it using clk_put(). >>> >>> In that case you shouldn't use devm_clk_get(), otherwise clk_put() will be >>> called again automatically at remove() time. >>> >> Yes agreed it should be clk_get() only. >> >>>>>> + 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 ? >>>> >>>> Yes pm runtime take care of enabling/disabling the clocks >>>> so that we don't have to do it in drivers. I believe clock >>>> handling is removed with this patch, with just devm_clk_get() remaining ;) >>> >>> When is the clk_get() call expected to fail ? If the clock is provided by >>> the >>> SoC and always available, can't the check be removed completely ? >>> >> Yes I agree with you it can be removed completely assuming the clock >> is always available from the Soc. >> But may be I need feedback from others Hans/Sekhar what do you suggest ? > > Unless you need the clk handle to get the clock rate or something, you > should simply rely on runtime PM calls to enable clocks for you and not > have any clk API call at all in your driver. > Thanks this helps!, I'll post a v2 fixing it.
Regards, --Prabhakar > Thanks, > Sekhar -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html