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=-15.5 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_2 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 11BB5C4320E for ; Mon, 30 Aug 2021 14:29:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBD6260F57 for ; Mon, 30 Aug 2021 14:29:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237672AbhH3OaP convert rfc822-to-8bit (ORCPT ); Mon, 30 Aug 2021 10:30:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:39000 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237205AbhH3OaO (ORCPT ); Mon, 30 Aug 2021 10:30:14 -0400 Received: from jic23-huawei (cpc108967-cmbg20-2-0-cust86.5-4.cable.virginm.net [81.101.6.87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3EA0360F4B; Mon, 30 Aug 2021 14:29:17 +0000 (UTC) Date: Mon, 30 Aug 2021 15:32:27 +0100 From: Jonathan Cameron To: "Sa, Nuno" Cc: Miquel Raynal , Lars-Peter Clausen , Thomas Petazzoni , "linux-iio@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 14/16] iio: adc: max1027: Consolidate the end of conversion helper Message-ID: <20210830153227.7f5809d1@jic23-huawei> In-Reply-To: References: <20210818111139.330636-1-miquel.raynal@bootlin.com> <20210818111139.330636-15-miquel.raynal@bootlin.com> <20210830113716.1f7cdc6f@jic23-huawei> X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 30 Aug 2021 12:44:48 +0000 "Sa, Nuno" wrote: > > -----Original Message----- > > From: Jonathan Cameron > > Sent: Monday, August 30, 2021 12:37 PM > > To: Miquel Raynal > > Cc: Lars-Peter Clausen ; Thomas Petazzoni > > ; linux-iio@vger.kernel.org; linux- > > kernel@vger.kernel.org > > Subject: Re: [PATCH 14/16] iio: adc: max1027: Consolidate the end of > > conversion helper > > > > On Wed, 18 Aug 2021 13:11:37 +0200 > > Miquel Raynal wrote: > > > > > Now that we have a dedicated handler for End Of Conversion > > interrupts, > > > let's create a second path: > > > - Situation 1: we are using the external hardware trigger, a > > conversion > > > has been triggered and the ADC pushed the data to its FIFO, we > > need to > > > retrieve the data and push it to the IIO buffers. > > > - Situation 2: we are not using the external hardware trigger, hence > > we > > > are likely waiting in a blocked thread waiting for this interrupt to > > > happen: in this case we just wake up the waiting thread. > > > > > > Signed-off-by: Miquel Raynal > > > --- > > > drivers/iio/adc/max1027.c | 20 +++++++++++++++++--- > > > 1 file changed, 17 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c > > > index 8d86e77fb5db..8c5995ae59f2 100644 > > > --- a/drivers/iio/adc/max1027.c > > > +++ b/drivers/iio/adc/max1027.c > > > @@ -235,6 +235,7 @@ struct max1027_state { > > > struct iio_trigger *trig; > > > __be16 *buffer; > > > struct mutex lock; > > > + bool data_rdy; > > > bool cnvst_trigger; > > > u8 reg ____cacheline_aligned; > > > }; > > > @@ -243,12 +244,22 @@ static > > DECLARE_WAIT_QUEUE_HEAD(max1027_queue); > > > > > > static int max1027_wait_eoc(struct iio_dev *indio_dev) > > > { > > > + struct max1027_state *st = iio_priv(indio_dev); > > > unsigned int conversion_time = > > MAX1027_CONVERSION_UDELAY; > > > + int ret; > > > > > > - if (indio_dev->active_scan_mask) > > > - conversion_time *= hweight32(*indio_dev- > > >active_scan_mask); > > > + if (st->spi->irq) { > > > + ret = > > wait_event_interruptible_timeout(max1027_queue, > > > + st->data_rdy, HZ / > > 1000); > > > + st->data_rdy = false; > > > + if (ret == -ERESTARTSYS) > > > + return ret; > > > + } else { > > > + if (indio_dev->active_scan_mask) > > > + conversion_time *= hweight32(*indio_dev- > > >active_scan_mask); > > > > > > - usleep_range(conversion_time, conversion_time * 2); > > > + usleep_range(conversion_time, conversion_time * 2); > > > + } > > > > > > return 0; > > > } > > > @@ -481,6 +492,9 @@ static irqreturn_t > > max1027_eoc_irq_handler(int irq, void *private) > > > if (st->cnvst_trigger) { > > > ret = max1027_read_scan(indio_dev); > > > iio_trigger_notify_done(indio_dev->trig); > > > + } else { > > > + st->data_rdy = true; > > > + wake_up(&max1027_queue); > > > > I can't see why a queue is appropriate for this. Use a completion and > > have > > one per instance of the device. No need for the flag etc in that case as > > complete() means we have had an interrupt. > > > > In the case that 'st-> cnvst_trigger' is not set but the spi IRQ > is present, we will wait until we get 'wake_up()' called from here. I wonder if > that is a good idea as the device own trigger is not being used. FWIW, I think this > sync logic is a bit confusing... I would still use the normal trigger infrastructure > ('iio_trigger_generic_data_rdy_poll()') and use the 'cnvst_trigger' flag in the > trigger handler to manually start conversions + wait till eoc. But I might be missing > something though. > > Regarding this handler, I just realized that this is the hard IRQ handler which > might end up calling 'max1027_read_scan()' which in turn calls 'spi_read()'. Am I > missing something here? Good point. This will need to be the threaded handler if done like this. J > > - Nuno Sá