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From: Jernej =?utf-8?B?xaBrcmFiZWM=?= <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 =?ISO-8859-1?Q?G=FCnther?= <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>,
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 David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
 Rob Herring <robh+dt@kernel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
 Conor Dooley <conor+dt@kernel.org>, linux-clk@vger.kernel.org,
 linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev,
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 devicetree@vger.kernel.org
Subject:
 Re: [PATCH v2 1/6] clk: sunxi-ng: nkm: Support constraints on m/n ratio and
 parent rate
Date: Tue, 06 Feb 2024 18:44:33 +0100
Message-ID: <2172947.irdbgypaU6@jernej-laptop>
In-Reply-To: <87il32ztp8.fsf@oltmanns.dev>
References:
 <20240205-pinephone-pll-fixes-v2-0-96a46a2d8c9b@oltmanns.dev>
 <2717565.mvXUDI8C0e@jernej-laptop> <87il32ztp8.fsf@oltmanns.dev>
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Dne ponedeljek, 05. februar 2024 ob 18:50:27 CET je Frank Oltmanns napisal(=
a):
> Hi Jernej,
>=20
> On 2024-02-05 at 18:45:27 +0100, Jernej =C5=A0krabec <jernej.skrabec@gmai=
l.com> wrote:
> > Dne ponedeljek, 05. februar 2024 ob 16:22:24 CET je Frank Oltmanns napi=
sal(a):
> >> The Allwinner A64 manual lists the following constraints for the
> >> PLL-MIPI clock:
> >>  - M/N <=3D 3
> >>  - (PLL_VIDEO0)/M >=3D 24MHz
> >>
> >> The PLL-MIPI clock is implemented as ccu_nkm. Therefore, add support f=
or
> >> these constraints.
> >>
> >> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
> >
> > Haven't we discussed that this patch is unnecessary because same effect=
 can
> > be reached by limiting minimum frequency?
>=20
> The patch for ccu_nm was unnecessary:
> https://lore.kernel.org/all/87jzoug2jz.fsf@oltmanns.dev/
>=20
> Unfortunately, we still need this one.

Ok, then:
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>

Best regards,
Jernej

>=20
> Best regards,
>   Frank
>=20
> >
> > Best regards,
> > Jernej
> >
> >> ---
> >>  drivers/clk/sunxi-ng/ccu_nkm.c | 21 +++++++++++++++++++++
> >>  drivers/clk/sunxi-ng/ccu_nkm.h |  2 ++
> >>  2 files changed, 23 insertions(+)
> >>
> >> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu=
_nkm.c
> >> index 853f84398e2b..1168d894d636 100644
> >> --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> >> +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> >> @@ -16,6 +16,20 @@ struct _ccu_nkm {
> >>  	unsigned long	m, min_m, max_m;
> >>  };
> >>
> >> +static bool ccu_nkm_is_valid_rate(struct ccu_common *common, unsigned=
 long parent,
> >> +				  unsigned long n, unsigned long m)
> >> +{
> >> +	struct ccu_nkm *nkm =3D container_of(common, struct ccu_nkm, common);
> >> +
> >> +	if (nkm->max_m_n_ratio && (m > nkm->max_m_n_ratio * n))
> >> +		return false;
> >> +
> >> +	if (nkm->min_parent_m_ratio && (parent < nkm->min_parent_m_ratio * m=
))
> >> +		return false;
> >> +
> >> +	return true;
> >> +}
> >> +
> >>  static unsigned long ccu_nkm_find_best_with_parent_adj(struct ccu_com=
mon *common,
> >>  						       struct clk_hw *parent_hw,
> >>  						       unsigned long *parent, unsigned long rate,
> >> @@ -31,6 +45,10 @@ static unsigned long ccu_nkm_find_best_with_parent_=
adj(struct ccu_common *common
> >>  				unsigned long tmp_rate, tmp_parent;
> >>
> >>  				tmp_parent =3D clk_hw_round_rate(parent_hw, rate * _m / (_n * _k)=
);
> >> +
> >> +				if (!ccu_nkm_is_valid_rate(common, tmp_parent, _n, _m))
> >> +					continue;
> >> +
> >>  				tmp_rate =3D tmp_parent * _n * _k / _m;
> >>
> >>  				if (ccu_is_better_rate(common, rate, tmp_rate, best_rate) ||
> >> @@ -64,6 +82,9 @@ static unsigned long ccu_nkm_find_best(unsigned long=
 parent, unsigned long rate,
> >>  	for (_k =3D nkm->min_k; _k <=3D nkm->max_k; _k++) {
> >>  		for (_n =3D nkm->min_n; _n <=3D nkm->max_n; _n++) {
> >>  			for (_m =3D nkm->min_m; _m <=3D nkm->max_m; _m++) {
> >> +				if (!ccu_nkm_is_valid_rate(common, parent, _n, _m))
> >> +					continue;
> >> +
> >>  				unsigned long tmp_rate;
> >>
> >>  				tmp_rate =3D parent * _n * _k / _m;
> >> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.h b/drivers/clk/sunxi-ng/ccu=
_nkm.h
> >> index 6601defb3f38..c409212ee40e 100644
> >> --- a/drivers/clk/sunxi-ng/ccu_nkm.h
> >> +++ b/drivers/clk/sunxi-ng/ccu_nkm.h
> >> @@ -27,6 +27,8 @@ struct ccu_nkm {
> >>  	struct ccu_mux_internal	mux;
> >>
> >>  	unsigned int		fixed_post_div;
> >> +	unsigned long		max_m_n_ratio;
> >> +	unsigned long		min_parent_m_ratio;
> >>
> >>  	struct ccu_common	common;
> >>  };
> >>
> >>
>=20