Re: [PATCH v4 3/8] dt-bindings: clock: Add Marvell PXA1908 clock bindings

From: Conor Dooley <conor@kernel.org>
To: "Duje Mihanović" <duje.mihanovic@skole.hr>
Cc: Conor Dooley <conor+dt@kernel.org>,
	Lubomir Rintel <lkundrak@v3.sk>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	Linus Walleij <linus.walleij@linaro.org>,
	Bartosz Golaszewski <brgl@bgdev.pl>,
	Andy Shevchenko <andy@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Kees Cook <keescook@chromium.org>,
	Tony Luck <tony.luck@intel.com>,
	"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
	linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-clk@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-hardening@vger.kernel.org,
	~postmarketos/upstreaming@lists.sr.ht,
	phone-devel@vger.kernel.org, afaerber@suse.de
Subject: Re: [PATCH v4 3/8] dt-bindings: clock: Add Marvell PXA1908 clock bindings
Date: Tue, 8 Aug 2023 11:46:23 +0100	[thread overview]
Message-ID: <20230808-quizzical-footwork-4846d6461f74@spud> (raw)
In-Reply-To: <2155917.irdbgypaU6@radijator>

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On Tue, Aug 08, 2023 at 12:41:22PM +0200, Duje Mihanović wrote:
> On Tuesday, August 8, 2023 9:49:49 AM CEST Conor Dooley wrote:
> > On Mon, Aug 07, 2023 at 05:42:37PM +0200, Duje Mihanović wrote:
> > > diff --git a/include/dt-bindings/clock/marvell,pxa1908.h
> > > b/include/dt-bindings/clock/marvell,pxa1908.h new file mode 100644
> > > index 000000000000..0c1f328bf534
> > > --- /dev/null
> > > +++ b/include/dt-bindings/clock/marvell,pxa1908.h
> > > +#define PXA1908_CLK_PLL4VCODIV3		38
> > > +#define PXA1908_MPMU_NR_CLKS		38
> > > 
> > > +#define PXA1908_CLK_TWSI3		18
> > > +#define PXA1908_APBC_NR_CLKS		50
> > > 
> > > +#define PXA1908_CLK_AICER		3
> > > +#define PXA1908_APBCP_NR_CLKS		50
> > > 
> > > +#define PXA1908_CLK_DVC_DFC_DEBUG	16
> > > +#define PXA1908_APMU_NR_CLKS		50
> > 
> > How are these "NR_CLKS" things helpful to the binding?
> 
> They are used by the clock driver when calling mmp_clk_init which then uses 
> that as the size of a struct clk array it allocates. In retrospect, 50 for 
> each block may be too much as from what I can tell by reading the 
> mmp_register_* functions (number of clocks + 1) for each block should be 
> enough, anything less than that causes a null pointer dereference sometime 
> during clock initialization.

I think you might have misread my question, I'm not really interested in
the implementation detail of the driver. If these are not used in
devicetree, remove them - otherwise they are being needlessly added to
the ABI.

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