From mboxrd@z Thu Jan 1 00:00:00 1970 From: t.figa@samsung.com (Tomasz Figa) Date: Mon, 20 Jan 2014 17:24:17 +0100 Subject: [PATCH RFC 04/10] base: power: Add generic OF-based power domain look-up In-Reply-To: <87r48a8t99.fsf@linaro.org> References: <1389469372-17199-1-git-send-email-tomasz.figa@gmail.com> <1389469372-17199-5-git-send-email-tomasz.figa@gmail.com> <87r48a8t99.fsf@linaro.org> Message-ID: <52DD4DB1.2050200@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Kevin, On 14.01.2014 16:42, Kevin Hilman wrote: > Tomasz Figa writes: > >> This patch introduces generic code to perform power domain look-up using >> device tree and automatically bind devices to their power domains. >> Generic device tree binding is introduced to specify power domains of >> devices in their device tree nodes. >> >> Backwards compatibility with legacy Samsung-specific power domain >> bindings is provided, but for now the new code is not compiled when >> CONFIG_ARCH_EXYNOS is selected to avoid collision with legacy code. This >> will change as soon as Exynos power domain code gets converted to use >> the generic framework in further patch. >> >> Signed-off-by: Tomasz Figa > > I haven't read through this in detail yet, but wanted to make sure that > the DT representation can handle nested power domains. At least > SH-mobile has a hierarchy of power domains and the genpd code can handle > that, so wanted to make sure that the DT representation can handle it as > well. The representation of power domains themselves as implied by this patch is fully platform-specific. The only generic part is the #power-domain-cells property, which defines the number of cells needed to identify the power domain of given provider. You are free to have any platform-specific properties (or even generic ones, added on top of this patch) to let you specify the hierarchy in DT. Best regards, Tomasz