Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755911AbZCLCca (ORCPT ); Wed, 11 Mar 2009 22:32:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753343AbZCLCcU (ORCPT ); Wed, 11 Mar 2009 22:32:20 -0400 Received: from smtp125.sbc.mail.sp1.yahoo.com ([69.147.65.184]:24580 "HELO smtp125.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751015AbZCLCcT (ORCPT ); Wed, 11 Mar 2009 22:32:19 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=pacbell.net; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=rtRVkmKj9gJSDQHCArnj9X0ieWq5/gSWHxNLeH5sIdqLNyJiRc1CBzl2SLa6m8hbb09JXGU1/E53O4ePVzsjLL/SSIyrPjQcMnAkCAEg1+5Dah0VqMBVR7aV44P0j7v+11B7M02uKMBgBzKd+taux4vIsgOfLaIP1axN163nI4Y= ; X-YMail-OSG: AsbX2NsVM1moA70A43Rk3piye0T4gLj3L56icStc3f01uJheJ9Yd7wfchZtbHQ.226tpNQBLfAg5OFLhGq8YcZrH8j0FdEDsEgBSMmdvNmfDkjL4vkd.OJq5FvKYTPzWQ521WmMYVDyLF_ygXhUk7ZsMoJ7PMRwP9VRyB9NOxcvYZ4tLXokVt24IFrPrr1P.UA-- X-Yahoo-Newman-Property: ymail-3 From: David Brownell To: Liam Girdwood , Mark Brown Subject: [patch 2.6.29-rc7 regulator-next] regulator: init fixes Date: Wed, 11 Mar 2009 18:32:15 -0800 User-Agent: KMail/1.9.10 Cc: lkml , OMAP References: <200903111743.34708.david-b@pacbell.net> In-Reply-To: <200903111743.34708.david-b@pacbell.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200903111932.16317.david-b@pacbell.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4028 Lines: 116 From: David Brownell Make the regulator setup code cope more consistently with regulators undesirably left enabled by the bootloader. Building on the previous refcount patch: * Unless the "boot_on" or "always_on" machine constraints were set, disable() the regulator. This gives drivers a clean start state: enable state matches usecount, regardless of boot_on/always_on flag state. * To help make some integration stages easier, add a new "devmode" machine constraint where state the bootloader left isn't touched, but enable state and usecount may not match. (System boots but some drivers act odd ... debuggable. System dies part way through booting ... often painful.) Consider a bootloader that leaves an MMC/SD regulator active when it loads Linux from an SD card. It may take some time before the MMC/SD driver gets loaded, if ever ... to save power, that (LDO) regulator should be disabled ASAP. Then later when the MMC driver starts up, the Linux MMC stack will need to start from a "power off" state. It can't just if (regulator_is_enabled(r)) regulator_disable(r); unless enable state and usecount are matched ... but without this patch, they *will* be mismatched whenever the bootloader happens to have left that regulator active! Similar issues can crop up with almost any regulator. Signed-off-by: David Brownell --- drivers/regulator/core.c | 47 +++++++++++++++++++++++++++++------- include/linux/regulator/machine.h | 3 +- 2 files changed, 40 insertions(+), 10 deletions(-) --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -799,18 +799,47 @@ static int set_machine_constraints(struc } } - /* If the constraints say the regulator should be on at this point - * and we have control then make sure it is enabled. + /* During integration, developers may need time to sort out what + * to do with this regulator; leave the bootloader's setting alone. + * Regulator consumers won't get consistent behavior. + * + * Else the constraints say whether it should be on or off; we + * don't leave it in an unknown state. */ - if ((constraints->always_on || constraints->boot_on) && ops->enable) { - ret = ops->enable(rdev); - if (ret < 0) { - printk(KERN_ERR "%s: failed to enable %s\n", - __func__, name); - rdev->constraints = NULL; - goto out; + if (constraints->devmode) { + char *label = "unknown"; + + if (ops->is_enabled) { + ret = ops->is_enabled(rdev); + if (ret == 0) + label = "disabled"; + else if (ret > 0) + label = "enabled"; + ret = 0; + } + pr_warning("%s: devmode regulator '%s' state is '%s'\n", + __func__, name, label); + } else if (constraints->always_on || constraints->boot_on) { + if (ops->enable) { + ret = ops->enable(rdev); + if (ret < 0) { + pr_err("%s: failed enabling %s\n", + __func__, name); + rdev->constraints = NULL; + goto out; + } } rdev->use_count = 1; + } else { + if (ops->disable) { + ret = ops->disable(rdev); + if (ret < 0) { + pr_err("%s: failed disabling %s\n", + __func__, name); + rdev->constraints = NULL; + goto out; + } + } } print_constraints(rdev); --- a/include/linux/regulator/machine.h +++ b/include/linux/regulator/machine.h @@ -117,7 +117,8 @@ struct regulation_constraints { /* mode to set on startup */ unsigned int initial_mode; - /* constriant flags */ + /* constraint flags */ + unsigned devmode:1; /* state after setup is indeterminate */ unsigned always_on:1; /* regulator never off when system is on */ unsigned boot_on:1; /* bootloader/firmware enabled regulator */ unsigned apply_uV:1; /* apply uV constraint iff min == max */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/