From mboxrd@z Thu Jan 1 00:00:00 1970 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=-15.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 6EA45C43461 for ; Tue, 15 Sep 2020 14:38:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 399E1206A4 for ; Tue, 15 Sep 2020 14:38:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600180686; bh=tHrh5VR63ed/BO5xJkXkOiyyZEqaggP7oWHcWOYt3L4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AL2RrwphGMBVqcu14gs4EHeySusnEs1F3oFM42PUwifINN8JU+4ARBeYi9kkNILhm wnkwI7hP47y7D+UiXaiNbffmFXdyNOjq9Jsy4nI/xnCROk7xyNMx3MngOGYBFYiBBp 1UqU/2Cn5SQUuMO8k8mgspnwlQVr0equNNyJJyGo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727201AbgIOOiC (ORCPT ); Tue, 15 Sep 2020 10:38:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:48766 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727164AbgIOOhi (ORCPT ); Tue, 15 Sep 2020 10:37:38 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C0ACD2242C; Tue, 15 Sep 2020 14:27:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600180035; bh=tHrh5VR63ed/BO5xJkXkOiyyZEqaggP7oWHcWOYt3L4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qDzPfxqvwwC1ZicwQhyi15fal4YaO+n3NjK9X67KW6CIw1XDNDLgiF9mzV1eTt+eK Nma3sF9XpB7ptgKqTbClwPCnp5qIOVZ4P4Mn6LRXJYHImqCYHBl0da/1F+gNaE4ZFz Fvuw8e+7ULKF9wNi/2OxyUKem6/1RO0iWvzbq6M4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sean Young , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH 5.8 082/177] media: gpio-ir-tx: spinlock is not needed to disable interrupts Date: Tue, 15 Sep 2020 16:12:33 +0200 Message-Id: <20200915140657.572571613@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140653.610388773@linuxfoundation.org> References: <20200915140653.610388773@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sean Young [ Upstream commit 1451b93223bbe3b4e9c91fca6b451d00667c5bf0 ] During bit-banging the IR on a gpio pin, we cannot be scheduled or have anything interrupt us, else the generated signal will be incorrect. Therefore, we need to disable interrupts on the local cpu. This also disables preemption. local_irq_disable() does exactly what we need and does not require a spinlock. Signed-off-by: Sean Young Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/rc/gpio-ir-tx.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/drivers/media/rc/gpio-ir-tx.c b/drivers/media/rc/gpio-ir-tx.c index f33b443bfa47b..c6cd2e6d8e654 100644 --- a/drivers/media/rc/gpio-ir-tx.c +++ b/drivers/media/rc/gpio-ir-tx.c @@ -19,8 +19,6 @@ struct gpio_ir { struct gpio_desc *gpio; unsigned int carrier; unsigned int duty_cycle; - /* we need a spinlock to hold the cpu while transmitting */ - spinlock_t lock; }; static const struct of_device_id gpio_ir_tx_of_match[] = { @@ -53,12 +51,11 @@ static int gpio_ir_tx_set_carrier(struct rc_dev *dev, u32 carrier) static void gpio_ir_tx_unmodulated(struct gpio_ir *gpio_ir, uint *txbuf, uint count) { - unsigned long flags; ktime_t edge; s32 delta; int i; - spin_lock_irqsave(&gpio_ir->lock, flags); + local_irq_disable(); edge = ktime_get(); @@ -72,14 +69,11 @@ static void gpio_ir_tx_unmodulated(struct gpio_ir *gpio_ir, uint *txbuf, } gpiod_set_value(gpio_ir->gpio, 0); - - spin_unlock_irqrestore(&gpio_ir->lock, flags); } static void gpio_ir_tx_modulated(struct gpio_ir *gpio_ir, uint *txbuf, uint count) { - unsigned long flags; ktime_t edge; /* * delta should never exceed 0.5 seconds (IR_MAX_DURATION) and on @@ -95,7 +89,7 @@ static void gpio_ir_tx_modulated(struct gpio_ir *gpio_ir, uint *txbuf, space = DIV_ROUND_CLOSEST((100 - gpio_ir->duty_cycle) * (NSEC_PER_SEC / 100), gpio_ir->carrier); - spin_lock_irqsave(&gpio_ir->lock, flags); + local_irq_disable(); edge = ktime_get(); @@ -128,19 +122,20 @@ static void gpio_ir_tx_modulated(struct gpio_ir *gpio_ir, uint *txbuf, edge = last; } } - - spin_unlock_irqrestore(&gpio_ir->lock, flags); } static int gpio_ir_tx(struct rc_dev *dev, unsigned int *txbuf, unsigned int count) { struct gpio_ir *gpio_ir = dev->priv; + unsigned long flags; + local_irq_save(flags); if (gpio_ir->carrier) gpio_ir_tx_modulated(gpio_ir, txbuf, count); else gpio_ir_tx_unmodulated(gpio_ir, txbuf, count); + local_irq_restore(flags); return count; } @@ -176,7 +171,6 @@ static int gpio_ir_tx_probe(struct platform_device *pdev) gpio_ir->carrier = 38000; gpio_ir->duty_cycle = 50; - spin_lock_init(&gpio_ir->lock); rc = devm_rc_register_device(&pdev->dev, rcdev); if (rc < 0) -- 2.25.1