Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753528Ab3HERCK (ORCPT ); Mon, 5 Aug 2013 13:02:10 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:39465 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752983Ab3HERCI (ORCPT ); Mon, 5 Aug 2013 13:02:08 -0400 Date: Mon, 5 Aug 2013 18:02:02 +0100 From: "Zubair Lutfullah :" To: Dmitry Torokhov Cc: Jonathan Cameron , Zubair Lutfullah , jic23@cam.ac.uk, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, gregkh@linuxfoundation.org, Russ.Dill@ti.com Subject: Re: [PATCH 1/2] input: ti_tsc: Enable shared IRQ for TSC Message-ID: <20130805170201.GA4310@gmail.com> References: <1374882674-18403-1-git-send-email-zubair.lutfullah@gmail.com> <1374882674-18403-2-git-send-email-zubair.lutfullah@gmail.com> <51FE361B.5030900@kernel.org> <20130805161256.GA8794@core.coreip.homeip.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130805161256.GA8794@core.coreip.homeip.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1803 Lines: 45 On Mon, Aug 05, 2013 at 09:12:56AM -0700, Dmitry Torokhov wrote: > > > Touchscreen and ADC share the same IRQ line from parent MFD core. > > > Previously only Touchscreen was interrupt based. > > > With continuous mode support added in ADC driver, driver requires > > > interrupt to process the ADC samples, so enable shared IRQ flag bit for > > > touchscreen. > > > > > > @@ -260,8 +260,18 @@ static irqreturn_t titsc_irq(int irq, void *dev) > > > unsigned int fsm; > > > > > > + /* > > > + * ADC and touchscreen share the IRQ line. > > > + * FIFO1 threshold, FIFO1 Overrun and FIFO1 underflow > > > + * interrupts are used by ADC, > > > + * hence return from touchscreen IRQ handler if FIFO1 > > > + * related interrupts occurred. > > > + */ > > > + if ((status & IRQENB_FIFO1THRES) || > > > + (status & IRQENB_FIFO1OVRRUN) || > > > + (status & IRQENB_FIFO1UNDRFLW)) > > > + return IRQ_NONE; > > > + else if (status & IRQENB_FIFO0THRES) { > > What happens if both parts have data at the same time? Can both > IRQENB_FIFO1THRES and IRQENB_FIFO0THRES be signalled? What will happen > in this case? If ADC is sampling and someone is touching the TSC, both interrupts can signal so closely that for the purpose of the kernel, they can be seen as signaled together. FIFO 1 used only by ADC and FIFO1THRES handler is inside the iio/adc driver FIFO 0 used only by TSC and FIFO0THRES handler is inside the input/touchscreen Note: These are level interrupts. I would like some input on how to handle such a situation. Thanks Zubair Lutfullah -- 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/