Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753739AbaBQBri (ORCPT ); Sun, 16 Feb 2014 20:47:38 -0500 Received: from perceval.ideasonboard.com ([95.142.166.194]:58832 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751622AbaBQBrg (ORCPT ); Sun, 16 Feb 2014 20:47:36 -0500 From: Laurent Pinchart To: Magnus Damm Cc: Thomas Gleixner , Laurent Pinchart , SH-Linux , "linux-arm-kernel@lists.infradead.org" , linux-kernel , Daniel Lezcano Subject: Re: [PATCH 11/27] clocksource: sh_cmt: Add support for multiple channels per device Date: Mon, 17 Feb 2014 02:48:42 +0100 Message-ID: <2041255.QOGrHiKJmD@avalon> User-Agent: KMail/4.11.5 (Linux/3.10.25-gentoo; KDE/4.11.5; x86_64; ; ) In-Reply-To: References: <1392339605-20691-1-git-send-email-laurent.pinchart+renesas@ideasonboard.com> <7782053.5pYg74TXhN@avalon> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Magnus, On Monday 17 February 2014 10:41:31 Magnus Damm wrote: > On Mon, Feb 17, 2014 at 3:18 AM, Laurent Pinchart wrote: > > On Saturday 15 February 2014 13:46:54 Thomas Gleixner wrote: > >> On Fri, 14 Feb 2014, Laurent Pinchart wrote: > >> > CMT hardware devices can support multiple channels, with global > >> > registers and per-channel registers. The sh_cmt driver currently models > >> > the hardware with one Linux device per channel. This model makes it > >> > difficult to handle global registers in a clean way. > >> > > >> > Add support for a new model that uses one Linux device per timer with > >> > multiple channels per device. This requires changes to platform data, > >> > add new channel configuration fields. > >> > > >> > Support for the legacy model is kept and will be removed after all > >> > platforms switch to the new model. > >> > > >> > Signed-off-by: Laurent Pinchart > >> > > >> > --- > >> > > >> > drivers/clocksource/sh_cmt.c | 299 ++++++++++++++++++++++++++--------- > >> > include/linux/sh_timer.h | 9 ++ > >> > 2 files changed, 239 insertions(+), 69 deletions(-) > >> > > >> > diff --git a/drivers/clocksource/sh_cmt.c > >> > b/drivers/clocksource/sh_cmt.c > >> > index 5280231..8390f0f 100644 > >> > --- a/drivers/clocksource/sh_cmt.c > >> > +++ b/drivers/clocksource/sh_cmt.c [snip] > >> > @@ -85,11 +94,15 @@ struct sh_cmt_info { > >> > > >> > struct sh_cmt_channel { > >> > struct sh_cmt_device *cmt; > >> > - unsigned int index; > >> > - void __iomem *base; > >> > + unsigned int index; /* Index in the documentation */ > >> > + unsigned int hwidx; /* Real hardware index */ > >> > + > >> > + void __iomem *iostart; > >> > + void __iomem *ioctrl; > >> > > >> > struct irqaction irqaction; > >> > >> While you are at it, can you please get rid of that irqaction and use > >> request_irq() ? > > > > The driver claims it can't use request_irq() because the function is not > > available for early platform devices. If the situation has changed I'd > > gladly get rid of irqaction. > > With the risk of stating the obvious, this depends on how early the > early platform device stuff is being run. The actual location may not > be the same on SH and ARM for instance. > > On ARM we are doing all we can to initialize these devices as late as > ever possible in the MULTIPLAFORM (DT reference) case. Once we manage > to remove the legacy ARM case then there is one less user of early > platform timers. > > One perhaps reasonable way forward could be to use request_irq() in > case of DT and leave the legacy platform data case to rely on > irqaction. The whole point of switching from setup_irq() to request_irq() is to simplify the code. Adding request_irq() as an option would go in the opposite direction. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/