From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH v2 11/15] clk: sunxi-ng: Add N-M-factor clock support Date: Mon, 27 Jun 2016 22:29:37 +0200 Message-ID: <20160627202937.GY4000@lukather> References: <20160607204154.31967-1-maxime.ripard@free-electrons.com> <20160607204154.31967-12-maxime.ripard@free-electrons.com> <20160609094101.426a13c4c61aa6cb11df16fc@free.fr> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="0786ZyFfTSxuegBe" Return-path: Content-Disposition: inline In-Reply-To: <20160609094101.426a13c4c61aa6cb11df16fc@free.fr> Sender: linux-clk-owner@vger.kernel.org To: Jean-Francois Moine Cc: Mike Turquette , Stephen Boyd , Chen-Yu Tsai , linux-clk@vger.kernel.org, Hans de Goede , Andre Przywara , Rob Herring , Vishnu Patekar , linux-arm-kernel@lists.infradead.org, Boris Brezillon , linux-kernel@vger.kernel.org, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org --0786ZyFfTSxuegBe Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Thu, Jun 09, 2016 at 09:41:01AM +0200, Jean-Francois Moine wrote: > On Tue, 7 Jun 2016 22:41:50 +0200 > Maxime Ripard wrote: >=20 > > Introduce support for clocks that multiply and divide using linear fact= ors. > >=20 > > Signed-off-by: Maxime Ripard > >=20 > > --- > > Changes from v1: > > - Fixed the maximums for both factors passed to the rational factor > > computation. > > --- > > drivers/clk/sunxi-ng/Makefile | 1 + > > drivers/clk/sunxi-ng/ccu_nm.c | 114 ++++++++++++++++++++++++++++++++++= ++++++++ > > drivers/clk/sunxi-ng/ccu_nm.h | 95 +++++++++++++++++++++++++++++++++++ > > 3 files changed, 210 insertions(+) > > create mode 100644 drivers/clk/sunxi-ng/ccu_nm.c > > create mode 100644 drivers/clk/sunxi-ng/ccu_nm.h > >=20 > > diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makef= ile > > index a201fad6b11d..5c7ae1ad1082 100644 > > --- a/drivers/clk/sunxi-ng/Makefile > > +++ b/drivers/clk/sunxi-ng/Makefile > > @@ -9,4 +9,5 @@ obj-y +=3D ccu_gate.o > > obj-y +=3D ccu_mp.o > > obj-y +=3D ccu_mux.o > > obj-y +=3D ccu_nk.o > > +obj-y +=3D ccu_nm.o > > obj-y +=3D ccu_phase.o > > diff --git a/drivers/clk/sunxi-ng/ccu_nm.c b/drivers/clk/sunxi-ng/ccu_n= m.c > > new file mode 100644 > > index 000000000000..e35ddd8eec8b > > --- /dev/null > > +++ b/drivers/clk/sunxi-ng/ccu_nm.c > > @@ -0,0 +1,114 @@ > > +/* > > + * Copyright (C) 2016 Maxime Ripard > > + * Maxime Ripard > > + * > > + * This program is free software; you can redistribute it and/or > > + * modify it under the terms of the GNU General Public License as > > + * published by the Free Software Foundation; either version 2 of > > + * the License, or (at your option) any later version. > > + */ > > + > > +#include > > +#include > > + > > +#include "ccu_frac.h" > > +#include "ccu_gate.h" > > +#include "ccu_nm.h" > [snip] > > +static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw, > > + unsigned long parent_rate) > > +{ > > + struct ccu_nm *nm =3D hw_to_ccu_nm(hw); > > + unsigned long n, m; > > + u32 reg; > > + > > + if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac)) > > + return ccu_frac_helper_read_rate(&nm->common, &nm->frac); > > + > > + reg =3D readl(nm->common.base + nm->common.reg); > > + > > + n =3D reg >> nm->n.shift; > > + n &=3D (1 << nm->n.width) - 1; > > + > > + m =3D reg >> nm->m.shift; > > + m &=3D (1 << nm->m.width) - 1; > > + > > + return parent_rate * (n + 1) / (m + 1); >=20 > In the H3, 'm' is a pre-divider (audio and video PLLs): >=20 > return parent_rate / (m + 1) * (n + 1); That's true, but the "true" N-M clocks exist and are using this formula (like the Audio PLL on A10's). If (and when) that causes some rounding issues, we can always add pre-divider support to N-Clocks that we are going to need anyway for the older SoCs. Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --0786ZyFfTSxuegBe Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJXcYyxAAoJEBx+YmzsjxAgy8IQAK3ieSbN2byn5uWey4B5e6F0 49phxN9nF9xGWWeiIW9bHNgC18t/v0+5/JhtpxWyq0W+R4YQnPcNSbS4MZStUXES dJCo4ycNCAiyrlgljXRhFbE3heZIz4Ot8u9VEpbnmFRWqUYksmNYFVvcfqNspXH6 iyRExzBfvMAcc5wRGTd/eezlcb+LzUN7LSAEP7kGB2mjZSooJWu8J/w/cHQjxOVZ N51s417w3xxTLEoHWn3GEuD6y5GHnddHD0eqAyzSX2f+ubb+D8BJkMa7ths93Ok5 qr7W95YEQNbjHP6W+q/AOrvF4fKRtSFC4eScE9ux+vFfYXA2CWmuelmbTz324RDU sPuoKXt02ma9lYKtFZyerbbICbFsCAKS3VYUKfa9trZne4VC9IXvwq6TTQg2E1TG vucz0TixnVQ2ru1VXv/qrxV1LqOMem9NReRY+VBrR9kdnoi0wMqEk5THTL0Dwivv SAcBOuiV54f7HHU7EA5VvjTI6ilxjL2CTqgavXMidQYUSkd+V0Xj1cPoGqieSP2V h94IKJ26XRnFQn+nq08RlW9fjwoxrKE/4WyafihP/2gXJ+RFWiA+EOPJnC9+o5Sr Ey0oSxR5eofwUGLVztw+tAdmOApHL0W3UhepzoKJVC1uS/2FOiKT3WQkbVhuU2X0 Oo2xm5Er57DS5EJ/oP1O =6ZjI -----END PGP SIGNATURE----- --0786ZyFfTSxuegBe--