From patchwork Mon Apr 14 08:21:48 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philipp Zabel X-Patchwork-Id: 3978121 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 [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 202D9BFF02 for ; Mon, 14 Apr 2014 08:24:47 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3B3B0201EC for ; Mon, 14 Apr 2014 08:24:46 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C4DD0201E4 for ; Mon, 14 Apr 2014 08:24:44 +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 1WZc9x-0001jL-GV; Mon, 14 Apr 2014 08:22:33 +0000 Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WZc9u-00015o-6w for linux-arm-kernel@lists.infradead.org; Mon, 14 Apr 2014 08:22:30 +0000 Received: from paszta.hi.pengutronix.de ([10.1.0.120] helo=paszta.pengutronix.de.) by metis.ext.pengutronix.de with esmtp (Exim 4.72) (envelope-from ) id 1WZc9O-0002JQ-HD; Mon, 14 Apr 2014 10:21:58 +0200 From: Philipp Zabel To: linux-kernel@vger.kernel.org, Arnd Bergmann Arnd Bergmann Subject: [PATCH v4 1/2] Documentation: Add GPIO reset binding to reset binding documentation Date: Mon, 14 Apr 2014 10:21:48 +0200 Message-Id: <1397463709-19405-1-git-send-email-p.zabel@pengutronix.de> X-Mailer: git-send-email 1.9.1 X-SA-Exim-Connect-IP: 10.1.0.120 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140414_012230_461968_9C719E42 X-CRM114-Status: GOOD ( 13.91 ) X-Spam-Score: -1.0 (-) Cc: Mark Rutland , devicetree@vger.kernel.org, Philipp Zabel , Stephen Warren , kernel@pengutronix.de, Maxime Ripard , linux-arm-kernel@lists.infradead.org, Roger Quadros X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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=-2.9 required=5.0 tests=BAYES_00,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 This patch adds documentation clarifying the reset GPIO bindings most commonly in use (reset-gpios and -reset-gpios properties). Signed-off-by: Philipp Zabel --- Documentation/devicetree/bindings/reset/reset.txt | 26 +++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) diff --git a/Documentation/devicetree/bindings/reset/reset.txt b/Documentation/devicetree/bindings/reset/reset.txt index 31db6ff..51f9e35 100644 --- a/Documentation/devicetree/bindings/reset/reset.txt +++ b/Documentation/devicetree/bindings/reset/reset.txt @@ -2,8 +2,8 @@ This binding is intended to represent the hardware reset signals present internally in most IC (SoC, FPGA, ...) designs. Reset signals for whole -standalone chips are most likely better represented as GPIOs, although there -are likely to be exceptions to this rule. +standalone chips are most likely better represented as GPIOs, ideally using a +common scheme as described below. Hardware blocks typically receive a reset signal. This signal is generated by a reset provider (e.g. power management or clock module) and received by a @@ -56,6 +56,20 @@ reset-names: List of reset signal name strings sorted in the same order as the resets property. Consumers drivers will use reset-names to match reset signal names with reset specifiers. += GPIO Reset consumers = + +For the common case of reset lines controlled by GPIOs, the GPIO binding +documented in devicetree/bindings/gpio/gpio.txt should be used: + +Required properties: +reset-gpios or Reset GPIO using standard GPIO bindings, +-reset-gpios: optionally named to specify the reset line + +Optional properties: +reset-boot-asserted or Boolean. If set, the corresponding reset is +-reset-boot-asserted: initially asserted and should be kept that way + until released by the driver. + For example: device { @@ -65,6 +79,14 @@ For example: This represents a device with a single reset signal named "reset". + device2 { + reset-gpios = <&gpio3 15 GPIO_ACTIVE_LOW>; + reset-boot-asserted; + }; + +This represents a device with a single reset signal, controlled +by an active-low GPIO, which is initally kept in reset. + bus { resets = <&rst 10> <&rst 11> <&rst 12> <&rst 11>; reset-names = "i2s1", "i2s2", "dma", "mixer";