Re: [PATCH RFC 4/8] clk: sunxi-ng: a733: Add PLL clocks support

From: Enzo Adriano <enzo.adriano.code@gmail.com>
To: Junhui Liu <junhui.liu@pigmoral.tech>
Cc: Andre Przywara <andre.przywara@arm.com>,
	Brian Masney <bmasney@redhat.com>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>, Chen-Yu Tsai <wens@kernel.org>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Samuel Holland <samuel@sholland.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>,
	Richard Cochran <richardcochran@gmail.com>,
	linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-sunxi@lists.linux.dev, linux-riscv@lists.infradead.org,
	devicetree@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC 4/8] clk: sunxi-ng: a733: Add PLL clocks support
Date: Thu,  2 Jul 2026 13:10:20 -0400	[thread overview]
Message-ID: <20260702171020.836546-1-enzo.adriano.code@gmail.com> (raw)
In-Reply-To: <20260310-a733-clk-v1-4-36b4e9b24457@pigmoral.tech>

Hi Junhui,

Register check for the PLLs against the public A733 User Manual V0.92:
13 of the 14 PLL control registers match the manual's offsets
(PLL_DDR 0x0020 through PLL_DE 0x02E0, section 4.1.6.1 onwards).

The one exception is pll-ref at 0x0000: the manual's CCU register list
starts at 0x0020 (PLL_DDR), so the PLL_REF control register is not in
the public V0.92 document. It does match the vendor kernel's CCU
(SUN60IW2_PLL_REF_CTRL_REG 0x0000), so a short provenance note near the
definition might help future readers, same as for the other
vendor-sourced entries discussed in this thread. For what it's worth,
on a Radxa Cubie A7S (26 MHz DCXO) we can confirm at runtime that
pll-ref produces the normalized 24 MHz reference with the hosc-side
clocks reading 26 MHz, so the modeling demonstrably works on hardware.

Thanks,
Enzo