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dkim-atps=neutral AI-Spam-Status: Not processed Received: from [192.168.0.46] (unknown [14.154.30.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mail20.mymailcheap.com (Postfix) with ESMTPSA id 8D48D41BC6; Thu, 29 Jul 2021 08:05:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=aosc.io; s=default; t=1627545982; bh=MxHmdT4bsC43647pu5QM2aJET0ZwS2Bb3sTp+rRAXqs=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=wL7QlJcoPqMLq/nXtvFWnwybsQmHWtPSTk2Kmy+ZPkht1BUy52Q8B8PhstnLmbZrG kBy4VxKXZnjRXzhI19yi4OzYv8E4a6URGOOQ/J7ZeZ385gv8swRpXmlokN1of0yxRq 8IG0vcuhYv2vYraQHY9WhLXD4c44dwzd7TTn8aZ0= Message-ID: <1e49692a2f4548ae942e170bc1ae9431a6eb512e.camel@aosc.io> Subject: Re: [PATCH v7 06/19] rtc: sun6i: Add support for RTCs without external LOSCs From: Icenowy Zheng To: Maxime Ripard , Andre Przywara Cc: Chen-Yu Tsai , Jernej Skrabec , Rob Herring , Samuel Holland , linux-arm-kernel@lists.infradead.org, linux-sunxi@googlegroups.com, linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org, Ondrej Jirman , Alessandro Zummo , Alexandre Belloni , linux-rtc@vger.kernel.org Date: Thu, 29 Jul 2021 16:04:10 +0800 In-Reply-To: <20210616091431.6tm3zdf77p2x3upc@gilmour> References: <20210615110636.23403-1-andre.przywara@arm.com> <20210615110636.23403-7-andre.przywara@arm.com> <20210616091431.6tm3zdf77p2x3upc@gilmour> Content-Type: text/plain; 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SUSPICIOUS_RECIPS(1.50)[]; RCVD_COUNT_TWO(0.00)[2] Precedence: bulk List-ID: X-Mailing-List: linux-rtc@vger.kernel.org 在 2021-06-16星期三的 11:14 +0200，Maxime Ripard写道： > Hi, > > On Tue, Jun 15, 2021 at 12:06:23PM +0100, Andre Przywara wrote: > > Some newer Allwinner RTCs (for instance the one in the H616 SoC) > > lack > > a pin for an external 32768 Hz oscillator. As a consequence, this > > LOSC > > can't be selected as the RTC clock source, and we must rely on the > > internal RC oscillator. > > To allow additions of clocks to the RTC node, add a feature bit to > > ignore > > any provided clocks for now (the current code would think this is > > the > > external LOSC). Later DTs and code can then for instance add the > > PLL > > based clock input, and older kernel won't get confused. > > > > Signed-off-by: Andre Przywara > > Honestly, I don't really know if it's worth it at this point. > > If we sums this up: > >  - The RTC has 2 features that we use, mostly centered around 2 >    registers set plus a global one > >  - Those 2 features are programmed in a completely different way > >  - Even the common part is different, given the discussion around the >    clocks that we have. > > What is there to share in that driver aside from the probe, and maybe > the interrupt handling? Instead of complicating this further with > more > special case that you were (rightfully) complaining about, shouldn't > we > just acknowledge the fact that it's a completely separate design and > should be treated as such, with a completely separate driver? I think our problem is just that we're having a single driver for both functionalities (clock manager and RTC). Personally I don't think we should have seperated driver for clock managers, although I am fine with seperated RTC driver for linear days. By the way, not having a LOSC is only what happens on H616, maybe because there should never be a battery-backed H616 device. On R329, the RTC part has linear day storage, but it still have LOSC. Because of this, I don't think we should duplicate at least at least the current sun6i-rtc dual-functionality driver, because the clock funtionality is just the same with previous SoCs on R329. > > Maxime