From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [PATCH v9 07/22] clk: Add API to get index of the clock parent Date: Thu, 7 Nov 2019 03:54:03 +0300 Message-ID: References: <1565984527-5272-1-git-send-email-skomatineni@nvidia.com> <1565984527-5272-8-git-send-email-skomatineni@nvidia.com> <20191106231005.F2CD820869@mail.kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20191106231005.F2CD820869@mail.kernel.org> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Stephen Boyd , Sowjanya Komatineni , jason@lakedaemon.net, jonathanh@nvidia.com, linus.walleij@linaro.org, marc.zyngier@arm.com, mark.rutland@arm.com, stefan@agner.ch, tglx@linutronix.de, thierry.reding@gmail.com Cc: pdeschrijver@nvidia.com, pgaikwad@nvidia.com, linux-clk@vger.kernel.org, linux-gpio@vger.kernel.org, jckuo@nvidia.com, josephl@nvidia.com, talho@nvidia.com, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, mperttunen@nvidia.com, spatra@nvidia.com, robh+dt@kernel.org, devicetree@vger.kernel.org, rjw@rjwysocki.net, viresh.kumar@linaro.org, linux-pm@vger.kernel.org List-Id: linux-tegra@vger.kernel.org 07.11.2019 02:10, Stephen Boyd пишет: > Quoting Sowjanya Komatineni (2019-08-16 12:41:52) >> This patch adds an API clk_hw_get_parent_index to get index of the >> clock parent to use during the clock restore operations on system >> resume. > > Is there a reason we can't save the clk hw index at suspend time by > reading the hardware to understand the current parent? The parent index > typically doesn't matter unless we're trying to communicate something > from the framework to the provider driver. Put another way, I would > think the provider driver can figure out the index itself without having > to go through the framework to do so. Isn't it a bit wasteful to duplicate information about the parent within a provider if framework already has that info? The whole point of this new API is to allow providers to avoid that unnecessary duplication. Please note that clk_hw_get_parent_index is getting used only at the resume time and not at suspend. [snip]