Re: [PATCH 1/9] clk: qcom: gcc-msm8998: Wire up gcc_mmss_gpll0 clock

[AngeloGioacchino Del Regno]

Il 14/01/21 23:44, Jeffrey Hugo ha scritto:
> On Thu, Jan 14, 2021 at 3:40 PM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@xxxxxxxxxxxxxx> wrote:
> > Il 14/01/21 23:33, Jeffrey Hugo ha scritto:
> > > On Thu, Jan 14, 2021 at 3:13 PM AngeloGioacchino Del Regno
> > > <angelogioacchino.delregno@xxxxxxxxxxxxxx> wrote:
> > > > Il 14/01/21 23:12, Jeffrey Hugo ha scritto:
> > > > > On Sat, Jan 9, 2021 at 6:47 AM AngeloGioacchino Del Regno
> > > > > <angelogioacchino.delregno@xxxxxxxxxxxxxx> wrote:
> > > > > > This clock enables the GPLL0 output to the multimedia subsystem
> > > > > > clock controller.
> > > > > >
> > > > > > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxxx>
> > > > >
> > > > > Any reason why you are not also adding the div_clk?
> > > >
> > > > Yes, just one: I haven't tested it... and my devices worked without.
> > > > Perhaps we can add it whenever we find out if something really needs it?
> > >
> > > I'm mildly surprised you need to turn on the gate to the PLL0 out, but
> > > not the div_out.  The div_out/div_clk is also fed into every RCG that
> > > exists in the MMCC.
> > >
> > > Per the frequency plan the following RCGs require it -
> > >
> > > cci
> > > cpp
> > > fd_core
> > > camss_gp[0-1]
> > > jpeg0
> > > mclk[0-3]
> > > csi[0-2]phytimer
> > > dp_gtc
> > > maxi
> > > axi
> > > ahb
> > >
> > > Also, I'm very interested in all things 8998, and would generally
> > > appreciate being added to the to: list.
> >
> > To be honest, I was surprised as well because.. yes, I know that these
> > RCGs seem to need it, but then their clock tables don't contain any
> > reference to the gpll0 divider, hence it's never getting used - and that
> > works great, for now.
> >
> > I am aware of the fact that the clocks that you've mentioned are using
> > the divider to reduce jitter, but I haven't done any camera test on my
> > devices yet: that's definitely in my plans and I really can't wait to do
> > that (as I successfully did for SDM630/660), but... we have more than
> > 100 patches in our trees.
> > We need to get upstream in the same working order as what we have here,
> > so that we don't diverge that much and our work is kept in a
> > maintainable state (avoiding to lose pieces around).
> >
> > I'm sure that I'll send a commit adding the gpll0 divider branch as soon
> > as I will start the camera work: I feel it, it's going to give me issues
> > without, in that field.
> >
> > By the way, noted. I'll make sure to add you in the to/cc for all of the
> > next series regarding 8998 that I'll send.
> >
> > Meanwhile, you may want to check out all the recent patches that I've
> > sent, as like 90% are MSM8998-centric... :))
>
> I noticed, and I'm excited to see additional work since I've had a
> lack of spare time, although I think you've monopolized my backlog  :)

I just... had some time... and passion about it :)))

P.S.: I'm not done yet!! :)