From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751439AbdAYJQi (ORCPT ); Wed, 25 Jan 2017 04:16:38 -0500 Received: from mx0b-001ae601.pphosted.com ([67.231.152.168]:52778 "EHLO mx0b-001ae601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751360AbdAYJQd (ORCPT ); Wed, 25 Jan 2017 04:16:33 -0500 Authentication-Results: ppops.net; spf=none smtp.mailfrom=ckeepax@opensource.wolfsonmicro.com Date: Wed, 25 Jan 2017 09:17:28 +0000 From: Charles Keepax To: Chanwoo Choi CC: , , Subject: Re: [PATCH] extcon: arizona: Wait for any running HPDETs to complete on jack removal Message-ID: <20170125091728.GB1754@localhost.localdomain> References: <1485253044-22795-1-git-send-email-ckeepax@opensource.wolfsonmicro.com> <5887F8B8.60409@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5887F8B8.60409@samsung.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1701250091 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 25, 2017 at 10:00:40AM +0900, Chanwoo Choi wrote: > Hi Charles, > > On 2017년 01월 24일 19:17, Charles Keepax wrote: > > As the HPDET can't be aborted mid way through we should not allow any new > > insertion to be processed until the previous HPDET has finished. It is very > > unlikely but with low enough debounce settings you could start a new HPDET > > before the old one has completed, which results in an erroneous reading. > > > > Signed-off-by: Charles Keepax > > --- > > drivers/extcon/extcon-arizona.c | 35 +++++++++++++++++++++++++++++++++++ > > 1 file changed, 35 insertions(+) > > > > diff --git a/drivers/extcon/extcon-arizona.c b/drivers/extcon/extcon-arizona.c > > index ed78b7c..218e378 100644 > > --- a/drivers/extcon/extcon-arizona.c > > +++ b/drivers/extcon/extcon-arizona.c > > @@ -1049,6 +1049,39 @@ static void arizona_hpdet_work(struct work_struct *work) > > mutex_unlock(&info->lock); > > } > > > > +static int arizona_hpdet_wait(struct arizona_extcon_info *info) > > +{ > > + struct arizona *arizona = info->arizona; > > + unsigned int val; > > + int i, ret; > > + > > + for (i = 0; i < 15; i++) { > > I recommend that you define the separate constant definition > instead of using interger value (15) directly as following: > > #define HPDET_WAIT_COUNT 15 > > > + ret = regmap_read(arizona->regmap, ARIZONA_HEADPHONE_DETECT_2, > > + &val); > > + if (ret) { > > + dev_err(arizona->dev, > > + "Failed to read HPDET state: %d\n", ret); > > + return ret; > > + } > > + > > + switch (info->hpdet_ip_version) { > > + case 0: > > + if (val & ARIZONA_HP_DONE) > > + return 0; > > + break; > > + default: > > + if (val & ARIZONA_HP_DONE_B) > > + return 0; > > + break; > > + } > > + > > + msleep(20); > > ditto. > > #define HPDET_WAIT_DELAY_MS 20 > Yeah can do. > > + } > > + > > + dev_err(arizona->dev, "HPDET did not appear to complete\n"); > > + return -ETIMEDOUT; > > +} > > + > > static irqreturn_t arizona_jackdet(int irq, void *data) > > { > > struct arizona_extcon_info *info = data; > > @@ -1155,6 +1188,8 @@ static irqreturn_t arizona_jackdet(int irq, void *data) > > "Removal report failed: %d\n", ret); > > } > > > > Sometimes I met this similiar case on specific h/w. > I agree to add some delay according to the h/w. > So, you better to add the detailed comment before > calling the arizona_hpdet_wait() to make it easy > to understand why it is necessary. > > > + arizona_hpdet_wait(info); > No problem to add a comment. > Is not necessary to check the return value of this call? > When arizona_hpdet_wait() return the -ETIMEDOUT, > Does not this error affect the next some code? > I included a return value for completeness sake and incase the function gets reused in other places in the future. But at that point I don't think there is really any action we can take if that call fails, that part of the code relates to the jack being removed so we still need to take all those actions. We can only really log that the failure happened in the kernel log which it already does. Thanks, Charles > > + > > > regmap_update_bits(arizona->regmap, > > ARIZONA_JACK_DETECT_DEBOUNCE, > > ARIZONA_MICD_CLAMP_DB | ARIZONA_JD1_DB, > > > -- > Best Regards, > Chanwoo Choi > Samsung Electronics