From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Lee Jones <lee.jones@linaro.org>
Cc: Chris Brandt <Chris.Brandt@renesas.com>,
Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@kernel.org>,
linux-spi <linux-spi@vger.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
linux-clk <linux-clk@vger.kernel.org>,
Mason Yang <masonccyang@mxic.com.tw>,
Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Subject: Re: [PATCH 2/6] ARM: dts: r7s72100: Add SPIBSC clocks
Date: Wed, 4 Dec 2019 10:03:02 +0100 [thread overview]
Message-ID: <CAMuHMdXC+=2nH51ASu0u3WUchjM5bC_bROgcYM-OrsM7OgZpbg@mail.gmail.com> (raw)
In-Reply-To: <20191204083821.GA3468@dell>
Hi Lee,
On Wed, Dec 4, 2019 at 9:38 AM Lee Jones <lee.jones@linaro.org> wrote:
> On Tue, 03 Dec 2019, Geert Uytterhoeven wrote:
> > On Tue, Dec 3, 2019 at 7:58 PM Chris Brandt <Chris.Brandt@renesas.com> wrote:
> > > On Tue, Dec 3, 2019, Geert Uytterhoeven wrote:
> > > > > + reg = <0x3fefa000 0x100>, <0x18000000
> > > > > + 0x4000000>;
> > > >
> > > > The second region conflicts with the XIP flash@18000000 in
> > > > arch/arm/boot/dts/r7s72100-gr-peach.dts.
> > > > Yes, I know it is the same device ;-)
> > >
> > > Is that just an FYI?? Or do you have some suggestion??
> >
> > Can the flash subnode be compatible with "mtd-rom", even if the parent node
> > is kept disabled?
> >
> > > > > + clock-critical = <4>; /* spibsc0 */
> > > >
> > > > Iff we go this clock-critical route, I think this should be specified in the
> > > > board-specific .dts instead of in the SoC-specific .dtsi.
> > >
> > > OK, that's fine. It makes more sense to be in the .dts because it's a board
> > > design decision. I will remove it from the patch.
> > >
> > > The one 'tricky' thing is that the <4> is the index into the number of clocks.
> > >
> > > So in the Renesas BSP where it includes the VDC5 LCD controllers,
> > >
> > > clock-output-names = "i2c0", "i2c1", "i2c2", "i2c3", "vdc50", "vdc51", "spibsc0", "spibsc1";
> > >
> > > the <4> needs to become a <6>.
> >
> > Unless you pass "clkidx" instead of "i" to of_clk_detect_critical() in [1],
> > and use "clock-critical = <R7S72100_CLK_SPIBSC0>" in DT?
> >
> > Unfortunately the exact semantics of clock-critical were never documented.
> > Lee?
>
> /**
> * of_clk_detect_critical() - set CLK_IS_CRITICAL flag from Device Tree
> * @np: Device node pointer associated with clock provider
> * @index: clock index
> * @flags: pointer to top-level framework flags
> *
> * Detects if the clock-critical property exists and, if so, sets the
> * corresponding CLK_IS_CRITICAL flag.
> *
> * Do not use this function. It exists only for legacy Device Tree
> * bindings, such as the one-clock-per-node style that are outdated.
> * Those bindings typically put all clock data into .dts and the Linux
> * driver has no clock data, thus making it impossible to set this flag
> * correctly from the driver. Only those drivers may call
> * of_clk_detect_critical from their setup functions.
> *
> * Return: error code or zero on success
> */
>
> If this meets the criteria, the API is pretty simple/self
> explanatory. What are you having trouble with?
What exactly is the "index" parameter? This value is matched against
the values of the "clock-critical" (array) property, but it is described
nowhere in the DT bindings.
stih407-clock.dtsi seems to assume this value is an index into the
clock-output-names array?
Can we use it as a value of "clock-indices" instead?
> > Thanks!
> >
> > [1] "[PATCH 1/6] clk: renesas: mstp: Add critical clock from device
> > tree support"
> > https://lore.kernel.org/linux-renesas-soc/20191203034519.5640-2-chris.brandt@renesas.com/
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2019-12-04 9:03 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-03 3:45 [PATCH 0/6] spi: Add Renesas SPIBSC controller Chris Brandt
2019-12-03 3:45 ` [PATCH 1/6] clk: renesas: mstp: Add critical clock from device tree support Chris Brandt
2019-12-03 18:32 ` Geert Uytterhoeven
2019-12-03 18:46 ` Chris Brandt
2019-12-03 18:51 ` Geert Uytterhoeven
2019-12-03 3:45 ` [PATCH 2/6] ARM: dts: r7s72100: Add SPIBSC clocks Chris Brandt
2019-12-03 18:42 ` Geert Uytterhoeven
2019-12-03 18:57 ` Chris Brandt
2019-12-03 19:12 ` Geert Uytterhoeven
2019-12-04 8:38 ` Lee Jones
2019-12-04 9:03 ` Geert Uytterhoeven [this message]
2019-12-04 9:47 ` Lee Jones
2019-12-04 11:00 ` Chris Brandt
2019-12-03 3:45 ` [PATCH 3/6] clk: renesas: r7s9210: Add SPIBSC clock Chris Brandt
2019-12-03 18:49 ` Geert Uytterhoeven
2019-12-03 19:09 ` Chris Brandt
2019-12-03 20:40 ` Geert Uytterhoeven
2019-12-04 3:09 ` Chris Brandt
2019-12-03 3:45 ` [PATCH 4/6] spi: Add SPIBSC driver Chris Brandt
2019-12-03 14:19 ` Mark Brown
2019-12-03 15:00 ` Chris Brandt
2019-12-03 18:29 ` Geert Uytterhoeven
2019-12-04 11:25 ` Mark Brown
2019-12-04 12:14 ` Geert Uytterhoeven
2019-12-04 15:51 ` Chris Brandt
2019-12-04 16:49 ` Mark Brown
2019-12-03 18:28 ` Geert Uytterhoeven
2019-12-04 11:18 ` Mark Brown
2019-12-04 22:12 ` Chris Brandt
2019-12-03 3:45 ` [PATCH 5/6] ARM: dts: r7s9210: Add SPIBSC Device support Chris Brandt
2019-12-03 18:59 ` Geert Uytterhoeven
2019-12-03 22:38 ` Chris Brandt
2019-12-04 7:57 ` Geert Uytterhoeven
2019-12-04 11:04 ` Chris Brandt
2019-12-03 3:45 ` [PATCH 6/6] dt-bindings: spi: Document Renesas SPIBSC bindings Chris Brandt
2019-12-03 9:14 ` Sergei Shtylyov
2019-12-03 13:27 ` Chris Brandt
2019-12-03 16:04 ` Sergei Shtylyov
2019-12-03 16:35 ` Chris Brandt
2019-12-03 18:57 ` Geert Uytterhoeven
2019-12-03 20:39 ` Geert Uytterhoeven
2019-12-04 2:54 ` Chris Brandt
2019-12-04 8:56 ` Geert Uytterhoeven
2019-12-04 13:31 ` Chris Brandt
2019-12-05 15:48 ` Geert Uytterhoeven
2019-12-05 16:00 ` Chris Brandt
2019-12-04 8:40 ` Geert Uytterhoeven
2019-12-03 22:33 ` Chris Brandt
2019-12-04 8:43 ` Geert Uytterhoeven
2019-12-04 11:19 ` Chris Brandt
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