From mboxrd@z Thu Jan 1 00:00:00 1970 From: Saravana Kannan Subject: Re: [RFC 2/2] clk: samsung: add exynos5250 composite clock for hdmi Date: Mon, 20 May 2013 13:02:57 -0700 Message-ID: <519A8171.3040003@codeaurora.org> References: <1369059428-26820-1-git-send-email-rahul.sharma@samsung.com> <1369059428-26820-3-git-send-email-rahul.sharma@samsung.com> <5956307.B4Gm3xbmhh@flatron> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5956307.B4Gm3xbmhh@flatron> Sender: linux-samsung-soc-owner@vger.kernel.org To: Tomasz Figa Cc: Rahul Sharma , kgene.kim@samsung.com, devicetree-discuss@lists.ozlabs.org, joshi@samsung.com, inki.dae@samsung.com, linux-samsung-soc@vger.kernel.org, s.nawrocki@samsung.com, r.sh.open@gmail.com List-Id: devicetree@vger.kernel.org On 05/20/2013 11:57 AM, Tomasz Figa wrote: > Hi Rahul, > > On Monday 20 of May 2013 19:47:08 Rahul Sharma wrote: >> HDMI driver needs to change the parent of sclk_hdmi clock to >> sclk_pixel or to sclk_hdmiphy, depends on the status of hdmiphy. >> sclk_hdmi which is gate clock doesn't support the set_parent >> operation. > > Wouldn't it be better to simply allow calling clk_set_parent() on gate > clocks and propagate parent change to nearest mux, just like it is done > with clk_set_rate()? > > It wouldn't require any SoC-specific composite clocks and keep the nice > property of the clock tree, which is built from basic, generic clock > blocks that nicely correspond to blocks shown in the documentation. > > We had discussed this already at SRPOL and got to the conclusion that it's > a step backwards, making the clock driver more complex, because each > composite block would have to be described using a structure with many > fields. In addition there are many special cases, for which the composite > scheme wouldn't work anyway and they would end up with simple clocks > attached after the composite block, defeating the purpose of your patch. > +1 to all these comments. -Saravana -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation