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 ED713C2FD; Thu, 5 Sep 2024 16:52:23 +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=1725555146; cv=none; b=Y/TXixOVQNMENEIN01qMUGpMIDy2BSvHnB8mEMTUGcyYHMk2+EXC5kjxTxf5VmnxlavMHiXbwBgSCwOsydT3+7uZlPSooclPE0yAPGJtPjs56jGnA0YkM+fvAE8bJM3CuY+H80kqrNUsVi9eiZcRDA5ZNHEOCn9fMeRTwTgqBps= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725555146; c=relaxed/simple; bh=LxreSBk46ePe4SK89Oq0or2qu57zLm/XmRM6LSpM+D4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=KBnAwZUyUt2uDOwBJHEjgXt8h509ES0hzYy0D8lPw0C17K2QptsSm7/0vNBzhHv/beTAjmoNPXcvmI5D96+a6GJxhahxgSFcBk7QTm24c1h9BjNGSQMQILl4ucgnQjgiW8Z9ovHUAxjD8YBc7xMoIt7L67LhmEisDRK9IdNbUsQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aJiK/RmV; 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="aJiK/RmV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9AB2FC4CEC3; Thu, 5 Sep 2024 16:52:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725555143; bh=LxreSBk46ePe4SK89Oq0or2qu57zLm/XmRM6LSpM+D4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=aJiK/RmVZU+4QKnS20PevtZxI9Ao5l8kyPyrEFRfP5OJUiANjObzveTqFVMZvBfaq WvBZ+sESik2xeJo7HJwHV0YtQmU/k+E9sevdItiN3gY+oLQvNT6DIzErhTFmAtRfvW Z3Th9wsbWepCEbJIn8XbaTM2jgGsDsmD8igQpy4bYxlw1YLVMkgk1IHrAZ5ESpS4oO bGLgGWuO0oL57SU0Ub3Ntu7DwZK3eT0dYB3UuIjeRCvdcJ/zI6p6vNbBkpIANesZa+ otXUzG3BSdj36YMneV4hn7uLwaEtsfN2PluWHfEebPoVRWvofMfzhvbjttQkItfin6 Z02VSAPBtn/eA== Message-ID: Date: Thu, 5 Sep 2024 18:52:10 +0200 Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 08/11] misc: rp1: RaspberryPi RP1 misc driver To: Andrea della Porta Cc: Michael Turquette , Stephen Boyd , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Florian Fainelli , Broadcom internal kernel review list , Linus Walleij , Catalin Marinas , Will Deacon , Derek Kiernan , Dragan Cvetic , Arnd Bergmann , Greg Kroah-Hartman , Nicolas Ferre , Claudiu Beznea , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Saravana Kannan , Bjorn Helgaas , linux-clk@vger.kernel.org, devicetree@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, linux-arch@vger.kernel.org, Lee Jones , Andrew Lunn , Stefan Wahren References: <5954e4dccc0e158cf434d2c281ad57120538409b.1724159867.git.andrea.porta@suse.com> <39735704-ae94-4ff8-bf4d-d2638b046c8e@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; keydata= xsFNBFVDQq4BEAC6KeLOfFsAvFMBsrCrJ2bCalhPv5+KQF2PS2+iwZI8BpRZoV+Bd5kWvN79 cFgcqTTuNHjAvxtUG8pQgGTHAObYs6xeYJtjUH0ZX6ndJ33FJYf5V3yXqqjcZ30FgHzJCFUu JMp7PSyMPzpUXfU12yfcRYVEMQrmplNZssmYhiTeVicuOOypWugZKVLGNm0IweVCaZ/DJDIH gNbpvVwjcKYrx85m9cBVEBUGaQP6AT7qlVCkrf50v8bofSIyVa2xmubbAwwFA1oxoOusjPIE J3iadrwpFvsZjF5uHAKS+7wHLoW9hVzOnLbX6ajk5Hf8Pb1m+VH/E8bPBNNYKkfTtypTDUCj NYcd27tjnXfG+SDs/EXNUAIRefCyvaRG7oRYF3Ec+2RgQDRnmmjCjoQNbFrJvJkFHlPeHaeS BosGY+XWKydnmsfY7SSnjAzLUGAFhLd/XDVpb1Een2XucPpKvt9ORF+48gy12FA5GduRLhQU vK4tU7ojoem/G23PcowM1CwPurC8sAVsQb9KmwTGh7rVz3ks3w/zfGBy3+WmLg++C2Wct6nM Pd8/6CBVjEWqD06/RjI2AnjIq5fSEH/BIfXXfC68nMp9BZoy3So4ZsbOlBmtAPvMYX6U8VwD TNeBxJu5Ex0Izf1NV9CzC3nNaFUYOY8KfN01X5SExAoVTr09ewARAQABzSVLcnp5c3p0b2Yg S296bG93c2tpIDxrcnprQGtlcm5lbC5vcmc+wsGVBBMBCgA/AhsDBgsJCAcDAgYVCAIJCgsE FgIDAQIeAQIXgBYhBJvQfg4MUfjVlne3VBuTQ307QWKbBQJgPO8PBQkUX63hAAoJEBuTQ307 QWKbBn8P+QFxwl7pDsAKR1InemMAmuykCHl+XgC0LDqrsWhAH5TYeTVXGSyDsuZjHvj+FRP+ gZaEIYSw2Yf0e91U9HXo3RYhEwSmxUQ4Fjhc9qAwGKVPQf6YuQ5yy6pzI8brcKmHHOGrB3tP /MODPt81M1zpograAC2WTDzkICfHKj8LpXp45PylD99J9q0Y+gb04CG5/wXs+1hJy/dz0tYy iua4nCuSRbxnSHKBS5vvjosWWjWQXsRKd+zzXp6kfRHHpzJkhRwF6ArXi4XnQ+REnoTfM5Fk VmVmSQ3yFKKePEzoIriT1b2sXO0g5QXOAvFqB65LZjXG9jGJoVG6ZJrUV1MVK8vamKoVbUEe 0NlLl/tX96HLowHHoKhxEsbFzGzKiFLh7hyboTpy2whdonkDxpnv/H8wE9M3VW/fPgnL2nPe xaBLqyHxy9hA9JrZvxg3IQ61x7rtBWBUQPmEaK0azW+l3ysiNpBhISkZrsW3ZUdknWu87nh6 eTB7mR7xBcVxnomxWwJI4B0wuMwCPdgbV6YDUKCuSgRMUEiVry10xd9KLypR9Vfyn1AhROrq AubRPVeJBf9zR5UW1trJNfwVt3XmbHX50HCcHdEdCKiT9O+FiEcahIaWh9lihvO0ci0TtVGZ MCEtaCE80Q3Ma9RdHYB3uVF930jwquplFLNF+IBCn5JRzsFNBFVDXDQBEADNkrQYSREUL4D3 Gws46JEoZ9HEQOKtkrwjrzlw/tCmqVzERRPvz2Xg8n7+HRCrgqnodIYoUh5WsU84N03KlLue MNsWLJBvBaubYN4JuJIdRr4dS4oyF1/fQAQPHh8Thpiz0SAZFx6iWKB7Qrz3OrGCjTPcW6ei OMheesVS5hxietSmlin+SilmIAPZHx7n242u6kdHOh+/SyLImKn/dh9RzatVpUKbv34eP1wA GldWsRxbf3WP9pFNObSzI/Bo3kA89Xx2rO2roC+Gq4LeHvo7ptzcLcrqaHUAcZ3CgFG88CnA 6z6lBZn0WyewEcPOPdcUB2Q7D/NiUY+HDiV99rAYPJztjeTrBSTnHeSBPb+qn5ZZGQwIdUW9 YegxWKvXXHTwB5eMzo/RB6vffwqcnHDoe0q7VgzRRZJwpi6aMIXLfeWZ5Wrwaw2zldFuO4Dt 91pFzBSOIpeMtfgb/Pfe/a1WJ/GgaIRIBE+NUqckM+3zJHGmVPqJP/h2Iwv6nw8U+7Yyl6gU BLHFTg2hYnLFJI4Xjg+AX1hHFVKmvl3VBHIsBv0oDcsQWXqY+NaFahT0lRPjYtrTa1v3tem/ JoFzZ4B0p27K+qQCF2R96hVvuEyjzBmdq2esyE6zIqftdo4MOJho8uctOiWbwNNq2U9pPWmu 4vXVFBYIGmpyNPYzRm0QPwARAQABwsF8BBgBCgAmAhsMFiEEm9B+DgxR+NWWd7dUG5NDfTtB YpsFAmA872oFCRRflLYACgkQG5NDfTtBYpvScw/9GrqBrVLuJoJ52qBBKUBDo4E+5fU1bjt0 Gv0nh/hNJuecuRY6aemU6HOPNc2t8QHMSvwbSF+Vp9ZkOvrM36yUOufctoqON+wXrliEY0J4 ksR89ZILRRAold9Mh0YDqEJc1HmuxYLJ7lnbLYH1oui8bLbMBM8S2Uo9RKqV2GROLi44enVt vdrDvo+CxKj2K+d4cleCNiz5qbTxPUW/cgkwG0lJc4I4sso7l4XMDKn95c7JtNsuzqKvhEVS oic5by3fbUnuI0cemeizF4QdtX2uQxrP7RwHFBd+YUia7zCcz0//rv6FZmAxWZGy5arNl6Vm lQqNo7/Poh8WWfRS+xegBxc6hBXahpyUKphAKYkah+m+I0QToCfnGKnPqyYIMDEHCS/RfqA5 t8F+O56+oyLBAeWX7XcmyM6TGeVfb+OZVMJnZzK0s2VYAuI0Rl87FBFYgULdgqKV7R7WHzwD uZwJCLykjad45hsWcOGk3OcaAGQS6NDlfhM6O9aYNwGL6tGt/6BkRikNOs7VDEa4/HlbaSJo 7FgndGw1kWmkeL6oQh7wBvYll2buKod4qYntmNKEicoHGU+x91Gcan8mCoqhJkbqrL7+nXG2 5Q/GS5M9RFWS+nYyJh+c3OcfKqVcZQNANItt7+ULzdNJuhvTRRdC3g9hmCEuNSr+CLMdnRBY fv0= In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 05/09/2024 18:33, Andrea della Porta wrote: > Hi Krzysztof, > > On 20:27 Tue 03 Sep , Krzysztof Kozlowski wrote: >> On 03/09/2024 17:15, Andrea della Porta wrote: >>>>>>> + >>>>>>> + rp1_clocks: clocks@c040018000 { >>>>>> >>>>>> Why do you mix MMIO with non-MMIO nodes? This really does not look >>>>>> correct. >>>>>> >>>>> >>>>> Right. This is already under discussion here: >>>>> https://lore.kernel.org/all/ZtBzis5CzQMm8loh@apocalypse/ >>>>> >>>>> IIUC you proposed to instantiate the non-MMIO nodes (the three clocks) by >>>>> using CLK_OF_DECLARE. >>>> >>>> Depends. Where are these clocks? Naming suggests they might not be even >>>> part of this device. But if these are part of the device, then why this >>>> is not a clock controller (if they are controllable) or even removed >>>> (because we do not represent internal clock tree in DTS). >>> >>> xosc is a crystal connected to the oscillator input of the RP1, so I would >>> consider it an external fixed-clock. If we were in the entire dts, I would have >>> put it in root under /clocks node, but here we're in the dtbo so I'm not sure >>> where else should I put it. >> >> But physically, on which PCB, where is this clock located? > > xosc is a crystal, feeding the reference clock oscillator input pins of the RP1, > please see page 12 of the following document: > https://datasheets.raspberrypi.com/rp1/rp1-peripherals.pdf That's not the answer. Where is it physically located? > On Rpi5, the PCB is the very same as the one on which the BCM2712 (SoC) and RP1 > are soldered. Would you consider it external (since the crystal is outside the RP1) > or internal (since the oscillator feeded by the crystal is inside the RP1)? So it is on RPi 5 board? Just like every other SoC and every other vendor? Then just like every other SoC and every other vendor it is in board DTS file. > >> >>> >>> Regarding pclk and hclk, I'm still trying to understand where they come from. >>> If they are external clocks (since they are fixed-clock too), they should be >>> in the same node as xosc. CLK_OF_DECLARE does not seem to fit here because >> >> There is no such node as "/clocks" so do not focus on that. That's just >> placeholder but useless and it is inconsistent with other cases (e.g. >> regulators). > > Fine, I beleve that the root node would be okay then, or some other carefully named > node in root, if the clock is not internal to any chip. > >> >> If this is external oscillator then it is not part of RP1 and you cannot >> put it inside just to satisfy your drivers. > > Ack. > >> >>> there's no special management of these clocks, so no new clock definition is >>> needed. >> >>> If they are internal tree, I cannot simply get rid of them because rp1_eth node >>> references these two clocks (see clocks property), so they must be decalred >>> somewhere. Any hint about this?. >>> >> >> Describe the hardware. Show the diagram or schematics where is which device. > > Unfortunately I don't have the documentation (schematics or other info) about > how these two clocks (pclk and hclk) are arranged, but I'm trying to get > some insight about that from various sources. While we're waiting for some > (hopefully) more certain info, I'd like to speculate a bit. I would say that > they both probably be either external (just like xosc), or generated internally > to the RP1: > > If externals, I would place them in the same position as xosc, so root node > or some other node under root (eg.: /rp1-clocks) Just like /clocks, /rp1-clocks is not better. Neither /rp1-foo-clocks. I think there is some sort of big misunderstanding here. Is this RP1 co-processor on the RP board, connected over PCI to Broadcom SoC? > > If internals, I would leave them just where they are, i.e. inside the rp1 node > > Does it make sense? No, because you do not have xosc there, according to my knowledge. Best regards, Krzysztof