From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <55A38D2E.9010500@ti.com> Date: Mon, 13 Jul 2015 13:04:30 +0300 From: Roger Quadros MIME-Version: 1.0 To: Tony Lindgren CC: , , , , , , , Subject: Re: [PATCH 03/12] mtd: nand: omap: Move IRQ handling from GPMC to NAND driver References: <1436531019-18088-1-git-send-email-rogerq@ti.com> <1436531019-18088-4-git-send-email-rogerq@ti.com> <20150713071008.GC26485@atomide.com> In-Reply-To: <20150713071008.GC26485@atomide.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Tony, On 13/07/15 10:10, Tony Lindgren wrote: > * Roger Quadros [150710 05:26]: >> Since the Interrupt Events are used only by the NAND driver, >> there is no point in managing the Interrupt registers >> in the GPMC driver and complicating it with irqchip modeling. > > I don't think it's a good idea to allow external drivers to > tinker directly with GPMC registers. How about just set up GPMC > as an irqchip for the edge detection interrupts? > > I think we already have devices with multiple NAND chips. And > there's nothing stopping other drivers from using the edge > detection interrupts. OK. The GPMC_IRQ registers manage 2 NAND specific interrupts (terminalcount and fifo) and 'n' WAIT pin edge interrupts. So we can model this as a irqchip with 'n + 2' interrupts. We need to take care that if a GPMC chip select needs a wait pin then it can't be used as a generic interrupt. We need to get rid of omap_dev_ready() in nand/omap2.c as it accesses the GPMC_STATUS register directly. Plus it is hard coded to only monitor wait0 pin. What is the best map we should use for irqchip? Some Socs have 4 WAIT pins, some have 3 and some have 2. Should we start with 0,1,2, for the wait pins and use the next available free one for the NAND? cheers, -roger