From patchwork Thu May 21 09:11:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Mack X-Patchwork-Id: 200205 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8D6AC433E3 for ; Thu, 21 May 2020 09:12:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A45E620759 for ; Thu, 21 May 2020 09:12:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728821AbgEUJMI (ORCPT ); Thu, 21 May 2020 05:12:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728813AbgEUJMH (ORCPT ); Thu, 21 May 2020 05:12:07 -0400 Received: from mail.bugwerft.de (mail.bugwerft.de [IPv6:2a03:6000:1011::59]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C9DE3C061A0E; Thu, 21 May 2020 02:12:06 -0700 (PDT) Received: from zenbar.fritz.box (pd95ef28a.dip0.t-ipconnect.de [217.94.242.138]) by mail.bugwerft.de (Postfix) with ESMTPSA id 47E7B40BCCC; Thu, 21 May 2020 09:09:05 +0000 (UTC) From: Daniel Mack To: devicetree@vger.kernel.org, linux-serial@vger.kernel.org Cc: gregkh@linuxfoundation.org, robh+dt@kernel.org, jslaby@suse.com, jringle@gridpoint.com, m.brock@vanmierlo.com, pascal.huerst@gmail.com, Daniel Mack Subject: [PATCH v3 5/6] sc16is7xx: Allow sharing the IRQ line Date: Thu, 21 May 2020 11:11:51 +0200 Message-Id: <20200521091152.404404-6-daniel@zonque.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200521091152.404404-1-daniel@zonque.org> References: <20200521091152.404404-1-daniel@zonque.org> MIME-Version: 1.0 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org When the interrupt line is shared with other devices, the IRQ must be level-triggered, as only one device can trigger a falling edge. To support this, try to acquire the IRQ with IRQF_TRIGGER_LOW|IRQF_SHARED first. Interrupt controllers that lack support for level-triggers will return an error, in which case the driver will now retry the acqusition with IRQF_TRIGGER_FALLING, which was also the default before. Signed-off-by: Daniel Mack --- drivers/tty/serial/sc16is7xx.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index cebc0cf9c30e..7e2360f8e393 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -1313,7 +1313,19 @@ static int sc16is7xx_probe(struct device *dev, s->p[u].irda_mode = true; } - /* Setup interrupt */ + /* + * Setup interrupt. We first try to acquire the IRQ line as level IRQ. + * If that succeeds, we can allow sharing the interrupt as well. + * In case the interrupt controller doesn't support that, we fall + * back to a non-shared falling-edge trigger. + */ + ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq, + IRQF_TRIGGER_LOW | IRQF_SHARED | + IRQF_ONESHOT, + dev_name(dev), s); + if (!ret) + return 0; + ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_irq, IRQF_TRIGGER_FALLING | IRQF_ONESHOT, dev_name(dev), s);