From patchwork Thu Mar 2 17:31:14 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandre Belloni X-Patchwork-Id: 9601195 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7EA9D60429 for ; Thu, 2 Mar 2017 17:32:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6FEA827F8F for ; Thu, 2 Mar 2017 17:32:11 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 63A0328527; Thu, 2 Mar 2017 17:32:11 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id D857427F8F for ; Thu, 2 Mar 2017 17:32:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=kjt8WQ1Uwo1kpCywKn/wUIeUCc0izYGZJUYEzrnW2EE=; b=uXPJUTKt3WGkr3xhqnepkOQ1qy k9x9reGMVifzAh7XgqDAXtYY3FI95k6KxDaIlDWkoqMes5OZIuyCxmR7Jlcgo2EF32DfrLjspr2BU Nr+/LTLDgDRvWxjvDq1s7i6FaXdzivYooA1YB/fBGuefPd9f/BEATAAIgx26pK7c15+DXZNr/csGI pZskgzqGVAxa6ghUReICNsMndtELQu+NRgRWH+JFr/Tjz5vcB6zbFEsVqUCk60/f1sjq6lGTr3kVw UjXbfkUXZ7zwPt5mhTtjDgIJvqP1qeYZwAcDNIKQk5/U4MWr1oFIHroC+H7Vlo9KopEyraqSkCgcU kpjBZZAg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cjUaH-0005AT-4Z; Thu, 02 Mar 2017 17:32:09 +0000 Received: from mail.free-electrons.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cjUZs-00058X-AO for linux-arm-kernel@lists.infradead.org; Thu, 02 Mar 2017 17:31:46 +0000 Received: by mail.free-electrons.com (Postfix, from userid 110) id 168C220B77; Thu, 2 Mar 2017 18:31:20 +0100 (CET) Received: from localhost (unknown [88.191.26.124]) by mail.free-electrons.com (Postfix) with ESMTPSA id EA189206E1; Thu, 2 Mar 2017 18:31:19 +0100 (CET) From: Alexandre Belloni To: Guenter Roeck Subject: [PATCH 4/4] watchdog: sama5d4: Add comment explaining what happens on resume Date: Thu, 2 Mar 2017 18:31:14 +0100 Message-Id: <20170302173114.28508-5-alexandre.belloni@free-electrons.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170302173114.28508-1-alexandre.belloni@free-electrons.com> References: <20170302173114.28508-1-alexandre.belloni@free-electrons.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170302_093144_517698_4A48EC4C X-CRM114-Status: GOOD ( 11.27 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-watchdog@vger.kernel.org, Wenyou.Yang@microchip.com, linux-kernel@vger.kernel.org, Nicolas Ferre , Wim Van Sebroeck , Alexandre Belloni , 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-Virus-Scanned: ClamAV using ClamSMTP Because suspending to RAM may lose the register values, they are restored on resume. This is currently done unconditionally because there is currently no way to know (from the driver) whether they have really been lost or are still valid. Writing MR also pings the watchdog and this may not be what is expected so add a comment explaining why it happens. Signed-off-by: Alexandre Belloni Reviewed-by: Guenter Roeck --- drivers/watchdog/sama5d4_wdt.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c index d710014f3b7d..0ae947c3d7bc 100644 --- a/drivers/watchdog/sama5d4_wdt.c +++ b/drivers/watchdog/sama5d4_wdt.c @@ -300,6 +300,11 @@ static int sama5d4_wdt_resume(struct device *dev) { struct sama5d4_wdt *wdt = dev_get_drvdata(dev); + /* + * FIXME: writing MR also pings the watchdog which may not be desired. + * This should only be done when the registers are lost on suspend but + * there is no way to get this information right now. + */ sama5d4_wdt_init(wdt); return 0;