Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756849Ab3GQR1V (ORCPT ); Wed, 17 Jul 2013 13:27:21 -0400 Received: from mail-ea0-f175.google.com ([209.85.215.175]:35395 "EHLO mail-ea0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755889Ab3GQR1O (ORCPT ); Wed, 17 Jul 2013 13:27:14 -0400 From: Zubair Lutfullah To: jic23@cam.ac.uk Cc: linux-iio@vger.kernel.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, koen@dominion.thruhere.net, zubair.lutfullah@gmail.com Subject: [PATCH 11/21] iio: ti_adc: Avoid double threshold event Date: Wed, 17 Jul 2013 18:26:40 +0100 Message-Id: <1374082010-28095-12-git-send-email-zubair.lutfullah@gmail.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1374082010-28095-1-git-send-email-zubair.lutfullah@gmail.com> References: <1374082010-28095-1-git-send-email-zubair.lutfullah@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2020 Lines: 61 The threshold event handler is being called before the FIFO has actually reached the threshold. The current code receives a FIFO threshold event, masks the interrupt, clears the event, and schedules a workqueue. The workqueue is run, it empties the FIFO, and unmasks the interrupt. In the above sequence, after the event is cleared, it immediately retriggers since the FIFO remains beyond the threshold. When the IRQ is unmasked, this triggered event generates another IRQ. However, as the FIFO has just been emptied, it is likely to not contain enough samples. The waits to clear the event until the FIFO has actually been emptied, in the workqueue. The unmasking and masking of the interrupt remains unchanged. Signed-off-by: Russ Dill Signed-off-by: Zubair Lutfullah --- drivers/iio/adc/ti_am335x_adc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c index e510da7..fcd414d 100644 --- a/drivers/iio/adc/ti_am335x_adc.c +++ b/drivers/iio/adc/ti_am335x_adc.c @@ -193,8 +193,7 @@ static irqreturn_t tiadc_irq(int irq, void *private) } else { wake_up_interruptible(&adc_dev->wq_data_avail); } - tiadc_writel(adc_dev, REG_IRQSTATUS, - IRQENB_FIFO1THRES); + return IRQ_HANDLED; } else { return IRQ_NONE; @@ -230,6 +229,8 @@ static void tiadc_poll_handler(struct work_struct *work_s) } buffer->access->store_to(buffer, (u8 *) iBuf); + tiadc_writel(adc_dev, REG_IRQSTATUS, + IRQENB_FIFO1THRES); tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES); -- 1.7.9.5 -- 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/