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smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=FfC9PGeZ; arc=none smtp.client-ip=217.70.183.200 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="FfC9PGeZ" Received: by mail.gandi.net (Postfix) with ESMTPSA id 8076F44191; Thu, 13 Feb 2025 12:54:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1739451284; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=YBQYwQdRIQ20yozFfxJGyrrPezD83gPdJ94AG2odwmc=; b=FfC9PGeZopcSlMED939jJp01G7c43ji4lIsjeMGMdWf9BzbCs1A2yB+5sz31xizjVHXutY Qa7paCmQ3QlxzcBuYBE4JR9K5Tr7X3wI4bNjZUMkzkZ8xDcahMb9pyduRn+mKtI65+ymL+ OYM3VkmT3wf2h0DQVsHYBCqJ3yP54S+LG5x3z2SdZkLJmGQJp1dSfPruDnEMdcWutO7GgZ KUL9T+OD6FgcieBuI9taJNS72yKDVGCkI8J68dBphVqPAdqHnh0CMIqAsRtarlFa5WO8gQ RMT6L7BMK0fvIZHxAbmh+D6RBt4sE5Z2CegRx6RzC1xmOvw0As4m3Ld4EZBsTg== Date: Thu, 13 Feb 2025 13:54:42 +0100 From: Alexandre Belloni To: Peng Fan Cc: Sudeep Holla , Peng Fan , "cristian.marussi@arm.com" , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , "arm-scmi@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "imx@lists.linux.dev" , "linux-kernel@vger.kernel.org" , "linux-rtc@vger.kernel.org" Subject: Re: [PATCH 0/4] rtc/scmi: Support multiple RTCs Message-ID: <2025021312544202e175b4@mail.local> References: <20250212063532.GB15796@localhost.localdomain> <20250212170147ee6863dc@mail.local> <20250213033033.GA21937@localhost.localdomain> <20250213082032315c4327@mail.local> <20250213105257.GA29804@localhost.localdomain> <202502131126057bac6f7a@mail.local> <20250213133550.GA1208@localhost.localdomain> Precedence: bulk X-Mailing-List: linux-kernel@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: <20250213133550.GA1208@localhost.localdomain> X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgdegieekvdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfitefpfffkpdcuggftfghnshhusghstghrihgsvgenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepfffhvfevuffkfhggtggujgesthdtredttddtvdenucfhrhhomheptehlvgigrghnughrvgcuuegvlhhlohhnihcuoegrlhgvgigrnhgurhgvrdgsvghllhhonhhisegsohhothhlihhnrdgtohhmqeenucggtffrrghtthgvrhhnpeegieduueethefhkeegjeevfefhiedujeeuhffgleejgfejgeekueejuefgheeggfenucffohhmrghinhepsghoohhtlhhinhdrtghomhenucfkphepvdgrtddumegtsgdugeemheehieemjegrtddtmegukeejvgemudgsudgsmeeltdekgeemtggtfhgtnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepvdgrtddumegtsgdugeemheehieemjegrtddtmegukeejvgemudgsudgsmeeltdekgeemtggtfhgtpdhhvghloheplhhotggrlhhhohhsthdpmhgrihhlfhhrohhmpegrlhgvgigrnhgurhgvrdgsvghllhhonhhisegsohhothhlihhnrdgtohhmpdhnsggprhgtphhtthhopedufedprhgtphhtthhopehpvghnghdrfhgrnhesohhsshdrnhigphdrtghomhdprhgtphhtthhopehsuhguvggvphdrhhholhhlrgesrghrmhdrtghomhdprhgtphhtthhopehpvghnghdrf hgrnhesnhigphdrtghomhdprhgtphhtthhopegtrhhishhtihgrnhdrmhgrrhhushhsihesrghrmhdrtghomhdprhgtphhtthhopehshhgrfihnghhuoheskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepshdrhhgruhgvrhesphgvnhhguhhtrhhonhhigidruggvpdhrtghpthhtohepkhgvrhhnvghlsehpvghnghhuthhrohhnihigrdguvgdprhgtphhtthhopehfvghsthgvvhgrmhesghhmrghilhdrtghomh X-GND-Sasl: alexandre.belloni@bootlin.com On 13/02/2025 21:35:50+0800, Peng Fan wrote: > >Well, yes, you have your answer here, if the firmware knows RTC1 is more > >accurate and will be your source of truth, then simply use this one. > > But issue is RTC1 is only readable to Linux non-safety, Linux not able > to set alarm. Linux could only use RTC0 for alarm with current i.MX95 EVK > firmware. > > If RTC1 could be exported to linux for control, we could for sure > switch to using RTC1 without caring about RTC0. But this is not true. > > RTC0 is free for linux to control, RTC1 not. Switching to RTC1 will make > us lose RTC alarm to wake up linux feature. > This doesn't make any sense, this limitation is on your firmware side, either RTC1 has alarm support and the firmware can set the alarm for linux or it doesn't and then, the firmware must set the time and alarm on RTC0. -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com