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 E2F4913AD0; Tue, 22 Oct 2024 07:31:05 +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=1729582266; cv=none; b=TCcqMp/p80hNSekm4VgFhOyCh820SrY4y/gr53rQ09GmIhccf5mwsyQVC9XSNcPdcU4Vk2gsz1y1Y4QeIToW+9UW6uLvoQQPwx1+HDShh8pJ91hjrNkW/nM7EtJ8QEhwvtz1kdBMdx+H4rGvknX639qfQwRAPJj0P53Jb6RBoDs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729582266; c=relaxed/simple; bh=HCIa2AkrfDM2CEGtzVKU7MNYVqPZuefnJ8Ahx7FIIUM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=TDO9+zbvb8y5MX4GCHNBOsA+I8Pc3iiseOMnRx5gk0oUmK1GRkKut+4t977kfx4Wy4keWnTjmpS7G0kFW9zsJONT7TYP7o4u2XyE543xGXuxUt5ub1b/tIw+bbvbFg3Kmd4oGYcVvTIRlmnRf28vfVH/t7PYxOCUj7QoYeoKMBU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rUyQdqqT; 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="rUyQdqqT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 242D7C4CEE3; Tue, 22 Oct 2024 07:30:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729582265; bh=HCIa2AkrfDM2CEGtzVKU7MNYVqPZuefnJ8Ahx7FIIUM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=rUyQdqqTkBWDOn0RGwPmIsXUqU71/6fpNBw6IAOpIVsBuNW1S0dasyOjjLF5AOTit mE59TEkO8GvQSSbrIp6HnVNld4u7xhOTlwsCtKu5u7JNbbgKj+ALpheqrHDdCDG2Hk MpzN2Qh9/B3Xq0Brf1pytyXazH71JLBGnmOWIidpZ8WavR2Ks5oYkvtFuBOq+MSTWW 7bvZGCV0CxFBoDaEMTN/LYTvWjTB9oP8K+IjVe3yKlumMiyApbwW+q8C1bRhvvJWAd powHexKja+nLAhEFjrp9K40oytorWEMfpkoEfmHn8nu6xn4Y26+V6Rf3I2gkFDaxzo n5wKIdNpKHX2A== Message-ID: <66d33097-37ed-4e89-a356-285eda743a5c@kernel.org> Date: Tue, 22 Oct 2024 09:30:56 +0200 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 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> <20241022071208.lgk2rpl2c2qpytfa@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 22/10/2024 09:12, Marco Felsch wrote: > On 24-10-22, Krzysztof Kozlowski wrote: >> 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: > > ... > >>>>>> 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. > > Sorry can you please share your concerns? I don't get the point yet why > we do break the DT ABI if we are going from Not necessarily breaking ABI, but changing the description. > > bt { > reset-gpios = <&gpio 4 0>; > vcc-supply = <&supply>; > }; > > to > > bt { > vcc-supply = <&pmu_supply>; ...because you just removed reset-gpios which is a property of this device. > }; > > or: > > bt { > pmu = <&pmu>; > }; > > Of course the driver need to support all 2/3 cases due to backward > compatibility but from DT pov I don't see any breakage since we already > need to define the power handling properties (gpio & supply) as > optional. Either existing binding is complete or not. Not half-done. > > That beeing said I don't see the need for a PMU driver for this WLAN/BT > combi chip which is way simpler than the Qualcomm one from Bartosz. Also > there is physically no PMU device which powers the chip unlike the > Qualcomm one. I'm not sure if you would accept virtual PMU devices. Virtual PMU, of course not. I would like to have complete hardware description, not something which matches your current driver model. Best regards, Krzysztof