From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 389AE2F43 for ; Tue, 8 Apr 2025 00:23:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744071803; cv=none; b=tIFKvn1B2W41RJuZFXrQ2JyW1N+ohGSYYpAACX4gGxRW2a2by25ZK0wrRRfpNWDnKXSbNf5vBpS8/L2DNCIGSagyr7b1sSGs8VBhbRg0csH4wsMS7D3xGeDOwRKpKTv+ippcL1qzwSctSprYRmArx0FWUK69ubQwcLveyPUE3QA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744071803; c=relaxed/simple; bh=ouIomqyx/7LCKmpY4hDD5EkkxS9+SnX8cGowOWWEpk0=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=h1/ELJUUsBfNdj791b0YD2aJyYj9vLwf/C4r79kEOZUJDaEfO5K1TQusdNUtzfV9Co7otpNR+mhOijjWonpJGwmnhXAZh6wyzLR4jaME+LjjA7cNWoWvADuWPFFfnv0QnzEFZPrHUf2uv+P3q3+EbujNB6+Qn5zLB3i06OSTCeU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=kernel.org; spf=pass smtp.mailfrom=baylibre.com; arc=none smtp.client-ip=209.85.214.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=kernel.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=baylibre.com Received: by mail-pl1-f169.google.com with SMTP id d9443c01a7336-22548a28d0cso68479545ad.3 for ; Mon, 07 Apr 2025 17:23:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1744071798; x=1744676598; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=XbhOTi4aXW0WOqTc6xfbySmStx3aI/FhVLl8UDRj7Sc=; b=NHt5XDMguJwN3DfoeLy2KIcTEmvnP4gwtwCS7DfYVLKYoKGbIICZBg3OGjaTG8Hyhc HlHHsK9rsqh4GFe9At257nxknO5K+rCdwF4x+U5hRVPoapygGtJneJebQnv1whtUR1kQ 4VZO7hwuE8lS2sBqdcSPpTkAQku09VGt1KyB4NPrElGu3iM+nxz87rEOuoxvbRhU1d/K GIAogYm6nzN/+K2VZHj/uKo7EzQNfAJz1kywPRfHnD9VI+rH/GYsbGnd7R9NdG2H5cMy mRK51DmjDe95IBCMQiaudfS70WsxzW50BAvPuV8GASNT/Ty92XICskcazBB+ijqcd/T6 SQAA== X-Forwarded-Encrypted: i=1; AJvYcCVobfCcrrDqVV9RhrXHW5C8d1KBHomBiq7SYuavSesHdD3ucwDxSXvCdxOB/oP4J/x6gG3tDYA8ag==@vger.kernel.org X-Gm-Message-State: AOJu0YwINiH9YPAAyZdnXuwH5Mc3Vtd//W/vYwEH5qxusHlRVDGBahP2 aouPQLMnoFtE+OWoRQz8jcOoAI8/HC10ljzpF07jZ3iLphivdrvaS/McSctRH9c= X-Gm-Gg: ASbGncsgw3EpzrGzhI5fkhKqTSWCwcmsvfKz5fr2SfGmAKt8nnHkhqnSt5+FAzrzD1b vpXiPgzICTs3bG1ajy0/TM1C85airkJrmaLXySZMJ2Z3Wnr6Sox1Z41JSARvtfJ+LF/kJfUl8Ig Ek4GQBIDxeBga8R9KsmoXkt2pvv69HwXAptRDiYgCx/6aLNGN+hyTtCDsoc/At2/nUCf1n3Dz6s 4iGOv6DPUZIsZ6dcXgBRz3urp+oUO69F0HF1fUAuRVvLhDrk8guqdupsiNzsIGhIOUHdkMZ78Dk G1oruwza1kYys7DNae5NHvJCoLIgBjAu6gy4CS5KbO0= X-Google-Smtp-Source: AGHT+IEfbVpQr7n3Rek4JwLzMB1Jhs0NtY0BLMo+44//Fm0/Ybd/+gL88i1Pnk/RYLQd2OQ5PIwp4Q== X-Received: by 2002:a17:903:3c44:b0:223:4b88:780f with SMTP id d9443c01a7336-22a8a85bd97mr202207985ad.17.1744071798463; Mon, 07 Apr 2025 17:23:18 -0700 (PDT) Received: from localhost ([97.126.182.119]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-229787776adsm87876715ad.247.2025.04.07.17.23.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Apr 2025 17:23:17 -0700 (PDT) From: Kevin Hilman To: Souvik Chakravarty , Peng Fan , Ulf Hansson , Vincent Guittot Cc: Sudeep Holla , Peng Fan , "cristian.marussi@arm.com" , Dan Carpenter , "arm-scmi@vger.kernel.org" , Chuck Cannon Subject: Re: POWER_DOMAIN_ATTRIBUTES in SCMI In-Reply-To: <81580b24-e11c-40c4-a709-5ad0feab8841@arm.com> References: <20250218130823.GA17099@nxa18884-linux> <20250218163146.GB15753@nxa18884-linux> <81580b24-e11c-40c4-a709-5ad0feab8841@arm.com> Date: Mon, 07 Apr 2025 17:23:17 -0700 Message-ID: <7h7c3vh56y.fsf@baylibre.com> Precedence: bulk X-Mailing-List: arm-scmi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Souvik Chakravarty writes: > Some quick thoughts below to keep this architecturally consistent. [...] > There are 2 ways to wakeup a device: > a) The device is powered by one or more PDs, one or more of which needs > to be kept ON to trigger the wakeup. > b) The device is powered by one or more PDs, but none of them are > required to trigger a wakeup. The device wake is derived from an out of > band logic which is kept powered ON (either transparently to OS, or via > another PD which does NOT belong to the device). In the case of TI SoCs, it's (b). In fact, most of the IO pads on the SoC can be enabled as wakeup capable when the SoC hits certain low-power states. The bits to control this are part of the pinctrl settings for the each driver on these SoCs. So technically it's neither the device nor its power domain that cause the wakeup, but the external pad, aided by some dedicated, always-on hardware, called "IO daisy chain" in the TI documentation[1]. Kevin [1] c.f Section 6.2.3.11 I/O Power Management and Daisy Chaining in the AM62L TRM for b bit more details: https://www.ti.com/lit/pdf/sprujb4