From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Figa Subject: Re: [PATCH v4 06/11] ARM: EXYNOS: Add support for mapping PMU base address via DT Date: Tue, 10 Jun 2014 19:10:35 +0200 Message-ID: <53973C0B.2000903@samsung.com> References: <1399704998-13321-1-git-send-email-pankaj.dubey@samsung.com> <1399704998-13321-7-git-send-email-pankaj.dubey@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mailout2.w1.samsung.com ([210.118.77.12]:48781 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751851AbaFJRKx (ORCPT ); Tue, 10 Jun 2014 13:10:53 -0400 In-reply-to: <1399704998-13321-7-git-send-email-pankaj.dubey@samsung.com> Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Pankaj Dubey , linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: kgene.kim@samsung.com, linux@arm.linux.org.uk, chow.kim@samsung.com, yg1004.jang@samsung.com, vikas.sajjan@samsung.com Hi, On 10.05.2014 08:56, Pankaj Dubey wrote: > From: Young-Gun Jang > > Add support for mapping Samsung Power Management Unit (PMU) > base address from device tree. This patch also adds helper > function as "get_exynos_pmuregmap". This function can be used > by other machine files such as "pm.c", "hotplug.c" for accessing > PMU regmap handle. > I don't think there is a need to use regmap to provide access to PMU to such low level code such as pm.c or hotplug.c. Moreover, I believe that it might be undesirable in some cases, e.g. very low level code running at early resume or late suspend. IMHO, based on what we now have for SYSRAM, you could simply map PMU from device tree one time, before SMP init, and keep the address in some globally accessible variable, like those for SYSRAM we have right now (sysram_base_addr, sysram_ns_base_addr -> pmu_base_addr). Then, registration of the normal syscon would happen through standard platform driver mechanisms and no special early handling would be necessary. Best regards, Tomasz From mboxrd@z Thu Jan 1 00:00:00 1970 From: t.figa@samsung.com (Tomasz Figa) Date: Tue, 10 Jun 2014 19:10:35 +0200 Subject: [PATCH v4 06/11] ARM: EXYNOS: Add support for mapping PMU base address via DT In-Reply-To: <1399704998-13321-7-git-send-email-pankaj.dubey@samsung.com> References: <1399704998-13321-1-git-send-email-pankaj.dubey@samsung.com> <1399704998-13321-7-git-send-email-pankaj.dubey@samsung.com> Message-ID: <53973C0B.2000903@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On 10.05.2014 08:56, Pankaj Dubey wrote: > From: Young-Gun Jang > > Add support for mapping Samsung Power Management Unit (PMU) > base address from device tree. This patch also adds helper > function as "get_exynos_pmuregmap". This function can be used > by other machine files such as "pm.c", "hotplug.c" for accessing > PMU regmap handle. > I don't think there is a need to use regmap to provide access to PMU to such low level code such as pm.c or hotplug.c. Moreover, I believe that it might be undesirable in some cases, e.g. very low level code running at early resume or late suspend. IMHO, based on what we now have for SYSRAM, you could simply map PMU from device tree one time, before SMP init, and keep the address in some globally accessible variable, like those for SYSRAM we have right now (sysram_base_addr, sysram_ns_base_addr -> pmu_base_addr). Then, registration of the normal syscon would happen through standard platform driver mechanisms and no special early handling would be necessary. Best regards, Tomasz