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From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Doug Anderson <dianders@chromium.org>
Cc: Andy Gross <andy.gross@linaro.org>,
	David Brown <david.brown@linaro.org>,
	Sibi Sankar <sibis@codeaurora.org>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	devicetree@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 03/10] arm64: dts: sdm845: Introduce ADSP and CDSP PAS nodes
Date: Tue, 22 Jan 2019 17:09:30 -0800	[thread overview]
Message-ID: <20190123010930.GI31919@minitux> (raw)
In-Reply-To: <CAD=FV=Wsk3s2NbX4pR6v9-kK41edLF4hd7B_BanoFkAXyLBwyA@mail.gmail.com>

On Tue 22 Jan 16:40 PST 2019, Doug Anderson wrote:

> Hi,
> 
> On Tue, Jan 22, 2019 at 4:26 PM Bjorn Andersson
> <bjorn.andersson@linaro.org> wrote:
> > > > +               clocks = <&xo_board>;
> > > > +               clock-names = "xo";
> > >
> > > I've found that nearly all the places that refer to xo_board are wrong
> > > and should actually point to '<&rpmhcc RPMH_CXO_CLK>'.  Maybe yours
> > > should too?
> > >
> >
> > Yes, xo_board is a fake clock representing the 19.2MHz clock feeding the
> > cxo (or cxo2) pad of the SoC. So you're definitely right in that this
> > should be referencing the actual 19.2MHz clock.
> >
> > We've kept referring to this as xo_board, as we don't handle probe
> > deferral when gcc will probe earlier than rpmcc in the boot and for
> > other non-clock drivers the fear of actually hitting 0 on the refcounter
> > for this (you don't want to disable the cxo while running the system).
> 
> Note that, as defined in the device tree, "xo_board" is actually 38.4.
> IIUC that is not actually a fake/bogus clock but represents the actual
> crystal on the board.  There's a divide by 2 in the CPU though so most
> peripherals consider "xo" as 19.2.
> 

There's the 38.4MHz XO connected to the PMIC, but the signal going into
the CXO_IN pad of the SoC is supposed to come from LNBBCLK1 and be
19.2MHz.

> ...OK, confirmed.  The actual RF_XO_CLK pin on the board is truly
> connected to 38.4.
> 

And the three RF clocks from the PMIC are all ticking at 38.4MHz.


The "xo" I need here is the LNBBCLK1 (RPMH_CXO_CLK in clk-rpmh), for the
purpose of preventing the root clock to be turned off if apps goes to
suspend while the modem is booting, before it has had a chance to tell
RPM(h) that it needs it to be on.

Regards,
Bjorn

  reply	other threads:[~2019-01-23  1:09 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-22  5:51 [PATCH v3 00/10] Qualcomm AOSS QMP driver and modem dts Bjorn Andersson
2019-01-22  5:51 ` [PATCH v3 01/10] arm64: dts: qcom: sdm845: Update PIL region memory map Bjorn Andersson
2019-01-22 18:58   ` Stephen Boyd
2019-01-22 19:24     ` Bjorn Andersson
2019-01-22 23:10       ` Doug Anderson
2019-01-23  0:30         ` Bjorn Andersson
2019-01-22 23:16   ` Doug Anderson
2019-01-23  0:39     ` Bjorn Andersson
2019-01-25 17:40   ` Sibi Sankar
2019-01-22  5:51 ` [PATCH v3 02/10] arm64: dts: qcom: sdm845: Define rmtfs memory Bjorn Andersson
2019-01-22 23:26   ` Doug Anderson
2019-01-22 23:34     ` Brian Norris
2019-01-23  0:47     ` Bjorn Andersson
2019-01-22  5:51 ` [PATCH v3 03/10] arm64: dts: sdm845: Introduce ADSP and CDSP PAS nodes Bjorn Andersson
2019-01-22 23:46   ` Doug Anderson
2019-01-23  0:26     ` Bjorn Andersson
2019-01-23  0:40       ` Doug Anderson
2019-01-23  1:09         ` Bjorn Andersson [this message]
2019-01-23 23:24           ` Doug Anderson
2019-01-24  6:22             ` Stephen Boyd
2019-01-22  5:51 ` [PATCH v3 04/10] dt-bindings: soc: qcom: Add AOSS QMP binding Bjorn Andersson
2019-01-22 19:04   ` Stephen Boyd
2019-01-22 19:25     ` Bjorn Andersson
2019-01-22 19:28       ` Stephen Boyd
2019-01-22  5:51 ` [PATCH v3 05/10] soc: qcom: Add AOSS QMP communication driver Bjorn Andersson
2019-01-22  5:51 ` [PATCH v3 06/10] soc: qcom: Add AOSS QMP genpd provider Bjorn Andersson
2019-01-22  5:51 ` [PATCH v3 07/10] remoteproc: q6v5-mss: Vote for rpmh power domains Bjorn Andersson
2019-01-23  0:01   ` Doug Anderson
2019-01-22  5:51 ` [PATCH v3 08/10] remoteproc: q6v5-mss: Active powerdomain for SDM845 Bjorn Andersson
2019-01-22  5:51 ` [PATCH v3 09/10] arm64: dts: qcom: Add AOSS QMP node Bjorn Andersson
2019-01-22  5:51 ` [PATCH v3 10/10] arm64: dts: qcom: sdm845: Add Q6V5 MSS node Bjorn Andersson
2019-01-23  0:28   ` Doug Anderson
2019-01-23  1:10     ` Bjorn Andersson

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