From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: [PATCH] mmc: core: Prevent eMMC VCC supply to be cut from late init Date: Wed, 9 May 2012 16:56:23 +0100 Message-ID: <20120509155622.GE3955@opensource.wolfsonmicro.com> References: <1336572926-21013-1-git-send-email-ulf.hansson@stericsson.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="2+IiqX0tbFQDLF7Q" Return-path: Received: from opensource.wolfsonmicro.com ([80.75.67.52]:38993 "EHLO opensource.wolfsonmicro.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758178Ab2EIP41 (ORCPT ); Wed, 9 May 2012 11:56:27 -0400 Content-Disposition: inline In-Reply-To: <1336572926-21013-1-git-send-email-ulf.hansson@stericsson.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Ulf Hansson Cc: linux-mmc@vger.kernel.org, Chris Ball , Per Forlin , Johan Rudholm , Lee Jones , Jasi Brar , Ulf Hansson --2+IiqX0tbFQDLF7Q Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, May 09, 2012 at 04:15:26PM +0200, Ulf Hansson wrote: > From: Ulf Hansson >=20 > For eMMC cards that has been initialized from a bootloader, > the VCC voltage supply must not be cut in an uncontrolled > manner, without first sending SLEEP or POWEROFF_NOTIFY. >=20 > The regulator_init_complete late initcall, may cut the VCC > regulator if it's reference counter is zero. To be able to > prevent the regulator from being cut, mmc_start_host, which > should execute at device init and thus before late init, > calls mmc_power_up. Then the host driver is able to increase > the reference to the regulator. This looks like a good, simple solution - working out how we avoid extra power ups will probably be more invasive and might not be worth the effort for something that's boot time only. Reviwed-by: Mark Brown --2+IiqX0tbFQDLF7Q Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJPqpOYAAoJEBus8iNuMP3dLRkP/1u2gOtDEd9iSozBecqN6iRK yKNYziQIKEXx2wqj7ZUdSn94+/QC9yHIHq3uOYXjpqxNDVXmcF0obt4EpDop34Yd iyZeN/xmyXJoI0QLy6+OxSKkyXNZZuI1OaK8bDfqAk+DhId4FoJ0Oi0Pwc5HlgiI 30/yCy6cKWDD0CsmgdlFKcOtz080ULLTuT4ZdDiKFmlcytCpIS30ARFBFwtFi0Ic Mj9lhy4K7sUjsZQ8dawWCz0ZWVdUgWNr3mHUD7QPQoDagh/dyIHgltnbiElyi74n EgMWPJRQItBg9LYeAeyNwh6uy7+oRUAcxhfEJifwL4r4oq2oaNt6SEaZxhplsbmX g3oMa8HqrSOxTzfBSUbtScFW0YodwhUbpxMQJcyA0cRrGwcd/zXvwhg4AedFTTgM MBMgns3dqZlqk36Wb6ZFQhL0qT8g/F9gNOUfC82PfIdUIf+NhrKuVBAFVBnUSQ8h T02Yh4RAYhni8xShcCfQJUFhO2PThFBjujYQD7sd1GaG76R9hnnQvjyY7ndpWs4I AOFd1Ly673ZcO/n7DDFHa/9gfU9DU2LD3jdjqw9eGnL6BJL7ka3fR9qkPFDlmzvs rvqWM5Du/fB0VvLD7A1Nkztl51uSIrMAX2q7CR/OARP0DmOdJ3VdSBgyle1iNdai dbHKiHL6MEq9DsDYiGJ3 =oAnk -----END PGP SIGNATURE----- --2+IiqX0tbFQDLF7Q--