From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philipp Zabel Subject: [PATCH v3 1/2] Documentation: Add GPIO reset binding to reset binding documentation Date: Wed, 8 Jan 2014 12:11:03 +0100 Message-ID: <1389179464-11963-1-git-send-email-p.zabel@pengutronix.de> Return-path: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, Roger Quadros , Mark Rutland , Maxime Ripard , Stephen Warren , Arnd Bergmann , Philipp Zabel List-Id: devicetree@vger.kernel.org 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"; -- 1.8.5.2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html