Re: [PATCH 4/5] clk: sunxi-ng: a64: Add constraints on PLL-VIDEO0's n/m ratio

From: "Jernej Škrabec" <jernej.skrabec@gmail.com>
To: Frank Oltmanns <frank@oltmanns.dev>
Cc: "Michael Turquette" <mturquette@baylibre.com>,
	"Stephen Boyd" <sboyd@kernel.org>, "Chen-Yu Tsai" <wens@csie.org>,
	"Samuel Holland" <samuel@sholland.org>,
	"Guido Günther" <agx@sigxcpu.org>,
	"Purism Kernel Team" <kernel@puri.sm>,
	"Ondrej Jirman" <megi@xff.cz>,
	"Neil Armstrong" <neil.armstrong@linaro.org>,
	"Jessica Zhang" <quic_jesszhan@quicinc.com>,
	"Sam Ravnborg" <sam@ravnborg.org>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"David Airlie" <airlied@gmail.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org,
	dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 4/5] clk: sunxi-ng: a64: Add constraints on PLL-VIDEO0's n/m ratio
Date: Wed, 20 Dec 2023 16:12:42 +0100	[thread overview]
Message-ID: <2174554.Mh6RI2rZIc@jernej-laptop> (raw)
In-Reply-To: <87il4t9wi1.fsf@oltmanns.dev>

Dne sreda, 20. december 2023 ob 08:09:28 CET je Frank Oltmanns napisal(a):
> 
> On 2023-12-19 at 17:54:19 +0100, Jernej Škrabec <jernej.skrabec@gmail.com> wrote:
> > Dne ponedeljek, 18. december 2023 ob 14:35:22 CET je Frank Oltmanns napisal(a):
> >> The Allwinner A64 manual lists the following constraint for the
> >> PLL-VIDEO0 clock: 8 <= N/M <= 25
> >>
> >> Use this constraint.
> >>
> >> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
> >> ---
> >>  drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 8 ++++++--
> >>  1 file changed, 6 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> >> index c034ac027d1c..75d839da446c 100644
> >> --- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> >> +++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> >> @@ -68,7 +68,8 @@ static SUNXI_CCU_NM_WITH_SDM_GATE_LOCK(pll_audio_base_clk, "pll-audio-base",
> >>  				       BIT(28),	/* lock */
> >>  				       CLK_SET_RATE_UNGATE);
> >>
> >> -static SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST(pll_video0_clk, "pll-video0",
> >> +static SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT_NM_RATIO(pll_video0_clk,
> >> +						"pll-video0",
> >>  						"osc24M", 0x010,
> >>  						192000000,	/* Minimum rate */
> >>  						1008000000,	/* Maximum rate */
> >> @@ -80,7 +81,10 @@ static SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST(pll_video0_clk, "pll-vid
> >>  						297000000,	/* frac rate 1 */
> >>  						BIT(31),	/* gate */
> >>  						BIT(28),	/* lock */
> >> -						CLK_SET_RATE_UNGATE);
> >> +						CLK_SET_RATE_UNGATE,
> >> +						CCU_FEATURE_FRACTIONAL |
> >> +						CCU_FEATURE_CLOSEST_RATE,
> >
> > Above flags are unrelated change, put them in new patch if needed.
> 
> You might notice that I am using a new macro for initializing the
> pll_video0_clk struct:
> New: SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT_NM_RATIO
> Old: SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST
> 
> Setting the two CCU_FEATURE flags is part of the old initialization
> macro.
> 
> I'll add SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_NM_RATIO_CLOSEST which
> hopefully resolves the confusion.

I'm in doubt if we need so many macros. How many users of these macro we'll have?
I see that R40 SoC would also need same ratio limits, but other that that, none?

Best regards,
Jernej

> 
> Thanks,
>   Frank
> 
> >
> > Best regards,
> > Jernej
> >
> >> +						8, 25);		/* min/max nm ratio */
> >>
> >>  static SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK(pll_ve_clk, "pll-ve",
> >>  					"osc24M", 0x018,
> >>
> >>
> 