From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from mail-ot1-f48.google.com (mail-ot1-f48.google.com [209.85.210.48]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B6EF1A8; Thu, 16 Nov 2023 11:23:32 -0800 (PST) Received: by mail-ot1-f48.google.com with SMTP id 46e09a7af769-6d645cfd238so665307a34.2; Thu, 16 Nov 2023 11:23:32 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700162611; x=1700767411; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=11ZdWcm9xn9/03dHAna0VIYX27sSKjstDA9LwDlSCCE=; b=WAdCkhEzQk+We1ZpMM7aFrlB9lO2C5OlJ3wU21Ptnnw2BL8t4nRfmnVPWViNyxbDDx v7KA/wo+ZUE9PlWLX5IldpsJF0nAkTSON9knm0l6fp35JoGHUJW8RIjxPesq6MFkvU7e p1gyE/Zyd2aiKY/V65OYBuni8g1/kTdfCW7k2C3LVq843HM7b4ndzjWW/rLmAT7v3/Tm 0q5zp+FDKGMtsuibltN6W7h/pUjp5iV00Q85avv+Uh/o/GSUSV6xFau+kqnLFenvcNBc pbwEoJYCqtTb4zVFHtCGD/iGg21XoNLgHKZI9cQf1yUdA9JUDk8PZnAVa2p89HlK4695 XTng== X-Gm-Message-State: AOJu0Yx4VxPm7wz16hlxMbtWui5wIW5MGkDUZ72oIFf1dYR6DJb+wKVQ fPiMGKG8d5Z2+1lsdYVeOg== X-Google-Smtp-Source: AGHT+IFFflHQDgRWcv8Aa0Xfi5zkFhUmKL2WYSX7jkOBDfAipGIi5WM/EhkIhHPanJyZbmYMTEsu6g== X-Received: by 2002:a9d:6f8c:0:b0:6d6:45b1:faff with SMTP id h12-20020a9d6f8c000000b006d645b1faffmr9490888otq.30.1700162611533; Thu, 16 Nov 2023 11:23:31 -0800 (PST) Received: from herring.priv (66-90-144-107.dyn.grandenetworks.net. [66.90.144.107]) by smtp.gmail.com with ESMTPSA id bg22-20020a056830361600b006d309c126fbsm1006744otb.57.2023.11.16.11.23.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Nov 2023 11:23:30 -0800 (PST) Received: (nullmailer pid 3022585 invoked by uid 1000); Thu, 16 Nov 2023 19:23:24 -0000 Date: Thu, 16 Nov 2023 13:23:24 -0600 From: Rob Herring To: Kuninori Morimoto Cc: Frank Rowand , Geert Uytterhoeven , Michael Turquette , Stephen Boyd , devicetree@vger.kernel.org, linux-clk@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Aymeric Aillet , Yusuke Goda Subject: Re: [PATCH 4/4] drivers: clk: renesas: enable all clocks which is assinged to non Linux system Message-ID: <20231116192324.GB2821275-robh@kernel.org> References: <8734x9tda9.wl-kuninori.morimoto.gx@renesas.com> <87wmulrynq.wl-kuninori.morimoto.gx@renesas.com> Precedence: bulk X-Mailing-List: linux-clk@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87wmulrynq.wl-kuninori.morimoto.gx@renesas.com> On Tue, Nov 14, 2023 at 12:01:14AM +0000, Kuninori Morimoto wrote: > Some board might use Linux and another OS in the same time. In such > case, current Linux will stop necessary module clock when booting > which is not used on Linux side, but is used on another OS side. > > To avoid such situation, renesas-cpg-mssr try to find > status = "reserved" devices (A), and add CLK_IGNORE_UNUSED flag to its > <&cgp CPG_MOD xxx> clock (B). See Stephen's presentation from Plumbers this week. The default behavior for unused clocks may be changing soon. > > Table 2.4: Values for status property > https://github.com/devicetree-org/devicetree-specification/releases/download/v0.4/devicetree-specification-v0.4.pdf > > "reserved" > Indicates that the device is operational, but should not be > used. Typically this is used for devices that are controlled > by another software component, such as platform firmware. > > ex) > scif5: serial@e6f30000 { > ... > (B) clocks = <&cpg CPG_MOD 202>, > <&cpg CPG_CORE R8A7795_CLK_S3D1>, > <&scif_clk>; > ... > (A) status = "reserved"; > }; I have some reservations about whether a reserved node should be touched at all by Linux. I suppose since it is platform specific, it's okay. I don't think we could apply such behavior globally. Rob