From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f53.google.com (mail-wr1-f53.google.com [209.85.221.53]) (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 BDE8F1F3BB6 for ; Wed, 26 Mar 2025 14:48:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743000536; cv=none; b=q75sQV0FhICHkjnvuaxlQbQvt9uTqmnpElAjLIs2iKLwgSVXZWT7awBNIqUUNCnunl9eKs/TVq9afQYBVkY24lefP6SSfKljcj1dE4f9/11T2iASXicF3TReTHcq012XOffV5VCpzLAE7iWX/HJBqX0fl37FXSFx7TCSnPBndQw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743000536; c=relaxed/simple; bh=V9OPN9ZbeHaXk5j2cNowUnTpyiTZNQfQrH6Jh2QA1EA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=XL5ZI1HvlUzX3uQjugYvaK7xiSx7nLVkhsir6+NwdB6MgVX2uRL3qx5R9wXVRsXwzbokAmBbNdgEykaxf8Wh7I1KgRENn9ujQesAo+mG1mdR8dc5ChqKo00q7IMJ5QAQvGay2RCANscPLX11LNgkrtA0jhiJScRVO4++M16hhzA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org; spf=pass smtp.mailfrom=linaro.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b=iKLUqt1R; arc=none smtp.client-ip=209.85.221.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linaro.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="iKLUqt1R" Received: by mail-wr1-f53.google.com with SMTP id ffacd0b85a97d-3913fdd0120so3847473f8f.0 for ; Wed, 26 Mar 2025 07:48:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1743000533; x=1743605333; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=k7F63w5WbLJMRPxYzdb7qfC13R+bJpmQhvYwda9HcaI=; b=iKLUqt1R0jYGBxutzkmCFp3S/hyd2nI/oAS5cvHC4Q3r8YLPrxaMMk80CB0cADdfei y3GH4py+9YotW7Gb7TGwKSyO5xR9gAHL7yU/NJEo2/xXd0TOSxzKkMu33mjCSANPKxf3 q6/NV2O5sf3qKitahjyy2QNCCpU/Q52SK95YDpIAivVYwjFebMhzB0lFwjnWFZDWLDvb cIsSskN50bBS8sakBGAUbPGWiIa9bml6u9bPU23c8iyw9ZCAk7ADX1bDpxXF7hYILyai ijtnVlfOcDrPIYV2xltXGIGjki4wVwd+KXKHvOBchvAtBnsVt1HBA8kYQ69UH9eO/foS nbNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1743000533; x=1743605333; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=k7F63w5WbLJMRPxYzdb7qfC13R+bJpmQhvYwda9HcaI=; b=MW9hTbI8coi50PUo1LSYI162cZUmsghR0E4HY2LtMoZeXjqkOj5VsTNplvJrGnWe7n YPL8ILU9+s8aJZVK3XjL3tO2I+zAqlwRCNJoiMTpmtfYhDLsunnCBjA3uFyvc0vBamH/ T91LLc4Rgs1pnJn37diZ7w55zY641YK67eI0fy6P03zXnJeqN1PosD7CENDjlZ8F+AFE 8BFfaO8vBw1bYb6F/T9v278Ckl33jOGW8Q7+dEGfsVPnewPUpsfKfQtyz5tes6QFh3M1 a6iqapkXFsn/Jrv/WJNZj5i2xWlUt9i2zp3wD4Fb4L8Giw4VVqXUngLpqCadGXhVj6NP sRiw== X-Forwarded-Encrypted: i=1; AJvYcCVaeeOpImoqZQG9zSSvP2nJavI5ZWVJ+qEzBhN/EcbADwVZ76Ir8uzuUzzpmhjPd7pK//ho+NxKEYkKa4s=@vger.kernel.org X-Gm-Message-State: AOJu0YwiSwxIFx0UXqG/UeZQOuyIPM9G6vIR22E75IF9xztZfSfnUpvH edYabsiiXiAGTVivQB8397oLnOu5MDYZR1a1m47IKD+6pUwwXk2NNtLYa25js7E= X-Gm-Gg: ASbGnctQvTJPKJJsk2zfJOMtRaTey1S0YLep2aAHscmPm1eXmWuDNSACF1EfJcXpFJj d8ibJOIBh2GSKo2Bw3p83gZzXvHufFVOe8odN9n14T9ZwwDiPRp/fHJJ4lUXPwtG1uzCzqkmE6R XEk5GnDuz4LUjXesR8Ed4fO0vBqeXj5YNWu/JtZewZ9OLU7uqiZkXBkvatyk2Y9U8OU3cn6/6yD 0kB8oWTPongBWjLSVyBA71RbS6pCgyQK8vTVkdZMZOaV8AECKIL1vRptJvo0liRjIVqmse2dCNh k6iFKpjaPYg89DCY05DqFi+S86JmBcUiP+MN7GeEyxvm3gVrAuK/rpA= X-Google-Smtp-Source: AGHT+IG054URsTL05MtZIrzYoZ2nRY1iaq/5fvUAR6DYti36wbbvJ51FuVkhLdk4NeF87evX5MRxvw== X-Received: by 2002:a05:6000:1864:b0:391:10c5:d1ab with SMTP id ffacd0b85a97d-3997f8f61d0mr17080409f8f.5.1743000532936; Wed, 26 Mar 2025 07:48:52 -0700 (PDT) Received: from [192.168.0.251] ([79.115.63.206]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3997f9ef1f7sm16901316f8f.82.2025.03.26.07.48.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 26 Mar 2025 07:48:52 -0700 (PDT) Message-ID: Date: Wed, 26 Mar 2025 14:48:50 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V1] spi: Add support for Double Transfer Rate (DTR) mode To: Mukesh Kumar Savaliya , Mark Brown Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, andersson@kernel.org, konradybcio@kernel.org References: <20250326083954.3338597-1-quic_msavaliy@quicinc.com> <40db39ef-7ef3-4720-9c85-ccfe1c11c299@sirena.org.uk> Content-Language: en-US From: Tudor Ambarus In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 3/26/25 2:25 PM, Mukesh Kumar Savaliya wrote: > Hi Mark, thanks for your comment. > > On 3/26/2025 6:34 PM, Mark Brown wrote: >> On Wed, Mar 26, 2025 at 02:09:54PM +0530, Mukesh Kumar Savaliya wrote: >> >>> This change introduces a new field `dtr_mode` in the `spi_transfer` >>> structure. The `dtr_mode` field allows protocol drivers to indicate if >>> Double Transfer Rate (DTR) mode is supported for a given transfer. When >>> `dtr_mode` is set to true, the SPI controller will use DTR mode >>> otherwise, it will default to single transfer mode. >> >>> The QSPI controller driver uses this flag and configures single or >>> double >>> transfer rate using the controller register. >> >> We should have a flag in the controller indicating if it supports this, >> and code in the core which returns an error if a driver attempts to use >> it when the controller doesn't support it. > Have added below in spi.h which can be set by client and controller > driver should be using it to decide mode. > > + bool        dtr_mode; > > since default it's false, should continue with SDR. > I believe for QSPI, it supports SDR or DDR, but it's not applicable to > standard SPI right ? So not sure in which case we should return an error ? > Please check how spimem is dealing with DTR, same ideas shall be applied for spi transfers. Cheers, ta