From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gloria.sntech.de (gloria.sntech.de [185.11.138.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A2C61757EA; Fri, 21 Feb 2025 13:49:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.11.138.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740145744; cv=none; b=j20SGzyn+iKOU6A3qHkca35h5wvrh5qQjsYvJ6MseqQic0k5sKi6E7vPasVr9h1aaEfIqepWL2mmEHH2wYh1lFxpux8mf1wSZRXSZShGTldxznoVzTqv+nOLRRB9WSFTS1xxhtZb0fl2BU6NsUrscvyQPY1ZV/bKUZTAqarR4LQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740145744; c=relaxed/simple; bh=LpD8P8JjpqI/NjmfRrr1AhD28mE8fg5sTAYIzzPCseM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ULIiyJWIhzPxM20hJVfgHx6EUOYkO9zNLb2a3k5bpP0gtX0gdELKGMwrbogUGNTWc6WAo+skOEF5YsuKi1BRtnVRyWQHSsrOcJFqppDOIRT1Zv9Ai1eaMyGDFb+sr3gdZ0K+U6Se+3yZNMzk/Nf9sQOlysmqHL0RPfERNOIFfQg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sntech.de; spf=pass smtp.mailfrom=sntech.de; dkim=pass (2048-bit key) header.d=sntech.de header.i=@sntech.de header.b=EOlMpGf6; arc=none smtp.client-ip=185.11.138.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sntech.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sntech.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sntech.de header.i=@sntech.de header.b="EOlMpGf6" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sntech.de; s=gloria202408; h=Content-Type:Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=4PA6AoUOc58pLObnZDeDC9vxCiLpRKUfWVTweUqJLBc=; b=EOlMpGf6Z4x3XKn2jeJ+0MxWRx o4RGyPM2SqMWVeWo83VUGe9BS8ebFNLcac3bio+6ZsUtXIigNT9XgaGxEChymTXGdSvPQS8tqCfQt X0gsEgE4dGAXxl/u7TtRsNUJisMPbhpX5iQLoQNsFVNr31JwYJIK2YPw/g/MWChTPHGMQFNpOjayF o6D/PVRpFCklSoWC+PYXbLM3sMq4rx9peHg1bArSQX0sUeU+7J+0iRH7LZ4EzFAViLTQFJVA7Fm3C io3Tbp2qETu9gobdkTgfO8azcy8/TiUc4kNSSmhuiSUYvDPaFUdhZFwBYzCsF1IjCT7DHbCM+FpBH iaieQ5wg==; Received: from i53875a87.versanet.de ([83.135.90.135] helo=diego.localnet) by gloria.sntech.de with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1tlTOh-0004r8-VJ; Fri, 21 Feb 2025 14:48:56 +0100 From: Heiko =?UTF-8?B?U3TDvGJuZXI=?= To: Linus Walleij , Bartosz Golaszewski , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Laurent Pinchart , Quentin Schulz Cc: linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Quentin Schulz Subject: Re: [PATCH v2 2/2] gpio: pcf857x: add support for reset-gpios on (most) PCA967x Date: Fri, 21 Feb 2025 14:48:55 +0100 Message-ID: <1947442.eGJsNajkDb@diego> In-Reply-To: <20250221-pca976x-reset-driver-v2-2-a2bcb9fdc256@cherry.de> References: <20250221-pca976x-reset-driver-v2-0-a2bcb9fdc256@cherry.de> <20250221-pca976x-reset-driver-v2-2-a2bcb9fdc256@cherry.de> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Am Freitag, 21. Februar 2025, 11:14:27 MEZ schrieb Quentin Schulz: > From: Quentin Schulz > > The PCA9670, PCA9671, PCA9672 and PCA9673 all have a RESETN input pin > that is used to reset the I2C GPIO expander. > > One needs to hold this pin low for at least 4us and the reset should be > finished after about 100us according to the datasheet[1]. Once the reset > is done, the "registers and I2C-bus state machine will be held in their > default state until the RESET input is once again HIGH.". > > Because the logic is reset, the latch values eventually provided in the > Device Tree via lines-initial-states property are inapplicable so they > are simply ignored if a reset GPIO is provided. > > [1] https://www.nxp.com/docs/en/data-sheet/PCA9670.pdf 8.5 and fig 22. > > Tested-by: Heiko Stuebner # RK3588 Tiger Haikou Video Demo > Signed-off-by: Quentin Schulz Reviewed-by: Heiko Stuebner