From mboxrd@z Thu Jan 1 00:00:00 1970 From: plagnioj@jcrosoft.com (Jean-Christophe PLAGNIOL-VILLARD) Date: Tue, 25 Jan 2011 02:44:28 +0100 Subject: [PATCH 2/4] arch/arm/mach-at91/clock.c: Add missing IS_ERR test In-Reply-To: <20110124232302.GQ24104@n2100.arm.linux.org.uk> References: <20110124200515.GA30963@albatros> <4D3DDD07.1030809@bluewatersys.com> <4D3DE35B.1030102@bluewatersys.com> <4D3DE9CD.2040800@bluewatersys.com> <4D3DF46A.1030009@bluewatersys.com> <20110124232302.GQ24104@n2100.arm.linux.org.uk> Message-ID: <20110125014428.GO24284@game.jcrosoft.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 23:23 Mon 24 Jan , Russell King - ARM Linux wrote: > On Tue, Jan 25, 2011 at 10:51:38AM +1300, Ryan Mallon wrote: > > You could, but it would not be helpful. Clock associations are used so > > that _different_ devices can have the same function and map to the > > correct clock. This is used when there are multiple instances of a > > single peripheral. For example, the uart clocks work like this: > > > > at91_clock_associate("usart1_clk", &pdev->dev, "usart"); > > > > so then you can do this in a driver: > > > > uart_clk = clk_get(&pdev->dev, "usart"); > > > > Rather than: > > > > uart_clk = clk_get(NULL, "usart1_clk"); > > > > The former will find the correct uart clock for the device. Because each > > uart is a separate device the correct clock will be selected for each uart. > > > > My point was that there should be no overlap between clk->name and > > clk->function otherwise clk_get will not be able to return the correct > > clock. > > It would be nice if AT91 could switch over to using clkdev at some > point, which greatly helps with associating struct clk's with their > device/function names - and reduces the amount of "different" code. I working on it that's was one of the reason I move clkdev to drivers as AT91 and AVR32 need to switch Best Regards, J.