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 6F0531DFF7; Sat, 28 Sep 2024 12:53:49 +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=1727528030; cv=none; b=jI0svOpizkPQukU4clsencE9OLewCnT52ghDYodQCi1jQTnW9VomAtHqnTp/j+jTwO2WeS72PbypJEDA/1OXUGbnje3jlBIvmt9+meO2bSjJc4DSnZZv4jf2OZ1Jlzy8AIYiqUx68kp1rpJB1o4HwCX58CJp/qA+vwggpLuf9nA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727528030; c=relaxed/simple; bh=lXQwcL/7NWG7ExGqevrmOkKKrfoWwNZ/kwtDJvmkYvQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jTfKgWyvaYAAyGJyk2QXJjLC8c3+NbG5uSTHQ84cSUKktuZ2IvEHTay1dH1gV1f6aEWwtfLMqyN/7pSlV4ppyAqbQc9tRitqHnISPuuOR20UH+eTzcJ3hnHiOVRV5MBsrP4QkSl1DCD5sYMIXlRKu2PhYqtsn8xp0nSst2KgGTo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SuHUK8lb; 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="SuHUK8lb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B9D4C4CEC3; Sat, 28 Sep 2024 12:53:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727528029; bh=lXQwcL/7NWG7ExGqevrmOkKKrfoWwNZ/kwtDJvmkYvQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=SuHUK8lbW1G+8la6edvfe1a9KQFgdB/phyRrc9AvoHruEPkerycv8w5/zwiZ4IH/v sY8rO13eS7SYdBeKeMQHdq0k5ZsG62R4JpT+qzlKbP1gdYVyenRVzbhghQsW1uC1E7 Xt4zMOcCBf6loR6VzyLYKDdUubT+dlIQSDbCGMkqG6/93XoS9AFBSJIKRY8FqBkrfK b6mNJ46yKcIaJafjXiskBs0VlCIaewv+CfdDZdI23gsLcIiv74EKQX6snyMQngpvoz itC9UT0qzRIR6XL+HO+FJ2mrt4gdpQY+JF8qLf+pB5mpppAosLHy4KA3GvTA1pyg8+ 9zzpk4Tp51eEw== Message-ID: Date: Sat, 28 Sep 2024 14:53:44 +0200 Precedence: bulk X-Mailing-List: linux-fpga@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] dt-bindings: fpga: Add Efinix serial SPI programming bindings To: Ian Dannapel Cc: mdf@kernel.org, hao.wu@intel.com, yilun.xu@intel.com, trix@redhat.com, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, neil.armstrong@linaro.org, heiko.stuebner@cherry.de, rafal@milecki.pl, linus.walleij@linaro.org, linux-fpga@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20240927141445.157234-1-iansdannapel@gmail.com> <20240927141445.157234-2-iansdannapel@gmail.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 28/09/2024 14:33, Ian Dannapel wrote: >>>> >>>>> + >>>>> + spi-cpha: true >>>>> + >>>>> + spi-cpol: true >>>>> + >>>>> + spi-max-frequency: >>>>> + maximum: 25000000 >>>>> + >>>>> + reg: >>>>> + maxItems: 1 >>>>> + >>>>> + creset-gpios: >>>> >>>> reset-gpios >>>> >>>> Do not invent own properties. >>>> >>>>> + description: >>>>> + reset and re-configuration trigger pin (low active) >>>>> + maxItems: 1 >>>>> + >>>>> + cs-gpios: >>>>> + description: >>>>> + chip-select pin (low active) >>>> >>>> Eee? That's a property of controller, not child. Aren't you duplicating >>>> existing controller property? >>> This device uses this pin in combination with the reset to enter the >>> programming mode. Also, the driver must guarantee that the pin is >> >> Isn't this the same on every SPI device? > Yes, but I was not very clear. In this case the pin must be hold > active including entering the programming mode. And if the controller Just like every CS, no? The only difference is that you must send entire programming sequence without releasing the CS. > transfers the data in bursts, the pin is also not allowed to go > inactive between transfer bursts. >> >>> active for the whole transfer process, including ending dummy bits. >>> This is why I added a warning to NOT use this driver with other >>> devices on the same bus. >> >> Not really related. None of this grants exception from duplicating >> controller's property. >> >> How do you think it will even work in Linux, if same GPIO is requested >> twice (imagine controller also has it)? Till now, this would be -EBUSY. > I expected that the controller is not able request the same gpio. From > the controller point of view, it is a device that does not have a chip > select. Not sure if the controller would be able to get to this gpio > if it is not explicitly given. But it could be given. Don't think only about your case. Your description earlier clearly suggests it is CS. Description here suggests it is not a CS. No clue then. >> >> But regardless of implementation, I still do not understand why do you >> need duplicate same chip-select. Maybe just the naming is the confusion, >> dunno. > This could be an option to make the difference to a "real chip-select" > clear, but it would drift away from the datasheet naming. Eg, > prog-select? Please go back to datasheet. Which pin is this? CS, yes or not? If not, then which other pin is CS? Best regards, Krzysztof