From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f49.google.com (mail-wr1-f49.google.com [209.85.221.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3493728EA72 for ; Sat, 24 Jan 2026 12:36:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.49 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769258207; cv=none; b=TDktA7PZ9APLaGu/as22fgrmj+XtFBCPkGXSc9yYgxLbnI1qZuWI4+7nDJte65f6ovq1X8KhzgTkI43TfSu7ljzJwDb8JA+mSssFfk4k/LYjAkgJpWtxoskZxZZW/MCB5U5hIH6DBheB2D/tDTyPjTBQkAuzfOINn0Wmp9Ofc9g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769258207; c=relaxed/simple; bh=2lpZPiehnZVWy67SwNKoHY2awngWTM8se8vqxPxB49s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QtOhDpldJfKepVrIk4hIo+4HN/L3KCKaySx4Igm6BatpD2EWz3gtPWz9NdpRIx54Oiy/uiZxkX09X4p3wWSUFYeVXMOMhm4b14bHTcxk9VLaY0JJO3EwGf0gNus0ZABhYClWz3JCZh1Lg9+5iOAG1AHVnOX2oL/b760pjIxvOMI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=ZKXZuKU6; arc=none smtp.client-ip=209.85.221.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ZKXZuKU6" Received: by mail-wr1-f49.google.com with SMTP id ffacd0b85a97d-42fb2314f52so1716292f8f.0 for ; Sat, 24 Jan 2026 04:36:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1769258204; x=1769863004; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=aWxFjlQ15iLHcZ2sWOA5/KipFAdTrRSE3rE8bBRoPNA=; b=ZKXZuKU6H3gpgJsBv4nBKoSRZurn8Uq84zCD5msjjPeLSfiZHak/zkvW5uVpmUeVvu IQ7b6BTrwj2w9L8U1cdLDndX2TzL/nBRBVaPPsIn8I0I/BC+UX1pSiEKnHgOzQiv3Kqr 2Dtd7OglaljVFT4EHPwI70g2PDFnu58bcaWX3Kf6JXerqh4rxnVtsCzr7ljxQH6OVjNE So2h+8zVCiz7V+tb9gMd9NOUm0WTkWZDP1zmhJnqmKNTG7AzfDCANQk7mxiXsXVVb87s 1WGs3mc42WxRCY8yXugGy/O5l7bEn0cywRpujac9wUrOamSS8ii1q7RU9D8RhPdaqDFw xGUg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769258204; x=1769863004; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=aWxFjlQ15iLHcZ2sWOA5/KipFAdTrRSE3rE8bBRoPNA=; b=BoPlPrfsmnnyRuYHY1bFUn6MzKKHSlWOT8p+1B0+2i11o4FfoehRlp2ygLKCO5+n+2 ZxXqecm6qmRkuY9zgWsIfdGhnfTtfvCBX6ermW7EgVY8RUv1pPp2XFrVgjaKsGx8/iFQ 2H762Vu/ir91+JMM2CqGzsG/8MN5ZRPUA6gjLPNYcHcxvhb4pM8KY/CsP6JB0/unLyAN DkLvv7WExCQsJSyzfuVzopK2sLrZnjpsgUXbeo7n410YlakcGKKoJFJmCxtz5wgTeVyi YO/OUC9sV826pC4/7MBWUxlitEXS+kkE+7cnEUT8jRpcOJWFZXtl5SEz8ipOC9pQWJ7T ZsIQ== X-Forwarded-Encrypted: i=1; AJvYcCVpAdZzzbuyVaxA3g5AiYSeCPW/3tLwME40Z6bF++puMuJdH0AeY9Q/52pVnpijZPTSZwMen2WK89mZ@vger.kernel.org X-Gm-Message-State: AOJu0YyneN6eLd5r+EgFUhu5LeGmDXMp6iV8BpRjF0IPhxVcC6uzybTv ict6vPuNLOkyESWm5PqHg5s9H4iPVBrz8jaotMp9J2zYTQ8UIY62UdyP X-Gm-Gg: AZuq6aKevssmb28IC0P7ihJJo6kfHcMdrTi8k8pSaLU0rgGz+emUQRQw9SMra7+BQDm xgwWKvG+eUQZBuAQJqNSNAJoVhUJqVQLfo1zoX1L1wzzHNILOXo+zS5YddX7/+AgcGADKTJiIby ytpcbV+kDQ9evrRPwed2trkZaPNHSqH4iR+aVD0AvGk1ibZyRWV9ZxvCeRnYwmoSQemosAf72fj ogS4maKnmZSnllRrBY38oGlDubyLNhiyLQU2TKrpfQPxbKPoF7gQuZkUxSThordOuJYlB+KFP5F eGM8AqOBY2PTUYybNOx4rZugBJSGaxYOPhMoTCXWYb+UtMk9FM0c1akweOx0udkOsMiIfvxVUuf wCL3uIofA88YwHWXD4jlOORzdqmB5QzNQQGDtzQL/koue9D/Aw5+x6XtBoIOoDA98pumf8KNM5Y eroVJjergEK7OK8fKAiUQ9tof10WKi343gt3IP33XEchyobqh1hlJDy8BlJgOmtBj2 X-Received: by 2002:a05:6000:1847:b0:435:9756:d4c4 with SMTP id ffacd0b85a97d-435b15d6927mr9998528f8f.17.1769258204232; Sat, 24 Jan 2026 04:36:44 -0800 (PST) Received: from localhost (brnt-04-b2-v4wan-170138-cust2432.vm7.cable.virginm.net. [94.175.9.129]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-435b1f7c9cesm14772613f8f.41.2026.01.24.04.36.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 24 Jan 2026 04:36:42 -0800 (PST) Date: Sat, 24 Jan 2026 12:36:42 +0000 From: Stafford Horne To: Gary Lau Cc: linusw , linux-kernel , linux-openrisc , devicetree , robh , krzk+dt , conor+dt , geert+renesas , "krzysztof.kozlowski" , brgl , linux-gpio Subject: Re: [PATCH v6 1/6] dt-bindings: gpio-mmio: Correct opencores GPIO Message-ID: References: Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Fri, Jan 23, 2026 at 10:18:04PM +0800, Gary Lau wrote: > Hi Stafford, > > I should clarify my setup: I'm using hardware address translation to make the > OpenCores 8-bit GPIO appear as 32-bit to the CPU. Specifically: > > 1. Address translation: The CPU's 32-bit addresses are right-shifted by 2 bits >    (adr_i[2] in Verilog), so each 32-bit CPU access maps to the correct 8-bit >    OpenCores register. > > 2. Data width adaptation: Only dat_i[7:0] and dat_o[7:0] are connected, so >    32-bit writes are truncated to 8-bit, and reads are zero-extended. > > This hardware wrapper makes brcm,bcm6345-gpio driver "work" with my OpenCores > GPIO, but it's really a hardware-level compatibility layer, not true software > compatibility. > > So you're absolutely right that the native opencores,gpio isn't compatible > with brcm,bcm6345-gpio. My setup works because of custom hardware translation, > not because the IP cores are compatible. Thanks Gary for testing. -Stafford