From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hunter Subject: Re: [PATCH 5/6] ARM: OMAP4: CLKDM: Update supported transition modes Date: Tue, 15 May 2012 09:33:34 -0500 Message-ID: <4FB2693E.7090303@ti.com> References: <1336599364-11024-1-git-send-email-jon-hunter@ti.com> <4FAB6623.9090005@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from devils.ext.ti.com ([198.47.26.153]:38182 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932355Ab2EOOdl (ORCPT ); Tue, 15 May 2012 10:33:41 -0400 In-Reply-To: <4FAB6623.9090005@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Santosh Shilimkar Cc: linux-omap , Ming Lei , Will Deacon , Benoit Cousson , Paul Walmsley , Kevin Hilman 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? I can update the series with all the comments and re-post this week. Cheers Jon