From patchwork Wed May 21 13:39:54 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 4217021 Return-Path: X-Original-To: patchwork-linux-fbdev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id EFBA8BEEAB for ; Wed, 21 May 2014 13:40:56 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 05E422034B for ; Wed, 21 May 2014 13:40:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 108682024C for ; Wed, 21 May 2014 13:40:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751940AbaEUNky (ORCPT ); Wed, 21 May 2014 09:40:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51257 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751911AbaEUNkw (ORCPT ); Wed, 21 May 2014 09:40:52 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s4LDeVxg017904 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 21 May 2014 09:40:37 -0400 Received: from shalem.localdomain.com (vpn1-4-250.ams2.redhat.com [10.36.4.250]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id s4LDdviT032136; Wed, 21 May 2014 09:40:18 -0400 From: Hans de Goede To: "Rafael J. Wysocki" , Aaron Lu , Jingoo Han , Bryan Wu , Lee Jones , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , Ben Skeggs , David Airlie Cc: Zhang Rui , Len Brown , linux-acpi@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Hans de Goede Subject: [PATCH resend 2/4] backlight: Add backlight device (un)registration notification Date: Wed, 21 May 2014 15:39:54 +0200 Message-Id: <1400679596-19663-3-git-send-email-hdegoede@redhat.com> In-Reply-To: <1400679596-19663-1-git-send-email-hdegoede@redhat.com> References: <1400679596-19663-1-git-send-email-hdegoede@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Some firmware drivers, ie acpi-video want to get themselves out of the way (in some cases) when their also is a raw backlight device available. Due to module loading ordering being unknown, acpi-video cannot be certain that the backlight_device_registered(BACKLIGHT_RAW) it does for this is the final verdict wrt there being a BACKLIGHT_RAW device. By adding notification acpi-video can listen for backlight devices showing up after it has loaded, and unregister its backlight device if desired. Signed-off-by: Hans de Goede Acked-by: Jingoo Han --- drivers/video/backlight/backlight.c | 40 +++++++++++++++++++++++++++++++++++++ include/linux/backlight.h | 7 +++++++ 2 files changed, 47 insertions(+) diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c index bd2172c..4280890 100644 --- a/drivers/video/backlight/backlight.c +++ b/drivers/video/backlight/backlight.c @@ -23,6 +23,7 @@ static struct list_head backlight_dev_list; static struct mutex backlight_dev_list_mutex; +static struct blocking_notifier_head backlight_notifier; static const char *const backlight_types[] = { [BACKLIGHT_RAW] = "raw", @@ -370,6 +371,9 @@ struct backlight_device *backlight_device_register(const char *name, list_add(&new_bd->entry, &backlight_dev_list); mutex_unlock(&backlight_dev_list_mutex); + blocking_notifier_call_chain(&backlight_notifier, + BACKLIGHT_REGISTERED, new_bd); + return new_bd; } EXPORT_SYMBOL(backlight_device_register); @@ -413,6 +417,10 @@ void backlight_device_unregister(struct backlight_device *bd) pmac_backlight = NULL; mutex_unlock(&pmac_backlight_mutex); #endif + + blocking_notifier_call_chain(&backlight_notifier, + BACKLIGHT_UNREGISTERED, bd); + mutex_lock(&bd->ops_lock); bd->ops = NULL; mutex_unlock(&bd->ops_lock); @@ -438,6 +446,36 @@ static int devm_backlight_device_match(struct device *dev, void *res, } /** + * backlight_register_notifier - get notified of backlight (un)registration + * @nb: notifier block with the notifier to call on backlight (un)registration + * + * @return 0 on success, otherwise a negative error code + * + * Register a notifier to get notified when backlight devices get registered + * or unregistered. + */ +int backlight_register_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&backlight_notifier, nb); +} +EXPORT_SYMBOL(backlight_register_notifier); + +/** + * backlight_unregister_notifier - unregister a backlight notifier + * @nb: notifier block to unregister + * + * @return 0 on success, otherwise a negative error code + * + * Register a notifier to get notified when backlight devices get registered + * or unregistered. + */ +int backlight_unregister_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&backlight_notifier, nb); +} +EXPORT_SYMBOL(backlight_unregister_notifier); + +/** * devm_backlight_device_register - resource managed backlight_device_register() * @dev: the device to register * @name: the name of the device @@ -544,6 +582,8 @@ static int __init backlight_class_init(void) backlight_class->pm = &backlight_class_dev_pm_ops; INIT_LIST_HEAD(&backlight_dev_list); mutex_init(&backlight_dev_list_mutex); + BLOCKING_INIT_NOTIFIER_HEAD(&backlight_notifier); + return 0; } diff --git a/include/linux/backlight.h b/include/linux/backlight.h index 7264742..adb14a8 100644 --- a/include/linux/backlight.h +++ b/include/linux/backlight.h @@ -40,6 +40,11 @@ enum backlight_type { BACKLIGHT_TYPE_MAX, }; +enum backlight_notification { + BACKLIGHT_REGISTERED, + BACKLIGHT_UNREGISTERED, +}; + struct backlight_device; struct fb_info; @@ -133,6 +138,8 @@ extern void devm_backlight_device_unregister(struct device *dev, extern void backlight_force_update(struct backlight_device *bd, enum backlight_update_reason reason); extern bool backlight_device_registered(enum backlight_type type); +extern int backlight_register_notifier(struct notifier_block *nb); +extern int backlight_unregister_notifier(struct notifier_block *nb); #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)