Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752590AbaFMHsr (ORCPT ); Fri, 13 Jun 2014 03:48:47 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:50372 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751008AbaFMHsp (ORCPT ); Fri, 13 Jun 2014 03:48:45 -0400 Message-ID: <539AACB9.5080105@ti.com> Date: Fri, 13 Jun 2014 10:48:09 +0300 From: Roger Quadros User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Tony Lindgren CC: , , , , , , , , , , Subject: Re: [PATCH 15/36] ARM: OMAP2+: gpmc: Allow drivers to query GPMC_CLK period References: <1402477001-31132-1-git-send-email-rogerq@ti.com> <1402477001-31132-16-git-send-email-rogerq@ti.com> <20140613072645.GN17845@atomide.com> In-Reply-To: <20140613072645.GN17845@atomide.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/13/2014 10:26 AM, Tony Lindgren wrote: > * Roger Quadros [140611 01:59]: >> GPMC_CLK is the external clock output pin that is used for syncronous >> accesses. >> >> Device drivers need to know the fastest possible GPMC_CLK period in order >> to calculate the most optimal device timings. Add the function >> omap_gpmc_get_clk_period() to allow drivers to get the nearset possible >> (equal to or greater than) GPMC_CLK period given the minimum >> clock period supported by the attached device. >> >> This is especially needed by the onenand driver as it calculates >> device timings on the fly for various onenand speed grades. > > Here too this should probably still be done by the gpmc to driver > glue layer, not by the actual driver that shoud be Linux generic. Well, this is only needed by the omap-onenand driver to perform the timing calculations at run-time. Other option is to model the GPMC_CLK (external) as a clock and request the rate using the clock framework. But since this and the retime() is only used by 2 OMAP specific drivers, I'm not sure if it is worth the effort. cheers, -roger -- 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/