From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH v3 1/13] mmc: sunxi: Fix clock frequency change sequence Date: Wed, 25 Jan 2017 09:26:02 +0100 Message-ID: <20170125082602.llunpuqwsimtzkds@lukather> References: <6f6b511bce9df86ee43486653ac55df0d135f198.1484585798.git-series.maxime.ripard@free-electrons.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="kwetivlh2i3v4f47" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org To: Ulf Hansson Cc: Chen-Yu Tsai , Rob Herring , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mmc@vger.kernel.org" , Andre Przywara List-Id: devicetree@vger.kernel.org --kwetivlh2i3v4f47 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Ulf, On Tue, Jan 24, 2017 at 09:12:07AM +0100, Ulf Hansson wrote: > On 16 January 2017 at 17:56, Maxime Ripard > wrote: > > The MMC and SD specifications documents that the clock frequency should > > only be changed once gated. >=20 > Where? >=20 > > > > The current code first modifies the parent clock, gates it and then > > modifies the internal divider. This means that since the parent clock r= ate > > might be changed, the bus clock might be changed as well before it is > > gated, which breaks the specification. > > > > Move the gating before the parent rate modification. >=20 > This all makes perfect sense to me, however I am not sure you need to > refer to the spec to justify these changes. I can't find it anymore :/ I'll resend that patch reworking the commit log. Thanks! Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com --kwetivlh2i3v4f47 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIcBAEBCAAGBQJYiGEWAAoJEBx+YmzsjxAgPMQQAK6Jv2hSrNnsIsGseMADAssc BY6CexdjRUlnJOJSE9vV8qNc6+rBtl8u1rgTvgJykS4nGV00W7OneeqeF4iSKmO3 9Pr4HZKnpGRiuDLl13sZhs8QZDDHPItPvgguUr/2E01mJx5LOsUTomH7u0kVN3MO EXbqKR8juIdnloHc9UBxG2yBl6WT3ImMfFcz7RlurQu/QvOi2Il0J8bNCzddfdCG hBbt0PZ67DVOyIcQadPVXb2IjgEFYEXkz7KCs1ISykittD+gPwmZZqfbjRcpX9E4 IEQBAaThdrBHrgvS1a1wwXEGSxCY+OCXb5J9aNwVsbqtm2oVBVEG/A9ppdJ9Fj8L 0SZ1ryb9QclW/Uv2kloNvi2B3rETfpPB9SE9JpzX+o+eUqudJFiz9idE45lCWYxm 6dNeg1X1UyfCr/9tf7lvi0L9sHYoWVJUVznqlxtDlGnODVtf2Nh98UTCvGXKn5xV /3xoZVTQHvBDSYb65mkvEEvWxB8OIALBoYTtGXrcqrsclFNNHcch6RXHYVajXZu/ ZsuW+sO4KR7rmJNFAnf4c/PoVrgls1Gzks1Wez5cVYvVBvm1eMwXDBzOnKw28gts HtEve1SOWhssEeN0tlrfOEeQb3Bmc78sVU2zo7S/GNWIBGAxNRJn89V5YagyeAMS VZwceo3+u10oDUfEDpX/ =nDkA -----END PGP SIGNATURE----- --kwetivlh2i3v4f47--