From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Cousson, Benoit" Subject: Re: [PATCH 5/6] ARM: OMAP4: CLKDM: Update supported transition modes Date: Tue, 15 May 2012 16:40:30 +0200 Message-ID: <4FB26ADE.1060206@ti.com> References: <1336599364-11024-1-git-send-email-jon-hunter@ti.com> <4FAB6623.9090005@ti.com> <4FB2693E.7090303@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from bear.ext.ti.com ([192.94.94.41]:46855 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758237Ab2EOOki (ORCPT ); Tue, 15 May 2012 10:40:38 -0400 In-Reply-To: <4FB2693E.7090303@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Jon Hunter Cc: Santosh Shilimkar , linux-omap , Ming Lei , Will Deacon , Paul Walmsley , Kevin Hilman Hi Jon, On 5/15/2012 4:33 PM, Jon Hunter wrote: > Hi Santosh, Benoit, > > On 05/10/2012 01:54 AM, Santosh Shilimkar wrote: >> On Thursday 10 May 2012 03:06 AM, Jon Hunter wrote: >>> From: Jon Hunter >>> >>> For OMAP3+ devices, the clock domains (CLKDMs) support one or more of the >>> following transition modes ... >>> >>> NO_SLEEP (0x0) - A clock domain sleep transition is never initiated, >>> irrespective of the hardware conditions. >>> SW_SLEEP (0x1) - A software-forced sleep transition. The transition is initiated >>> when the associated hardware conditions are satisfied >>> SW_WKUP (0x2) - A software-forced clock domain wake-up transition is initiated, >>> irrespective of the hardware conditions. >>> HW_AUTO (0x3) - Hardware-controlled automatic sleep and wake-up transition is >>> initiated by the PRCM module when the associated hardware >>> conditions are satisfied. >>> >>> For OMAP4 devices, SW_SLEEP is equivalent to HW_AUTO and NO_SLEEP is equivalent >>> to SW_WKUP. For OMAP4 devices, all CLKDMs support HW_AUTO and therefore we can >>> place the CLKDMs in the HW_AUTO state instead of the SW_SLEEP mode. Hence, we >>> do not need to use the SW_SLEEP mode. With regard to NO_SLEEP and SW_WKUP it is >>> preferred to use SW_WKUP mode if the CLKDM supports it and so use this mode >>> instead of NO_SLEEP where possible. >>> >>> For a software perspective the above 4 modes are represented by the following >>> flags to indicate what modes are supported by each of the CLKDMs. >>> >>> CLKDM_CAN_DISABLE_AUTO --> NO_SLEEP >>> CLKDM_CAN_ENABLE_AUTO --> HW_AUTO >>> CLKDM_CAN_FORCE_SLEEP --> SW_SLEEP >>> CLKDM_CAN_FORCE_WAKEUP --> SW_WKUP >>> >>> By eliminating the SW_SLEEP mode the the mapping of the flags for OMAP4 devices >>> can becomes ... >>> >>> CLKDM_CAN_DISABLE_AUTO --> NO_SLEEP >>> CLKDM_CAN_ENABLE_AUTO --> HW_AUTO >>> CLKDM_CAN_FORCE_SLEEP --> HW_AUTO >> Not sure if this can be entirely correct for OMAP4. >> Because HW_AUTO = "Sleep and wakeup transition are >> based upon hardware conditions" >> Where as SW_SLEEP = "Start a software forced sleep >> transition on the domain." >> >> I will reply on the the thread where this is being discussed. > > Given that feedback we received that the only difference between HW_AUTO > and SW_SLEEP is "that the PRM_IRQSTATUS_MPU.TRANSITION_ST interrupt > status is set in case of SW_SLEEP transition, and not set in case of > HW_AUTO transition". Are you ok with this change? If so can you sign-off > on this? Yep I'm OK with that, but Paul is the only one who can sign-off this patch. Reviewed-by: Benoit Cousson Regards, Benoit