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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 76EAFC2D0D0 for ; Mon, 23 Dec 2019 12:20:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4B82120828 for ; Mon, 23 Dec 2019 12:20:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577103637; bh=TpJfXPgSRuwL/c72Cja8P/w1/cM3OuXHaibAaaqw+ew=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=J5UGSM2LfKlKg7oBU5hLtz3LDjlT1fGNn4Yaw5MWGkWtwJQM37YQurqqdLwmfqURX SCWD7F7FM0KKyW17jhQPrvSNZBYRYCH8YbMhXsRX+/qDi78xs2hUlAtu7FZ7MNby0t T9p6XuA71bj19YSlqCNolqQtwNZDofMDvBVIShGM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726867AbfLWMUd (ORCPT ); Mon, 23 Dec 2019 07:20:33 -0500 Received: from mail.kernel.org ([198.145.29.99]:43052 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726729AbfLWMUd (ORCPT ); Mon, 23 Dec 2019 07:20:33 -0500 Received: from archlinux (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (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 F1CCF20715; Mon, 23 Dec 2019 12:20:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577103631; bh=TpJfXPgSRuwL/c72Cja8P/w1/cM3OuXHaibAaaqw+ew=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=JomMEZzZX6YYsBuIV6KFhA+Ml0w6SRPZKm+UDwaHVOcfrNwQnfS+TqmTl2ewx7dX+ WjL5ldoyqZ7vC+WdWQVkIky/GioooqdTN28UN6Kir0guVZTC7dw78Sz7tUxXJd5jY6 BEN6u+u3FBfvyI+Qvh6ZUzJxXVnhMJUgJJ2SLTOQ= Date: Mon, 23 Dec 2019 12:20:27 +0000 From: Jonathan Cameron To: Cc: , , , , , , , , , Subject: Re: [PATCH 06/10] iio: adc: at91-sama5d2_adc: handle unfinished conversions Message-ID: <20191223122027.7b93129f@archlinux> In-Reply-To: <1576686157-11939-7-git-send-email-eugen.hristev@microchip.com> References: <1576686157-11939-1-git-send-email-eugen.hristev@microchip.com> <1576686157-11939-7-git-send-email-eugen.hristev@microchip.com> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Wed, 18 Dec 2019 16:24:01 +0000 wrote: > From: Eugen Hristev > > It can happen that on IRQ trigger, not all conversions are done if > we are enabling multiple channels. > The IRQ is triggered on first EOC (end of channel), but it can happen > that not all channels are done. This leads into erroneous reports to > userspace (zero values or previous values). Ouch. That's an unfortunate hardware design. > To solve this, in trigger handler, check if the mask of done channels > is the same as the mask of active scan channels. > If it's the same, proceed and push to buffers. Otherwise, to avoid sleeping > in trigger handler, start a workq that will wait until all channels are > ready. You are fine sleeping in that handler. It's an interrupt thread ;) > Normally, it should happen that in a short time fashion, all channels are > ready, since the first IRQ triggered. > The workq can stall in a loop if a hardware fault happens (for example > the clock suddently dissappears), but if it's a hardware fault then > even exiting the workq won't fix the hardware. > > Signed-off-by: Eugen Hristev > --- > drivers/iio/adc/at91-sama5d2_adc.c | 23 ++++++++++++++++++++++- > 1 file changed, 22 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c > index c575970..a6b4dff 100644 > --- a/drivers/iio/adc/at91-sama5d2_adc.c > +++ b/drivers/iio/adc/at91-sama5d2_adc.c > @@ -8,6 +8,7 @@ > > #include > #include > +#include > #include > #include > #include > @@ -487,6 +488,21 @@ static inline int at91_adc_of_xlate(struct iio_dev *indio_dev, > return at91_adc_chan_xlate(indio_dev, iiospec->args[0]); > } > > +static unsigned int at91_adc_active_scan_mask_to_reg(struct iio_dev *indio_dev) > +{ > + u32 mask = 0; > + u8 bit; > + > + for_each_set_bit(bit, indio_dev->active_scan_mask, > + indio_dev->num_channels) { > + struct iio_chan_spec const *chan = > + at91_adc_chan_get(indio_dev, bit); > + mask |= BIT(chan->channel); > + } > + > + return mask & GENMASK(11, 0); > +} > + > static void at91_adc_config_emr(struct at91_adc_state *st) > { > /* configure the extended mode register */ > @@ -1044,12 +1060,13 @@ static int at91_adc_trigger_handler_nodma(struct iio_dev *indio_dev, > struct iio_poll_func *pf) > { > struct at91_adc_state *st = iio_priv(indio_dev); > + u32 mask = at91_adc_active_scan_mask_to_reg(indio_dev); > > /* > * Check if the conversion is ready. If not, schedule a work to > * check again later. > */ > - if (!(at91_adc_readl(st, AT91_SAMA5D2_ISR) & GENMASK(11, 0))) { > + if ((at91_adc_readl(st, AT91_SAMA5D2_ISR) & mask) != mask) { > schedule_work(&st->workq); > return -EINPROGRESS; > } > @@ -1269,9 +1286,13 @@ static void at91_adc_workq_handler(struct work_struct *workq) > struct at91_adc_state *st = container_of(workq, > struct at91_adc_state, workq); > struct iio_dev *indio_dev = iio_priv_to_dev(st); > + u32 mask = at91_adc_active_scan_mask_to_reg(indio_dev); > > if ((indio_dev->currentmode & INDIO_ALL_TRIGGERED_MODES) && > iio_trigger_validate_own_device(indio_dev->trig, indio_dev)) { > + while ((at91_adc_readl(st, AT91_SAMA5D2_ISR) & mask) != mask) > + udelay(1); > + ok. This fixes the issue raised earlier. Please reorganize the series so we never introduce this code in a broken fashion. + look at doing it in the interrupt thread anyway. Jonathan > at91_adc_read_and_push_channels(indio_dev, st->timestamp); > iio_trigger_notify_done(indio_dev->trig); > } else {