From patchwork Tue Jul 28 15:27:09 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tim Harvey X-Patchwork-Id: 6887441 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 32935C05AC for ; Tue, 28 Jul 2015 15:29:57 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3AFCB205BE for ; Tue, 28 Jul 2015 15:29:56 +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 3AA3420570 for ; Tue, 28 Jul 2015 15:29:55 +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 1ZK6nZ-0007Pk-RE; Tue, 28 Jul 2015 15:28:09 +0000 Received: from mail-pd0-f178.google.com ([209.85.192.178]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZK6nB-000756-I0 for linux-arm-kernel@lists.infradead.org; Tue, 28 Jul 2015 15:27:46 +0000 Received: by pdjr16 with SMTP id r16so73779862pdj.3 for ; Tue, 28 Jul 2015 08:27:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=Ecz+x+J/fZRpRgfFtoH/hYzzhmQJqFpNHYMzON/NwNw=; b=IS53trkExpqB1wuL6+akFS5HwX51xvWUMbSbDIJNACqDJvZCKElpPhgBayqB9OBrgo RDsLZkklH7HF27kLdNcwGBWrZXLeSiUTPvdJlJsoeHsIhxU/2ok01mcH1VCTq+tIfgvO pEV9MyTd16goBtsdbeIpPMTcBxnfAcJSglAwZHnzxUmAt136P3u7xi9a8HLrYIfyo4rJ d/gyY4Mrss5eSlbo4GTqeAupdPEcl50VeGi0UmQm6mOPlb9MWJI9RN0h/GwoC7J3mgxO ltyyrZMj3VZG6SQ6kEoPZ3v287vdx9wmJ1cQUZmxYod6lJf2rb1ZOX24NBTpU9wuh5MB WTPg== X-Gm-Message-State: ALoCoQnKL3FQ4nvQOc/U7yTme+EMe+Y2aomg0esAt+W+5gGVLxdJi6i2P/cbqSJdIVrV9DaFHx3g X-Received: by 10.70.30.193 with SMTP id u1mr81117619pdh.59.1438097244528; Tue, 28 Jul 2015 08:27:24 -0700 (PDT) Received: from tharvey.gw (68-189-91-139.static.snlo.ca.charter.com. [68.189.91.139]) by smtp.gmail.com with ESMTPSA id v4sm3635559pdg.79.2015.07.28.08.27.22 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 28 Jul 2015 08:27:23 -0700 (PDT) From: Tim Harvey To: Shawn Guo Subject: [PATCH v3 1/2] watchdog: imx2_wdt: add external reset support via 'ext-reset-output' dt prop Date: Tue, 28 Jul 2015 08:27:09 -0700 Message-Id: <1438097230-2653-2-git-send-email-tharvey@gateworks.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1438097230-2653-1-git-send-email-tharvey@gateworks.com> References: <1433448960-9257-2-git-send-email-tharvey@gateworks.com> <1438097230-2653-1-git-send-email-tharvey@gateworks.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150728_082745_624639_53631836 X-CRM114-Status: GOOD ( 16.66 ) X-Spam-Score: -2.6 (--) 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: Sascha Hauer , Lucas Stach , Stefan Roese , Fabio Estevam , linux-arm-kernel@lists.infradead.org, Iain Paton 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=-5.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, 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 The IMX6 watchdog supports assertion of a signal (WDOG_B) which can be pinmux'd to an external pin. This is typically used for boards that have PMIC's in control of the IMX6 power rails. In fact, failure to use such an external reset on boards with external PMIC's can result in various hangs due to the IMX6 not being fully reset [1] as well as the board failing to reset because its PMIC has not been reset to provide adequate voltage for the CPU when coming out of reset at 800Mhz. This uses a new device-tree property 'ext-reset-output' to indicate the board has such a reset and to cause the watchdog to be configured to assert WDOG_B instead of an internal reset both on a watchdog timeout and in system_restart. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/333689.html Cc: Lucas Stach Signed-off-by: Tim Harvey Acked-by: Shawn Guo --- v3: - mandate use of 'either' internal or external reset but not both simultaneously v2: - rename property to 'ext-reset-output' based on ML feedback - simplify setting SRS bit if external-reset - update comments and commit msg Signed-off-by: Tim Harvey --- .../devicetree/bindings/watchdog/fsl-imx-wdt.txt | 2 ++ drivers/watchdog/imx2_wdt.c | 20 ++++++++++++++++++-- 2 files changed, 20 insertions(+), 2 deletions(-) diff --git a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt index 8dab6fd..9b89b3a 100644 --- a/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt +++ b/Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.txt @@ -9,6 +9,8 @@ Optional property: - big-endian: If present the watchdog device's registers are implemented in big endian mode, otherwise in native mode(same with CPU), for more detail please see: Documentation/devicetree/bindings/regmap/regmap.txt. +- ext-reset-output: If present the watchdog device is configured to assert its + external reset (WDOG_B) instead of issuing a software reset. Examples: diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c index 0bb1a1d..5d9ccf6 100644 --- a/drivers/watchdog/imx2_wdt.c +++ b/drivers/watchdog/imx2_wdt.c @@ -41,6 +41,8 @@ #define IMX2_WDT_WCR 0x00 /* Control Register */ #define IMX2_WDT_WCR_WT (0xFF << 8) /* -> Watchdog Timeout Field */ +#define IMX2_WDT_WCR_WDA (1 << 5) /* -> External Reset WDOG_B */ +#define IMX2_WDT_WCR_SRS (1 << 4) /* -> Software Reset Signal */ #define IMX2_WDT_WCR_WRE (1 << 3) /* -> WDOG Reset Enable */ #define IMX2_WDT_WCR_WDE (1 << 2) /* -> Watchdog Enable */ #define IMX2_WDT_WCR_WDZST (1 << 0) /* -> Watchdog timer Suspend */ @@ -65,6 +67,7 @@ struct imx2_wdt_device { struct timer_list timer; /* Pings the watchdog when closed */ struct watchdog_device wdog; struct notifier_block restart_handler; + bool ext_reset; }; static bool nowayout = WATCHDOG_NOWAYOUT; @@ -90,6 +93,13 @@ static int imx2_restart_handler(struct notifier_block *this, unsigned long mode, struct imx2_wdt_device *wdev = container_of(this, struct imx2_wdt_device, restart_handler); + + /* Use internal reset or external - not both */ + if (wdev->ext_reset) + wcr_enable |= IMX2_WDT_WCR_SRS; /* do not assert int reset */ + else + wcr_enable |= IMX2_WDT_WCR_WDA; /* do not assert ext-reset */ + /* Assert SRS signal */ regmap_write(wdev->regmap, 0, wcr_enable); /* @@ -119,8 +129,12 @@ static inline void imx2_wdt_setup(struct watchdog_device *wdog) val |= IMX2_WDT_WCR_WDZST; /* Strip the old watchdog Time-Out value */ val &= ~IMX2_WDT_WCR_WT; - /* Generate reset if WDOG times out */ - val &= ~IMX2_WDT_WCR_WRE; + /* Generate internal chip-level reset if WDOG times out */ + if (!wdev->ext_reset) + val &= ~IMX2_WDT_WCR_WRE; + /* Or if external-reset assert WDOG_B reset only on time-out */ + else + val |= IMX2_WDT_WCR_WRE; /* Keep Watchdog Disabled */ val &= ~IMX2_WDT_WCR_WDE; /* Set the watchdog's Time-Out value */ @@ -267,6 +281,8 @@ static int __init imx2_wdt_probe(struct platform_device *pdev) regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val); wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0; + wdev->ext_reset = of_property_read_bool(pdev->dev.of_node, + "ext-reset-output"); wdog->timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME); if (wdog->timeout != timeout) dev_warn(&pdev->dev, "Initial timeout out of range! Clamped from %u to %u\n",