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 10AC910E0; Tue, 22 Oct 2024 05:11:45 +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=1729573906; cv=none; b=pDVoTyENzLvb63y57EqhogwXQb9Jbm8POyIUexK08GL4m18lVy3H4KjYCs2OPcuWRxZhSwr2rVLYnJwCsWHb9NFE+2Zbe4DJQHXFRzibzEXWK6jmCVcuXFkeO/yvMSNoPGizz9Ej10WbtTdy9yJlAOyDS+IkKI+IpCduCFgDWT8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729573906; c=relaxed/simple; bh=77///Hghh184qaPOXx3OjQPZRdLqRN10rmRRS+IaLto=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=dYBKSBZ0yy1h6merb2kTKRS2p6GGEak72qcDF8pJhnBaJQm5hMJQyACGwpyE6yjQL8BVSTAW0A41vKvtJYAeuUM0hne4L9xeQZV4bGb7P0cSDTGzQLOcWWZDzOBC5efS4AFrBwowtYeR1TQ/Foi2bw2v7oPwOdxEVy+NKB9qPdw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mu60vOcQ; 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="mu60vOcQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6A97C4CEC3; Tue, 22 Oct 2024 05:11:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729573905; bh=77///Hghh184qaPOXx3OjQPZRdLqRN10rmRRS+IaLto=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=mu60vOcQtKJUhNQVlvcjbHMjXfGgK2l/h8rykjvHFRKIlBcxkiXx00rrpY21GykkH 1bWy0BOFIvxR8/pfJxkg7oRmgXDoIfZ0IzAz5nWHnJOyFxDTqRdVtVf087iJh8N5CC 0uq9CrtyfBirHb7mv9g8hgpWpYnZIWfkYscx/v8KA9tGDSeacPCWP3wjVRPudjaHMM QJz1V6RygnHcvpVvtBgVqXv+aQVF7A+QiSaWaIkdZmYgXTF/K1ZzKkcq8CdDpDRURQ ozBi9urCkLxzCAwA2TaGPp7LnOpQ4ydwIpc34+jj3ajuKA3SLqPseMooTtIb/z5zJR INcN5y1baoVFQ== Message-ID: Date: Tue, 22 Oct 2024 07:11:36 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] dt-bindings: net: bluetooth: nxp: add support for supply and reset To: Marco Felsch Cc: POPESCU Catalin , Sherry Sun , Amitkumar Karwar , Neeraj Sanjay Kale , "marcel@holtmann.org" , "luiz.dentz@gmail.com" , "robh@kernel.org" , "krzk+dt@kernel.org" , "conor+dt@kernel.org" , "p.zabel@pengutronix.de" , "linux-bluetooth@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , GEO-CHHER-bsp-development References: <20241004113557.2851060-1-catalin.popescu@leica-geosystems.com> <3fa35cd2-e52c-4873-8a7f-db459b016a97@kernel.org> <2b7f61a8-e91a-4b32-be1d-753a19e4d81f@leica-geosystems.com> <0d460226-4ea7-4a9b-a119-468343727996@kernel.org> <20241021064129.trchqa2oickna7pc@pengutronix.de> <20241021102558.rfnz7nxcg5knibxs@pengutronix.de> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 21/10/2024 12:25, Marco Felsch wrote: > On 24-10-21, Krzysztof Kozlowski wrote: >> On 21/10/2024 08:41, Marco Felsch wrote: >>> On 24-10-07, Krzysztof Kozlowski wrote: >>>> On 07/10/2024 14:58, POPESCU Catalin wrote: >>>>>>>> >>>>>>>> + vcc-supply: >>>>>>>> + description: >>>>>>>> + phandle of the regulator that provides the supply voltage. >>>>>>>> + >>>>>>>> + reset-gpios: >>>>>>>> + description: >>>>>>>> + Chip powerdown/reset signal (PDn). >>>>>>>> + >>>>>>> Hi Catalin, >>>>>>> >>>>>>> For NXP WIFI/BT chip, WIFI and BT share the one PDn pin, which means that both wifi and BT controller will be powered on and off at the same time. >>>>>>> Taking the M.2 NXP WIFI/BT module as an example, pin56(W_DISABLE1) is connected to the WIFI/BT chip PDn pin, we has already controlled this pin in the corresponding PCIe/SDIO controller dts nodes. >>>>>>> It is not clear to me what exactly pins for vcc-supply and reset-gpios you describing here. Can you help understand the corresponding pins on M.2 interface as an example? Thanks. >>>>> >>>>> Hi Sherry, >>>>> >>>>> Regulators and reset controls being refcounted, we can then implement >>>>> powerup sequence in both bluetooth/wlan drivers and have the drivers >>>>> operate independently. This way bluetooth driver would has no dependance >>>>> on the wlan driver for : >>>>> >>>>> - its power supply >>>>> >>>>> - its reset pin (PDn) >>>>> >>>>> - its firmware (being downloaded as part of the combo firmware) >>>>> >>>>> For the wlan driver we use mmc power sequence to drive the chip reset >>>>> pin and there's another patchset that adds support for reset control >>>>> into the mmc pwrseq simple driver. >>>>> >>>>>> Please wrap your replies. >>>>>> >>>>>> It seems you need power sequencing just like Bartosz did for Qualcomm WCN. >>>>> >>>>> Hi Krzysztof, >>>>> >>>>> I'm not familiar with power sequencing, but looks like way more >>>>> complicated than reset controls. So, why power sequencing is recommended >>>>> here ? Is it b/c a supply is involved ? >>>> >>>> Based on earlier message: >>>> >>>> "For NXP WIFI/BT chip, WIFI and BT share the one PDn pin, which means >>>> that both wifi and BT controller will be powered on and off at the same >>>> time." >>>> >>>> but maybe that's not needed. No clue, I don't know the hardware. But be >>>> carefully what you write in the bindings, because then it will be ABI. >>> >>> We noticed the new power-sequencing infrastructure which is part of 6.11 >>> too but I don't think that this patch is wrong. The DT ABI won't break >>> if we switch to the power-sequencing later on since the "reset-gpios" >>> are not marked as required. So it is up to the driver to handle it >>> either via a separate power-sequence driver or via "power-supply" and >>> "reset-gpios" directly. >> >> That's not the point. We expect correct hardware description. If you say >> now it has "reset-gpios" but later say "actually no, because it has >> PMU", I respond: no. Describe the hardware, not current Linux. > > I know that DT abstracts the HW. That said I don't see the problem with > this patch. The HW is abstracted just fine: > > shared PDn -> reset-gpios > shared power-supply -> vcc-supply > > Right now the DT ABI for the BT part is incomplete since it assume a > running WLAN part or some hog-gpios to pull the device out-of-reset > which is addressed by this patchset. > > Making use of the new power-sequencing fw is a Linux detail and I don't > see why the DT can't be extended later on. We always extend the DT if > something is missing or if we found a better way to handle devices. Sure, although I am not really confident that you understand the implications - you will not be able to switch to proper power-sequencing with above bindings, because it will not be just possible without breaking the ABI or changing hardware description (which you say it is "fine", so complete/done). I am fine with it, just mind the implications. Best regards, Krzysztof