Re: [PATCH v3] drm/exynos: enable FIMD clocks

[Vikas Sajjan <vikas.sajjan@xxxxxxxxxx>]

Hi Mr Dae,

On 22 April 2013 11:19, Inki Dae <inki.dae@xxxxxxxxxxx> wrote:

Hi, Mr. Vikas

Please fix the below typos Viresh pointed out and my comments.

> -----Original Message-----
> From: Viresh Kumar [mailto:viresh.kumar@xxxxxxxxxx]
> Sent: Monday, April 01, 2013 5:51 PM
> To: Vikas Sajjan
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-samsung-soc@xxxxxxxxxxxxxxx;
> jy0922.shim@xxxxxxxxxxx; inki.dae@xxxxxxxxxxx; kgene.kim@xxxxxxxxxxx;
> linaro-kernel@xxxxxxxxxxxxxxxx; linux-media@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v3] drm/exynos: enable FIMD clocks
>
> On 1 April 2013 14:13, Vikas Sajjan <vikas.sajjan@xxxxxxxxxx> wrote:
> > While migrating to common clock framework (CCF), found that the FIMD
> clocks
>
> s/found/we found/
>
> > were pulled down by the CCF.
> > If CCF finds any clock(s) which has NOT been claimed by any of the
> > drivers, then such clock(s) are PULLed low by CCF.
> >
> > By calling clk_prepare_enable() for FIMD clocks fixes the issue.
>
> s/By calling/Calling/
>
> and
>
> s/the/this
>
> > this patch also replaces clk_disable() with clk_disable_unprepare()
>
> s/this/This
>
> > during exit.
>
> Sorry but your log doesn't say what you are doing. You are just adding
> relevant calls to clk_prepare/unprepare() before calling
> clk_enable/disable.
>

  I shall modify the commit message as below as suggested by tomaz figa,

  " Common Clock Framework introduced the need to prepare clocks before
enabling them, otherwise clk_enable() fails. This patch adds clk_prepare
calls to the driver. This patch also removes clk_disable() from fimd_remove() as it will be done by pm_runtime_put_sync".
 

> > Signed-off-by: Vikas Sajjan <vikas.sajjan@xxxxxxxxxx>
> > ---
> > Changes since v2:
> >         - moved clk_prepare_enable() and clk_disable_unprepare() from
> >         fimd_probe() to fimd_clock() as suggested by Inki Dae
> <inki.dae@xxxxxxxxxxx>
> > Changes since v1:
> >         - added error checking for clk_prepare_enable() and also
replaced
> >         clk_disable() with clk_disable_unprepare() during exit.
> > ---
> >  drivers/gpu/drm/exynos/exynos_drm_fimd.c |   14 +++++++-------
> >  1 file changed, 7 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> > index 9537761..f2400c8 100644
> > --- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> > +++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> > @@ -799,18 +799,18 @@ static int fimd_clock(struct fimd_context *ctx,
> bool enable)
> >         if (enable) {
> >                 int ret;
> >
> > -               ret = clk_enable(ctx->bus_clk);
> > +               ret = clk_prepare_enable(ctx->bus_clk);
> >                 if (ret < 0)
> >                         return ret;
> >
> > -               ret = clk_enable(ctx->lcd_clk);
> > +               ret = clk_prepare_enable(ctx->lcd_clk);
> >                 if  (ret < 0) {
> > -                       clk_disable(ctx->bus_clk);
> > +                       clk_disable_unprepare(ctx->bus_clk);
> >                         return ret;
> >                 }
> >         } else {
> > -               clk_disable(ctx->lcd_clk);
> > -               clk_disable(ctx->bus_clk);
> > +               clk_disable_unprepare(ctx->lcd_clk);
> > +               clk_disable_unprepare(ctx->bus_clk);
> >         }
> >
> >         return 0;
> > @@ -981,8 +981,8 @@ static int fimd_remove(struct platform_device *pdev)
> >         if (ctx->suspended)
> >                 goto out;
> >
> > -       clk_disable(ctx->lcd_clk);
> > -       clk_disable(ctx->bus_clk);
> > +       clk_disable_unprepare(ctx->lcd_clk);
> > +       clk_disable_unprepare(ctx->bus_clk);

Just remove the above codes. It seems that clk_disable(also
clk_disable_unprepare) isn't needed because it will be done by
pm_runtime_put_sync and please re-post it(probably patch v5??)

   So you mean I should work on v3 version, and keep  the clk_prepare_enable() code as is in fimd_clock() and just remove the clk_disable_unprepare() and also clk_disable() from fimd_remove(), right?

Viresh and Tomaz Figa, let me know if these changes are fine with you guys.

Thanks,
Inki Dae

>
> You are doing things at the right place but i have a suggestion. Are you
> doing
> anything in your clk_prepare() atleast for this device? Probably not.
>
> If not, then its better to call clk_prepare/unprepare only once at
> probe/remove
> and keep clk_enable/disable calls as is.
>
> --
> viresh

--
Thanks and Regards

 Vikas Sajjan

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