Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1168154AbcKAI7r (ORCPT ); Tue, 1 Nov 2016 04:59:47 -0400 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:44362 "EHLO metis.ext.4.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1168139AbcKAI7l (ORCPT ); Tue, 1 Nov 2016 04:59:41 -0400 Date: Tue, 1 Nov 2016 09:59:35 +0100 From: Sascha Hauer To: Boris Brezillon Cc: linux-pwm@vger.kernel.org, Bhuvanchandra DV , Lukasz Majewski , linux-kernel@vger.kernel.org, Stefan Agner , Thierry Reding , kernel@pengutronix.de, Fabio Estevam , Philipp Zabel , Fabio Estevam , Lothar Wassmann Subject: Re: [PATCH v2 03/10] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation Message-ID: <20161101085935.4fitl2u6hkt63ro6@pengutronix.de> References: <1477549785-4972-1-git-send-email-l.majewski@majess.pl> <1477549785-4972-4-git-send-email-l.majewski@majess.pl> <20161027094005.2da3b7d4@bbrezillon> <20161031055904.av45k535c26gjonz@pengutronix.de> <20161031092937.im5epytgorcd5fbm@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161031092937.im5epytgorcd5fbm@pengutronix.de> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 09:57:26 up 159 days, 19:21, 37 users, load average: 0.09, 0.05, 0.05 User-Agent: Mutt/1.6.2-neo (2016-06-11) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1598 Lines: 39 On Mon, Oct 31, 2016 at 10:29:37AM +0100, Sascha Hauer wrote: > > accesses. This is true for the ->config() callback, but not for the > > ->set_enable() callback. Given that the ipg clock is not consistently > > enabled for all register accesses we can assume that either it is not > > required at all or that the current code does not work. > > Remove the ipg clock code for now so that it's no longer in the way of > > refactoring the driver. > > For reference: > > I verified on i.MX53 and i.MX25 that the ipg clock provided to the pwm > driver is not needed when accessing registers. I would have to verify > that on i.MX27 aswell, but I do not have a board handy at the moment. Also on i.MX27 disabling the PWMs ipg_clk does not disable register accesses. Sascha > > The current assumption as discussed by Philipp and me is that the ipg > clk is only needed when the pwm output is driven by the ipg clk > (MX3_PWMCR[16:17] = MX3_PWMCR_CLKSRC_IPG) > > Sascha > > -- > Pengutronix e.K. | | > Industrial Linux Solutions | http://www.pengutronix.de/ | > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | > > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |