From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 ED92C24B249; Sat, 11 Jan 2025 11:00:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736593244; cv=none; b=oYpQBhPc8Q1UO8WJi2lW6jxKJf4XYTp+eQjq1KH6+noD5iyfp1F0SxAr6BMLntm/ziOwy7iV6IrQNrW6qORSGsXmdRD9d/SH9uCNTC6Pe6ms2zIneGlGjGrFgRsIoDl1LO+Zu5UE7dWNeB3xsU1HRaBkLPDLRzhaLhm3rWkjC7w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736593244; c=relaxed/simple; bh=8iT/gzGH38ArVzH1eYk/cuM0mceP6qrn9tr57pN3r7Y=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WLc49N+NC52RYujcDDSLuO+D+yVQaZLu02vNvW6gzhMAYbxSZV1FBj48fIwPeYlIpXFieJhsri1dk5lt6uPhNtWE1TKstrZREqQXgQb/e0XGrrhUaIpUOCaDeS6i6jR959o4PCFB4KDg156zFeKZ7Voiv2KL0xI/cAYx/dWTp1Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mDk7p+jC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mDk7p+jC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96A61C4CED2; Sat, 11 Jan 2025 11:00:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736593243; bh=8iT/gzGH38ArVzH1eYk/cuM0mceP6qrn9tr57pN3r7Y=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=mDk7p+jCadbjEWZqHzIDIjFruNvZr2JXbsitSaWKUDNdcoBGB8pVJFBfjgomCz7yA aSSxZVqnoZ7NRsYT+3cg8R/f5p56Ww34dVacRARGL9yAEbSxy0wa0jmccXBOUBJMH7 6iBzQwwEgFetCIq1w1HCE1JA4S74MrF0vET7014A66t5x45H7nMtEGX0W51MieNTTf j8EY5lk1GjAJ4MVzVIXRzS/wsmqfv0MLhZEO1Zm8FtYC2mCpdnOb843gfbJ7GM3y7c 7EonyqSVPPsQsYhlAhDcCWdbqhIQCVCm/9vaSK0dEaOJsarj0wYm1sETFBhaIF5cuU yFFU1ciiDuhTA== Message-ID: <9bb482aa-a392-45c2-a21f-d08e5ce3a6e0@kernel.org> Date: Sat, 11 Jan 2025 12:00:37 +0100 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 0/2] gpio: 74x164: use a compatible fallback and don't extend the driver To: Bartosz Golaszewski , Geert Uytterhoeven Cc: =?UTF-8?B?Q3PDs2vDoXMgQmVuY2U=?= , Linus Walleij , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Maxime Ripard , =?UTF-8?B?SiAuIE5ldXNjaMOkZmVy?= , linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski References: <20250110130025.55004-1-brgl@bgdev.pl> Content-Language: en-US From: Krzysztof Kozlowski Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/01/2025 15:14, Bartosz Golaszewski wrote: >> At24 EEPROMs differ from '595 shift registers in that they provide an >> API with multiple commands, and some commands or parameter bits may >> differ among different implementations (but usually these differences >> are called quirks). >> >> All '595 (I'm deliberately writing it like that) shift registers >> should be 100% compatible, modulo some electrical specifications >> (voltage levels, maximum speed, power consumption, ...). >> >> Interestingly, the driver is called gpio-74x164.c, while no '164 >> compatible value is present. Most important difference is that the >> '164 lacks the output latch, which is used as chip-select with SPI[1]. >> >>>> I'm especially against introducing a new, vendor-specific (On Semi, in >>>> this case) name; if we really want to introduce a new compatible, at >>>> least make it as generic as possible, i.e. `generic,74x595`, or even >>>> `generic,spi-shift-register-output`. >>> >>> If anything, that would have to be the fallback that the driver knows. >>> The first string in the compatible property has to have an actual >>> vendor (I think, I'll let DT maintainers correct me). >> >> For the inverse operation (parallel in, serial out), there's just >> "pisosr-gpio". >> > > Ok, I admit I don't know the correct next step. I'll wait for > Krzysztof, Rob or Conor to chime in (on the subject of representing > reality - the actual manufacturer - in DTS) and then possibly just > remove patches 1-2 from my tree. > Well, folks, I don't know the exact device, so maybe there is no point in a new compatible if there is a claim all devices have same interface and documenting all of them would result in 1000 redundant compatibles... but OTOH, that's what we still do with jedec,spi and at24, so if we can add specific compatibles for these, we can do same also here. Best regards, Krzysztof