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Message-ID: <20151024071328.GQ10947@lukather>
Date: Sat, 24 Oct 2015 09:13:28 +0200
From: Maxime Ripard <maxime.ripard@...e-electrons.com>
To: Jean-Francois Moine <moinejf@...e.fr>
Cc: Jens Kuske <jenskuske@...il.com>, devicetree@...r.kernel.org,
Vishnu Patekar <vishnupatekar0510@...il.com>,
Emilio López <emilio@...pez.com.ar>,
Michael Turquette <mturquette@...libre.com>,
linux-sunxi@...glegroups.com, linux-kernel@...r.kernel.org,
Hans de Goede <hdegoede@...hat.com>,
Chen-Yu Tsai <wens@...e.org>, Rob Herring <robh+dt@...nel.org>,
Philipp Zabel <p.zabel@...gutronix.de>,
Linus Walleij <linus.walleij@...aro.org>,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 5/6] ARM: dts: sunxi: Add Allwinner H3 DTSI
On Fri, Oct 23, 2015 at 09:20:13PM +0200, Jean-Francois Moine wrote:
> On Fri, 23 Oct 2015 20:14:06 +0200
> Maxime Ripard <maxime.ripard@...e-electrons.com> wrote:
>
> > On Wed, Oct 21, 2015 at 06:20:27PM +0200, Jens Kuske wrote:
> > > + bus_gates: clk@...20060 {
> > > + #clock-cells = <1>;
> > > + compatible = "allwinner,sun8i-h3-bus-gates-clk";
> > > + reg = <0x01c20060 0x14>;
> > > + clock-indices = <5>, <6>, <8>,
> > > + <9>, <10>, <13>,
> > > + <14>, <17>, <18>,
> > > + <19>, <20>,
> > > + <21>, <23>,
> > > + <24>, <25>,
> > > + <26>, <27>,
> > > + <28>, <29>,
> > > + <30>, <31>, <32>,
> > > + <35>, <36>, <37>,
> > > + <40>, <41>, <43>,
> > > + <44>, <52>, <53>,
> > > + <54>, <64>,
> > > + <65>, <69>, <72>,
> > > + <76>, <77>, <78>,
> > > + <96>, <97>, <98>,
> > > + <112>, <113>,
> > > + <114>, <115>, <116>,
> > > + <128>, <135>;
> > > + clocks = <&ahb1>, <&ahb1>, <&ahb1>,
> > > + <&ahb1>, <&ahb1>, <&ahb1>,
> > > + <&ahb1>, <&ahb2>, <&ahb1>,
> > > + <&ahb1>, <&ahb1>,
> > > + <&ahb1>, <&ahb1>,
> > > + <&ahb1>, <&ahb1>,
> > > + <&ahb1>, <&ahb1>,
> > > + <&ahb1>, <&ahb2>,
> > > + <&ahb2>, <&ahb2>, <&ahb1>,
> > > + <&ahb1>, <&ahb1>, <&ahb1>,
> > > + <&ahb1>, <&ahb1>, <&ahb1>,
> > > + <&ahb1>, <&ahb1>, <&ahb1>,
> > > + <&ahb1>, <&apb1>,
> > > + <&apb1>, <&apb1>, <&apb1>,
> > > + <&apb1>, <&apb1>, <&apb1>,
> > > + <&apb2>, <&apb2>, <&apb2>,
> > > + <&apb2>, <&apb2>,
> > > + <&apb2>, <&apb2>, <&apb2>,
> > > + <&ahb1>, <&ahb1>;
> >
> > This is not really what I had in mind...
> >
> > This IP has 2 parents, and only two parents. The mapping between the
> > IPs should be done in the driver itself, not in the DT where it is
> > very error prone and barely readable.
> >
> > And note that I never have expected you to use clk-simple-gates
> > either. This is a complicated clock, unlike the other we've seen so
> > far, it definitely deserves a driver of its own.
>
> It seems that Allwinner puts the gate definitions anywhere in the array
> of registers, so, I think that the H3 scheme will not be the last
> complicated one,
Maybe, but that's the first one. It doesn't prevent us from reusing
the driver later if it happens.
> and if the parent clocks are in the code instead of in the DT, we
> will have more and more code to develop.
I never asked that either.
> An other way to describe the gates would be to add containers per parent
> (with still a small patch in the clk-simple-gates):
>
> bus_gates: clk@...20060 {
> #clock-cells = <1>;
> compatible = "allwinner,sun8i-h3-bus-gates-clk";
> reg = <0x01c20060 0x14>;
> ahb1_gates {
> clocks = <&ahb1>;
> clock-indices = <5>, <6>, <8>,
> <9>, <10>, <13>,
> <14>, <18>,
> <19>, <20>,
> ...;
> };
> clock-output-names = "ahb1_ce", "ahb1_dma", "ahb1_mmc0",
> "ahb1_mmc1", "ahb1_mmc2", "ahb1_nand",
> "ahb1_sdram", "ahb1_ts",
> "ahb1_hstimer", "ahb1_spi0",
> ...;
> };
> ahb2_gates {
> clocks = <&ahb2>;
> clock-indices = <17>, <29>,
> <30>, <31>, <32>,
> ...;
> clock-output-names = "ahb2_gmac", "ahb2_ohic1",
> "ahb2_ohic2", "ahb2_ohic3", "ahb1_ve",
> ...;
> };
> apb1_gates {
> ...
> };
> apb2_gates {
> ...
> };
> };
Or simply
bus_gates {
clocks = <&ahb1>, <&ahb2>;
clock-indices = <5>, <6>, <8>, ...
clock-output-names = "bus_ce", "bus_dma", "bus_mmc0"
};
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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