From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 194CBC282DA for ; Sun, 3 Feb 2019 14:27:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E8B632082C for ; Sun, 3 Feb 2019 14:27:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730542AbfBCO1K (ORCPT ); Sun, 3 Feb 2019 09:27:10 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:55574 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730149AbfBCOUu (ORCPT ); Sun, 3 Feb 2019 09:20:50 -0500 Received: from cable-78.29.236.164.coditel.net ([78.29.236.164] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gqIdd-0006MQ-4K; Sun, 03 Feb 2019 14:20:49 +0000 Received: from ben by deadeye with local (Exim 4.92-RC4) (envelope-from ) id 1gqI9V-0006r0-6Y; Sun, 03 Feb 2019 14:49:41 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Jonathan Cameron" , "Maxime Ripard" , "Ludovic Desroches" , "Eugen Hristev" Date: Sun, 03 Feb 2019 14:45:08 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 048/305] iio: adc: at91: fix acking DRDY irq on simple conversions In-Reply-To: X-SA-Exim-Connect-IP: 78.29.236.164 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.63-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Eugen Hristev commit bc1b45326223e7e890053cf6266357adfa61942d upstream. When doing simple conversions, the driver did not acknowledge the DRDY irq. If this irq status is not acked, it will be left pending, and as soon as a trigger is enabled, the irq handler will be called, it doesn't know why this status has occurred because no channel is pending, and then it will go int a irq loop and board will hang. To avoid this situation, read the LCDR after a raw conversion is done. Fixes: 0e589d5fb ("ARM: AT91: IIO: Add AT91 ADC driver.") Cc: Maxime Ripard Signed-off-by: Eugen Hristev Acked-by: Ludovic Desroches Signed-off-by: Jonathan Cameron Signed-off-by: Ben Hutchings --- drivers/iio/adc/at91_adc.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/iio/adc/at91_adc.c +++ b/drivers/iio/adc/at91_adc.c @@ -276,6 +276,8 @@ void handle_adc_eoc_trigger(int irq, str iio_trigger_poll(idev->trig, iio_get_time_ns()); } else { st->last_value = at91_adc_readl(st, AT91_ADC_CHAN(st, st->chnb)); + /* Needed to ACK the DRDY interruption */ + at91_adc_readl(st, AT91_ADC_LCDR); st->done = true; wake_up_interruptible(&st->wq_data_avail); }