From patchwork Tue Sep 29 09:10:42 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomeu Vizoso X-Patchwork-Id: 7284221 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id BD770BEEA4 for ; Tue, 29 Sep 2015 09:17:44 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CD579206BD for ; Tue, 29 Sep 2015 09:17:43 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E597E206B8 for ; Tue, 29 Sep 2015 09:17:42 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Zgr1H-0002Wl-Rb; Tue, 29 Sep 2015 09:16:19 +0000 Received: from mail-wi0-x22e.google.com ([2a00:1450:400c:c05::22e]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZgqxY-0000JZ-1A for linux-arm-kernel@lists.infradead.org; Tue, 29 Sep 2015 09:12:28 +0000 Received: by wiclk2 with SMTP id lk2so5890431wic.1 for ; Tue, 29 Sep 2015 02:12:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=iLzv7YFqEGev156/ZTYC2DJmz3+gHS1DOJMBh5rewOs=; b=xM9RNMRVkSd8TswaQKRYGM5peq60J4fj4ku2rchr3+cEv1Uwl8drVX0wUBV2By0orm nvAKDZtItovmdCP9r4nFAZl9aLb9HLGs3Bopxo9FDrZ6J+rkuwQiIBPeCI8VR6xTUab8 VgQqPbU0qXzWQm8oAnfYhtkbNEpzc/Ajhi1nrePVy+vqv08gMMvB/NaRztmJiVo9r0Xl GCq/YGJfwsyTBcgyx0q96Qr1thWeLseyq8NOqdJama2dZZGUlvTtnMDI5UtQWPFQOX9Q Hv1nNorBpddeM9Fsnfn+GxdzdSe4JcQTXd1D7KXC66shzQIHx4UiZxZPRrdw0qHokT32 8zAg== X-Received: by 10.194.222.227 with SMTP id qp3mr32215741wjc.36.1443517926400; Tue, 29 Sep 2015 02:12:06 -0700 (PDT) Received: from cizrna.lan ([109.72.12.204]) by smtp.gmail.com with ESMTPSA id lj12sm22757276wic.0.2015.09.29.02.12.04 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 29 Sep 2015 02:12:05 -0700 (PDT) From: Tomeu Vizoso To: linux-kernel@vger.kernel.org Subject: [PATCH v7 04/20] of: add function to allow probing a device from a OF node Date: Tue, 29 Sep 2015 11:10:42 +0200 Message-Id: <1443517859-30376-5-git-send-email-tomeu.vizoso@collabora.com> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1443517859-30376-1-git-send-email-tomeu.vizoso@collabora.com> References: <1443517859-30376-1-git-send-email-tomeu.vizoso@collabora.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150929_021228_241871_DFBA560A X-CRM114-Status: GOOD ( 19.35 ) X-Spam-Score: -2.4 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tomeu Vizoso , devicetree@vger.kernel.org, Ulf Hansson , linux-acpi@vger.kernel.org, Arnd Bergmann , Stephen Warren , Greg Kroah-Hartman , Linus Walleij , Dmitry Torokhov , "Rafael J. Wysocki" , Rob Herring , Javier Martinez Canillas , Mark Brown , Thierry Reding , Russell King , Alan Stern , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED, T_DKIM_INVALID, T_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 Walks the OF tree up and finds the closest ancestor that has a struct device associated with it, probing it if isn't bound to a driver yet. The above should ensure that the dependency represented by the passed OF node is available, because probing a device should cause its descendants to be probed as well (when they get registered). Subsystems can use this when looking up resources for drivers, to reduce the chances of deferred probes because of the probing order of devices. Signed-off-by: Tomeu Vizoso --- Changes in v5: - Move the assignment to device_node->device for AMBA devices to another commit. - Hold a reference to the struct device while it's in use in of_device_probe(). Changes in v4: - Rename of_platform_probe to of_device_probe - Use device_node.device instead of device_node.platform_dev Changes in v3: - Set and use device_node.platform_dev instead of reversing the logic to find the platform device that encloses a device node. - Drop the fwnode API to probe firmware nodes and add OF-only API for now. I think this same scheme could be used for machines with ACPI, but I haven't been able to find one that had to defer its probes because of the device probe order. drivers/of/device.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/of_device.h | 3 +++ 2 files changed, 64 insertions(+) diff --git a/drivers/of/device.c b/drivers/of/device.c index 8b91ea241b10..836be71fc90e 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -286,3 +286,64 @@ int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env) return 0; } + +/** + * of_device_probe() - Probe device associated with OF node + * @np: node to probe + * + * Probe the device associated with the passed device node. + */ +void of_device_probe(struct device_node *np) +{ + struct device_node *target; + struct device *dev = NULL; + + if (!of_root || !of_node_check_flag(of_root, OF_POPULATED_BUS)) + return; + + if (!np) + return; + + of_node_get(np); + + /* Find the closest ancestor that has a device associated */ + for (target = np; + !of_node_is_root(target); + target = of_get_next_parent(target)) + if (get_device(target->device)) { + dev = target->device; + break; + } + + of_node_put(target); + + if (!dev) { + pr_warn("Couldn't find a device for node '%s'\n", + of_node_full_name(np)); + return; + } + + /* + * Device is bound or is being probed right now. If we have bad luck + * and the dependency isn't ready when it's needed, deferred probe + * will save us. + */ + if (dev->driver) + goto out; + + /* + * Probing a device should cause its descendants to be probed as + * well, which includes the passed device node. + */ + if (device_attach(dev) != 1) + /* + * This cannot be a warning for now because clock nodes have a + * compatible string but the clock framework doesn't follow + * the device/driver model yet. + */ + dev_dbg(dev, "Probe failed for %s\n", of_node_full_name(np)); + +out: + put_device(dev); +} +EXPORT_SYMBOL_GPL(of_device_probe); diff --git a/include/linux/of_device.h b/include/linux/of_device.h index cc7dd687a89d..da8d489e73ad 100644 --- a/include/linux/of_device.h +++ b/include/linux/of_device.h @@ -40,6 +40,7 @@ extern ssize_t of_device_get_modalias(struct device *dev, extern void of_device_uevent(struct device *dev, struct kobj_uevent_env *env); extern int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env); +extern void of_device_probe(struct device_node *np); static inline void of_device_node_put(struct device *dev) { @@ -84,6 +85,8 @@ static inline int of_device_uevent_modalias(struct device *dev, return -ENODEV; } +static inline void of_device_probe(struct device_node *np) { } + static inline void of_device_node_put(struct device *dev) { } static inline const struct of_device_id *__of_match_device(