From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Walmsley Subject: Re: [PATCHv2 2/2] OMAP: add omap_device_reset() Date: Sun, 29 May 2011 20:24:54 -0600 (MDT) Message-ID: References: <1306481908-7386-1-git-send-email-tomi.valkeinen@ti.com> <1306481908-7386-3-git-send-email-tomi.valkeinen@ti.com> <4DDF9B5D.7060408@ti.com> <1306500367.1905.18.camel@deskari> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: Received: from utopia.booyaka.com ([72.9.107.138]:38915 "EHLO utopia.booyaka.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751389Ab1E3CY4 (ORCPT ); Sun, 29 May 2011 22:24:56 -0400 In-Reply-To: <1306500367.1905.18.camel@deskari> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Tomi Valkeinen Cc: "Cousson, Benoit" , "Hilman, Kevin" , "linux-omap@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Hi Tomi, On Fri, 27 May 2011, Tomi Valkeinen wrote: > DSS driver has been designed so that it resets the HW before it begins > programming it. That way we get the HW into known state. Otherwise we > need to be extra careful to program all possible registers to a sane > value. Not impossible, of course, but requires extra work. > > I noticed the problem with DSI driver, it didn't work anymore if I > didn't reset it. One thing that I don't quite understand about this thread is that the hwmod code should be resetting the DSS hwmods when the system boots. Is something not working with this process? That is a separate case from the error recovery case. Sounds like we may need to expose a reset function for that purpose as well. Tomi, I don't think your proposed patch is enough for this, though: we'd also need to reset the hwmod internal state for that module, and reprogram the SYSCONFIG bits, etc. as mach-omap2/omap_hwmod.c:_setup() does. - Paul From mboxrd@z Thu Jan 1 00:00:00 1970 From: paul@pwsan.com (Paul Walmsley) Date: Sun, 29 May 2011 20:24:54 -0600 (MDT) Subject: [PATCHv2 2/2] OMAP: add omap_device_reset() In-Reply-To: <1306500367.1905.18.camel@deskari> References: <1306481908-7386-1-git-send-email-tomi.valkeinen@ti.com> <1306481908-7386-3-git-send-email-tomi.valkeinen@ti.com> <4DDF9B5D.7060408@ti.com> <1306500367.1905.18.camel@deskari> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Tomi, On Fri, 27 May 2011, Tomi Valkeinen wrote: > DSS driver has been designed so that it resets the HW before it begins > programming it. That way we get the HW into known state. Otherwise we > need to be extra careful to program all possible registers to a sane > value. Not impossible, of course, but requires extra work. > > I noticed the problem with DSI driver, it didn't work anymore if I > didn't reset it. One thing that I don't quite understand about this thread is that the hwmod code should be resetting the DSS hwmods when the system boots. Is something not working with this process? That is a separate case from the error recovery case. Sounds like we may need to expose a reset function for that purpose as well. Tomi, I don't think your proposed patch is enough for this, though: we'd also need to reset the hwmod internal state for that module, and reprogram the SYSCONFIG bits, etc. as mach-omap2/omap_hwmod.c:_setup() does. - Paul