[v4,03/26] clk: sunxi-ng: Add check for maximum rate to NKM PLLs
diff mbox series

Message ID 20181113111633.20189-4-jagan@amarulasolutions.com
State New
Headers show
Series
  • drm/sun4i: Allwinner A64 MIPI-DSI support
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Commit Message

Jagan Teki Nov. 13, 2018, 11:16 a.m. UTC 
Some NKM PLLs, frequency can be set above PLL working range.

Add a constraint for maximum supported rate. This way, drivers can
specify which is maximum allowed rate for PLL.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
---
 drivers/clk/sunxi-ng/ccu_nkm.c | 3 +++
 drivers/clk/sunxi-ng/ccu_nkm.h | 1 +
 2 files changed, 4 insertions(+)

Comments

Maxime Ripard Nov. 13, 2018, 1:26 p.m. UTC | #1 
On Tue, Nov 13, 2018 at 04:46:10PM +0530, Jagan Teki wrote:
> Some NKM PLLs, frequency can be set above PLL working range.
> 
> Add a constraint for maximum supported rate. This way, drivers can
> specify which is maximum allowed rate for PLL.
> 
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> Acked-by: Stephen Boyd <sboyd@kernel.org>

As Vasily reported on a previous version, this should be squashed with
the patch 2.

> ---
>  drivers/clk/sunxi-ng/ccu_nkm.c | 3 +++
>  drivers/clk/sunxi-ng/ccu_nkm.h | 1 +
>  2 files changed, 4 insertions(+)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
> index 6b5ad990f802..b8b66cdd30bf 100644
> --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> @@ -128,6 +128,9 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
>  	if (rate < nkm->min_rate)
>  		return nkm->min_rate;
>  
> +	if (nkm->max_rate && rate > nkm->max_rate)
> +		return nkm->max_rate;
> +

I would expect the test to be the same for the minimum and maximum cases.

Maxime
Jagan Teki Nov. 15, 2018, 3:21 p.m. UTC | #2 
On Tue, Nov 13, 2018 at 6:57 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
>
> On Tue, Nov 13, 2018 at 04:46:10PM +0530, Jagan Teki wrote:
> > Some NKM PLLs, frequency can be set above PLL working range.
> >
> > Add a constraint for maximum supported rate. This way, drivers can
> > specify which is maximum allowed rate for PLL.
> >
> > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> > Acked-by: Stephen Boyd <sboyd@kernel.org>
>
> As Vasily reported on a previous version, this should be squashed with
> the patch 2.

Sorry, I missed it.

>
> > ---
> >  drivers/clk/sunxi-ng/ccu_nkm.c | 3 +++
> >  drivers/clk/sunxi-ng/ccu_nkm.h | 1 +
> >  2 files changed, 4 insertions(+)
> >
> > diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
> > index 6b5ad990f802..b8b66cdd30bf 100644
> > --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> > +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> > @@ -128,6 +128,9 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
> >       if (rate < nkm->min_rate)
> >               return nkm->min_rate;
> >
> > +     if (nkm->max_rate && rate > nkm->max_rate)
> > +             return nkm->max_rate;
> > +
>
> I would expect the test to be the same for the minimum and maximum cases.

I don't have proper use-case for max rate test, I do verify by using
higher the rate on dclock, but nor sure.  May be I can skip the
max_rate patch?

Apart from this, any idea about this issue where SUN4I_TCON0_DCLK_REG
will only work with div upto 6 on A64 DSI panels[1], did you find the
same issue on A33?

With parent rate 330MHz, the resulting tcon divider for 30MHz [2]
clock is 11 and for the same for 55MHz [3] clock is 6.

[3] https://paste.ubuntu.com/p/drvzfHFMtY/
[2] https://paste.ubuntu.com/p/hz29CTJY2J/
[1] https://elixir.bootlin.com/linux/v4.20-rc2/source/drivers/gpu/drm/sun4i/sun4i_dotclock.c#L125
Maxime Ripard Nov. 20, 2018, 10:55 a.m. UTC | #3 
On Thu, Nov 15, 2018 at 08:51:04PM +0530, Jagan Teki wrote:
> > >  drivers/clk/sunxi-ng/ccu_nkm.c | 3 +++
> > >  drivers/clk/sunxi-ng/ccu_nkm.h | 1 +
> > >  2 files changed, 4 insertions(+)
> > >
> > > diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
> > > index 6b5ad990f802..b8b66cdd30bf 100644
> > > --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> > > +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> > > @@ -128,6 +128,9 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
> > >       if (rate < nkm->min_rate)
> > >               return nkm->min_rate;
> > >
> > > +     if (nkm->max_rate && rate > nkm->max_rate)
> > > +             return nkm->max_rate;
> > > +
> >
> > I would expect the test to be the same for the minimum and maximum cases.
> 
> I don't have proper use-case for max rate test, I do verify by using
> higher the rate on dclock, but nor sure.  May be I can skip the
> max_rate patch?

So you're sending more patches that you haven't really tested?
Why are you sending them then?

> Apart from this, any idea about this issue where SUN4I_TCON0_DCLK_REG
> will only work with div upto 6 on A64 DSI panels[1], did you find the
> same issue on A33?

IIRC my panel was falling into the case where the divider was 4, so
I've not fallen into that case.

> With parent rate 330MHz, the resulting tcon divider for 30MHz [2]
> clock is 11 and for the same for 55MHz [3] clock is 6.

I'm not sure what the question is?

Maxime
Jagan Teki Nov. 20, 2018, 12:07 p.m. UTC | #4 
On Tue, Nov 20, 2018 at 4:26 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
>
> On Thu, Nov 15, 2018 at 08:51:04PM +0530, Jagan Teki wrote:
> > > >  drivers/clk/sunxi-ng/ccu_nkm.c | 3 +++
> > > >  drivers/clk/sunxi-ng/ccu_nkm.h | 1 +
> > > >  2 files changed, 4 insertions(+)
> > > >
> > > > diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
> > > > index 6b5ad990f802..b8b66cdd30bf 100644
> > > > --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> > > > +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> > > > @@ -128,6 +128,9 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
> > > >       if (rate < nkm->min_rate)
> > > >               return nkm->min_rate;
> > > >
> > > > +     if (nkm->max_rate && rate > nkm->max_rate)
> > > > +             return nkm->max_rate;
> > > > +
> > >
> > > I would expect the test to be the same for the minimum and maximum cases.
> >
> > I don't have proper use-case for max rate test, I do verify by using
> > higher the rate on dclock, but nor sure.  May be I can skip the
> > max_rate patch?
>
> So you're sending more patches that you haven't really tested?

I didn't understand this question.

> Why are you sending them then?

I think I've mentioned in the first version patch itself, since it's
common code and many other callers might have used for rate
alternative I did it how other ccu dividers does. I have not added
just as simple.
>
> > Apart from this, any idea about this issue where SUN4I_TCON0_DCLK_REG
> > will only work with div upto 6 on A64 DSI panels[1], did you find the
> > same issue on A33?
>
> IIRC my panel was falling into the case where the divider was 4, so
> I've not fallen into that case.

OK, thanks.

Patch
diff mbox series 

diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
index 6b5ad990f802..b8b66cdd30bf 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.c
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -128,6 +128,9 @@  static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
 	if (rate < nkm->min_rate)
 		return nkm->min_rate;
 
+	if (nkm->max_rate && rate > nkm->max_rate)
+		return nkm->max_rate;
+
 	ccu_nkm_find_best(*parent_rate, rate, &_nkm);
 
 	rate = *parent_rate * _nkm.n * _nkm.k / _nkm.m;
diff --git a/drivers/clk/sunxi-ng/ccu_nkm.h b/drivers/clk/sunxi-ng/ccu_nkm.h
index ff5bd00f429f..c82590481188 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.h
+++ b/drivers/clk/sunxi-ng/ccu_nkm.h
@@ -36,6 +36,7 @@  struct ccu_nkm {
 
 	unsigned int		fixed_post_div;
 	unsigned int		min_rate;
+	unsigned int		max_rate;
 
 	struct ccu_common	common;
 };