On 1 April 2013 13:53, Prabhakar Lad <prabhakar.csengg@xxxxxxxxx> wrote:
> On Mon, Apr 1, 2013 at 12:47 PM, Rajagopal Venkat
> <rajagopal.venkat@xxxxxxxxxx> wrote:
>> On 1 April 2013 12:06, Prabhakar lad <prabhakar.csengg@xxxxxxxxx> wrote:
>>> From: Lad, Prabhakar <prabhakar.csengg@xxxxxxxxx>
>>>
>>> Add pm_runtime support to the TI Davinci VPIF driver.
>>>
>>> Signed-off-by: Lad, Prabhakar <prabhakar.csengg@xxxxxxxxx>
>>> Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
>>> Cc: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>>> Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>>> Cc: Sakari Ailus <sakari.ailus@xxxxxx>
>>> Cc: Sekhar Nori <nsekhar@xxxxxx>
>>> ---
>>> Changes for v2:
>>> 1: Removed use of clk API as pointed by Laurent and Sekhar.
>>>
>>> drivers/media/platform/davinci/vpif.c | 24 +++++++-----------------
>>> 1 files changed, 7 insertions(+), 17 deletions(-)
>>>
>>> diff --git a/drivers/media/platform/davinci/vpif.c b/drivers/media/platform/davinci/vpif.c
>>> index 28638a8..599cabb 100644
>>> --- a/drivers/media/platform/davinci/vpif.c
>>> +++ b/drivers/media/platform/davinci/vpif.c
>>> @@ -23,8 +23,8 @@
>>> #include <linux/spinlock.h>
>>> #include <linux/kernel.h>
>>> #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 +44,6 @@ static struct resource *res;
>>> spinlock_t vpif_lock;
>>>
>>> void __iomem *vpif_base;
>>> -struct clk *vpif_clk;
>>>
>>> /**
>>> * ch_params: video standard configuration parameters for vpif
>>> @@ -439,19 +438,15 @@ static int vpif_probe(struct platform_device *pdev)
>>> goto fail;
>>> }
>>>
>>> - vpif_clk = clk_get(&pdev->dev, "vpif");
>>> - if (IS_ERR(vpif_clk)) {
>>> - status = PTR_ERR(vpif_clk);
>>> - goto clk_fail;
>>> - }
>>> - clk_prepare_enable(vpif_clk);
>>> + pm_runtime_enable(&pdev->dev);
>>> + pm_runtime_resume(&pdev->dev);
>>> +
>>> + pm_runtime_get(&pdev->dev);
>>
>> I don't see runtime-pm ops being registered. Can you explain how clock
>> prepare/unprepare is taken care by runtime-pm?
>>
> The pm_runtime API handles the clock management for you.
> For Davinci platform runtime PM support for clock management has
> been added (You can find it in arch/arm/mach-davinci/pm_domain.c)
> When runtime PM is enabled, the davinci runtime PM implementation will
> use the pm_clk layer to enable/disable clocks on demand.
I see. Thanks for the explanation.
>
> For more/detailed understanding you can go through the pm_runtime framework.
>
> Regards,
> --Prabhakar
--
Regards,
Rajagopal
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