From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Sender: rtc-linux@googlegroups.com Received: from mail-out1.kundencontroller.de (mail-out1.kundencontroller.de. [2a02:180:ffff:1::551f:b822]) by gmr-mx.google.com with ESMTPS id x70si36258wmf.1.2016.07.06.22.11.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 Jul 2016 22:11:41 -0700 (PDT) Subject: [rtc-linux] Re: [PATCH] rtc: sunxi: use external oscillator To: Maxime Ripard References: <577CC494.8020103@roslen.de> <20160706202000.GC4247@lukather> <577DDF8C.6060404@roslen.de> Cc: a.zummo@towertech.it, alexandre.belloni@free-electrons.com, wens@csie.org, rtc-linux@googlegroups.com From: Stephan Roslen Message-ID: <577DE48B.2020009@roslen.de> Date: Thu, 7 Jul 2016 07:11:39 +0200 MIME-Version: 1.0 In-Reply-To: <577DDF8C.6060404@roslen.de> Content-Type: text/plain; charset=UTF-8 Reply-To: rtc-linux@googlegroups.com List-ID: List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , On 07.07.2016 06:50, Stephan Roslen wrote: > On 06.07.2016 22:20, Maxime Ripard wrote: >> The issue is actually worse than that. >> >> That register controls the losc source for the whole clock tree, so it >> will affect every clock in the system. >> >> In order to have that correctly propagated, you should register a new >> mux here in the clock framework, and have all the other clocks using >> that mux as a parent. >=20 > I agree. Checking the diagram in subsection 1.5.2 of the A20 manual it se= ems, that LOSC can be a source for clocks like CPU and some SoC busses. So = my patch could indeed mess with the whole clock tree. Sorry for the addition. The mess of course is not that huge, for the mux se= lects between a 32KHz Oscillator with +- 20% tolerance, thus ranging from 2= 5.6 to 38.4 KHz and the 32.768KHz external oscillator. Hence muxing to 32.7= 68KHz should be no problem for any clk, that was fine with the internal osc= illator as clk source. Though still you're absolutely right, that this shou= ld be handled in code correctly. Stephan --=20 You received this message because you are subscribed to "rtc-linux". Membership options at http://groups.google.com/group/rtc-linux . Please read http://groups.google.com/group/rtc-linux/web/checklist before submitting a driver. ---=20 You received this message because you are subscribed to the Google Groups "= rtc-linux" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to rtc-linux+unsubscribe@googlegroups.com. For more options, visit https://groups.google.com/d/optout.