From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 21C32E6896B for ; Thu, 31 Oct 2024 09:49:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=pbHwqf27Q1FvtKnWgxyBf23bBy1UkWkgis24I8TTEI8=; b=gCBuaaA/DXIPnnfqzrGDsLGF0f sGjDhhLb2mhYsd5dOlG/p8ZQMtZQib5FiJTjUWmycJyGNriFjawJlYgnU0BGKznrdGzBw8HEHjgUf NASmcBgc+ez2S1uVUKzFZNxwCv/Kd/tbJLxOD5QErZrJNFoaMDGLNH9yEJFxxSc+sSyvAWxH3hKni BMeEiEgApfxJ5N3E54G/4KYLaTMHcUoXs9ExEGs28lXjXXo3a0LVh7DLwLETlzyzwvcU7hCytmgw1 +6+Q9DevMWqt+aqRUoE2YaEQ5vjJ5NbrwJDQrGL35azWwm2BoZCNrEhnw8KLplCrPa1CIcKy0yS2f BDSlumjA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t6RnM-000000038RA-070P; Thu, 31 Oct 2024 09:48:48 +0000 Received: from nyc.source.kernel.org ([147.75.193.91]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t6Rlf-000000038Cf-4AIk for linux-arm-kernel@lists.infradead.org; Thu, 31 Oct 2024 09:47:05 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 48E73A43E0A; Thu, 31 Oct 2024 09:45:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96918C4CEC3; Thu, 31 Oct 2024 09:46:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730368022; bh=14EtJIhlpM+v+RMq+CVjwcw2wUF+OrDzYqWObG4FJgA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=IZstoKDKKzDLkYiDEvMejvA8SBJXvf+X4vt8iaEs7uCcfiO+7jmy1JmLq968Mw7Xr AKxBtsb7S+SaG5vOHA3BcPPe28DT9DnSa+kXy1y1jTNJQAmL/dmZxNOFPPISUjJFm3 fZt4y8xofetZ6LcQUXHS3bQZfL/jykiB/pN71RLo4T/nrdFdNIdadx72C59t6uThNt M72lj8bkg4UEJocBRQO3ryHkd/gkUlgfwmCozbzkda99Rn9jMVvv+qe1PMrecrKsvj OWKhAWOH12Pn05VbEuHeX3aw3OA5IgdIhiFvySXduI/bi+P3+pCFIB8m2yKKmg91px cfm2P2Wyc4RsA== Message-ID: Date: Thu, 31 Oct 2024 10:46:53 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 03/10] clk: renesas: clk-vbattb: Add VBATTB clock driver To: Claudiu Beznea , Geert Uytterhoeven Cc: mturquette@baylibre.com, sboyd@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, alexandre.belloni@bootlin.com, magnus.damm@gmail.com, p.zabel@pengutronix.de, linux-renesas-soc@vger.kernel.org, linux-clk@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rtc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Claudiu Beznea References: <20241030110120.332802-1-claudiu.beznea.uj@bp.renesas.com> <20241030110120.332802-4-claudiu.beznea.uj@bp.renesas.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241031_024704_183740_F92581FC X-CRM114-Status: GOOD ( 16.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 31/10/2024 10:26, Claudiu Beznea wrote: > Hi, Geert, Krzysztof, > > On 31.10.2024 10:43, Geert Uytterhoeven wrote: >> Hi Krzysztof, >> >> On Thu, Oct 31, 2024 at 8:48 AM Krzysztof Kozlowski wrote: >>> On Wed, Oct 30, 2024 at 01:01:13PM +0200, Claudiu wrote: >>>> From: Claudiu Beznea >>>> >>>> The VBATTB IP of the Renesas RZ/G3S SoC controls the clock that is used >>>> by the RTC. The input to the VBATTB could be a 32KHz crystal >>>> or an external clock device. >>>> >>>> The HW block diagram for the clock generator is as follows: >>>> >>>> +----------+ XC `\ >>>> RTXIN --->| |----->| \ +----+ VBATTCLK >>>> | 32K clock| | |----->|gate|-----------> >>>> | osc | XBYP | | +----+ >>>> RTXOUT --->| |----->| / >>>> +----------+ , >>>> >>>> After discussions w/ Stephen Boyd the clock tree associated with this >>>> hardware block was exported in Linux as: >>>> >>>> vbattb-xtal >>>> xbyp >>>> xc >>>> mux >>>> vbattbclk >>>> >>>> where: >>>> - input-xtal is the input clock (connected to RTXIN, RTXOUT pins) >>>> - xc, xbyp are mux inputs >>>> - mux is the internal mux >>>> - vbattclk is the gate clock that feeds in the end the RTC >>>> >>>> to allow selecting the input of the MUX though assigned-clock DT >>>> properties, using the already existing clock drivers and avoid adding >>>> other DT properties. If the crystal is connected on RTXIN, >>>> RTXOUT pins the XC will be selected as mux input. If an external clock >>>> device is connected on RTXIN, RTXOUT pins the XBYP will be selected as >>>> mux input. >>>> >>>> The load capacitance of the internal crystal can be configured >>>> with renesas,vbattb-load-nanofarads DT property. >>>> >>>> Reviewed-by: Geert Uytterhoeven >>>> Signed-off-by: Claudiu Beznea >> >>>> --- a/drivers/clk/renesas/Kconfig >>>> +++ b/drivers/clk/renesas/Kconfig >>>> @@ -237,6 +237,10 @@ config CLK_RZV2H >>>> bool "RZ/V2H(P) family clock support" if COMPILE_TEST >>>> select RESET_CONTROLLER >>>> >>>> +config CLK_RENESAS_VBATTB >>>> + bool "Renesas VBATTB clock controller" >>> >>> tristate >> >> Good point. >> However, does it work as a module, or would that break the RTC? > > On RZ/G3S the RTC counter needs the clock provided by VBATTB. > > I'll try with this as a module. So it will defer, why would this be a problem? This does not look like critical core component, which would halt the system probe (and even then systems like Android put everything as modules). Best regards, Krzysztof