From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH v2 6/6] arm64: allwinner: a64: Increase the MMC max frequency Date: Wed, 11 Jan 2017 14:38:04 +0100 Message-ID: <20170111133804.m73q5u54qs3qhwe2@lukather> References: <3689701f93c8426bfa476e9a5f31c3642a8a898e.1483980339.git-series.maxime.ripard@free-electrons.com> <20170110191514.kgbesffn3xqltnol@lukather> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="kvv63k6iutwmeidz" Return-path: Content-Disposition: inline In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Chen-Yu Tsai Cc: Ulf Hansson , Rob Herring , devicetree , linux-arm-kernel , linux-kernel , "linux-mmc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Andre Przywara List-Id: devicetree@vger.kernel.org --kvv63k6iutwmeidz Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Wed, Jan 11, 2017 at 02:44:00PM +0800, Chen-Yu Tsai wrote: > On Wed, Jan 11, 2017 at 3:15 AM, Maxime Ripard > wrote: > > Hi, > > > > On Tue, Jan 10, 2017 at 01:01:20AM +0800, Chen-Yu Tsai wrote: > >> On Tue, Jan 10, 2017 at 12:46 AM, Maxime Ripard > >> wrote: > >> > All the controllers can have a maximum frequency of 200MHz. > >> > > >> > Since older SoCs cannot go that high, we cannot change the default m= aximum > >> > frequency, but fortunately for us we have a property for that in the= DT. > >> > > >> > This also has the side effect of allowing to use the MMC HS200 mode = for the > >> > boards that support it (with either 1.2v or 1.8v IOs). > >> > > >> > Signed-off-by: Maxime Ripard > >> > --- > >> > arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 3 +++ > >> > 1 file changed, 3 insertions(+), 0 deletions(-) > >> > > >> > diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi b/arch/ar= m64/boot/dts/allwinner/sun50i-a64.dtsi > >> > index 8e149498e096..f46ae965cf5b 100644 > >> > --- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi > >> > +++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi > >> > @@ -332,6 +332,7 @@ > >> > resets =3D <&ccu RST_BUS_MMC0>; > >> > reset-names =3D "ahb"; > >> > interrupts =3D ; > >> > + max-frequency =3D <200000000>; > >> > >> You also have to set one of MMC_CAP2_HS200* in the driver, > >> or mmc-hs200-1_8v or mmc-hs200-1_2v in the device tree to > >> actually use HS200, right? > > > > Yes, but that requires a board with 1.8V IOs to work properly, which > > not all board use, so it's probably best to enable it in the board > > DTS. >=20 > It's limited by the vqmmc regulator. Either way the host controller > supports it right? Yes, but if the card supports HS200 with 1.8V, and the controller reports it too, the core will pick that mode and will try to switch to it, which in turn will fail, making the card initialisation fail as well. We basically have two choices: either we ask all the boards that support it to set mmc-hs200-1_8v in their DTS, or we set it in the DTSI and we have the boards set no-1-8-v in their DTS if they do not support those modes. The first case is just the more convenient, because so far we've only seen one non-upstream (yet) board that supports 1.8V IOs. All the other do not. Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com --kvv63k6iutwmeidz Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIcBAEBCAAGBQJYdjU4AAoJEBx+YmzsjxAgrdIP/3J/ENwL7bYGh4hvZKHkxTcI 2gEEFDhgQqwqRQjrxexuTdXoWBN6FnHoHl83CX/6HVq7aVD5EXKl4V7jsK95mJJc EnAbBRcZnvVjWA0YP+uHgO0wC21FLwTDG1JwfOKJVfBKJlELSqvu2Tn3S5ATTj59 RtuN+oC9yzc606cQcbu6Z7z8Nxwmatr84KdK7wMJfDcTaOgVsSRpEFB3ewua1uSp +7MsLnxNOX9ZQPQ+W2hLIwMKEvbFBk8O/iDApRlY5CtmhycLifUXs0jz38nQ8DxT nMxl91GJdevcNvHOMLzclApAg1zQ9YAu2J5HfwI6epFykSyswA8dpgAQ94K3YQAO ChG/Lfov+xBy+NevoPBb4RpAbWTZU5x8qTwhSL0JQQp5ESoR1XWiE00QmTXjsY9k yE/Hzk5HaUMkprdiSnv2ZIb0cGN4DWj1BMMAQPT6ydj4c7avv82d8OXAbOVrWsCI aWN769yseDgCRBRvHSpvmtCssOa/8DUpOEnOwtDgsyjBhqJfLbdc9cY5Pnidruk3 sXj2/79JuPZWkip+IrtG/MfjW121HAUB+bZXSqG1hh20SHgtkKzOMDAJ+wdAXV5H eAFupS5I25PRfe/ulqAItpD35xxfa0DEl10UKLJtRP6eIJ4iX5V6hpEJmQxVo2vQ 3dw72PzP2mzA1DnQaCOo =9kty -----END PGP SIGNATURE----- --kvv63k6iutwmeidz-- -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html