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=ham 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 61C68C47404 for ; Sat, 5 Oct 2019 15:44:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 324AA222C8 for ; Sat, 5 Oct 2019 15:44:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570290253; bh=MfBPE9ggoRo+pXT+Cqd2AsQZxCxS2f7fC3BRFg5lNHY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=ZQDkMcTQjCebRVPFhLPVhFT75yO174+nW85rwjK8Ls2H57QcDqqhfSVC+C0+77Uk3 0xeXDqDW2LAdhk+iAgKekgAW4F6QZvP1yuwHsgYgm7nxU1T1qPnqa2DyvHR4MeWDwn rIZ6oc+BI5mE8g2ifwVOoI4K1AuLewUFR+TjkqQs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727466AbfJEPoM (ORCPT ); Sat, 5 Oct 2019 11:44:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:33566 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725826AbfJEPoM (ORCPT ); Sat, 5 Oct 2019 11:44:12 -0400 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 035CD20862; Sat, 5 Oct 2019 15:44:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570290251; bh=MfBPE9ggoRo+pXT+Cqd2AsQZxCxS2f7fC3BRFg5lNHY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=KmECbQL+Bz4niLvLUr1kf/5KgHDoZ9GM38/KcddI+5smhwqvmMv5jBV/LMSxeFdh1 hZt/LFskku2dCrzChZfSiNEGOmOSkThsvKul0JyRn06UDl3xIlZdcr9YEunH+HijfH NbUXhRWhZgrcNvXxZ/+hmeDJ/UgwGITl2myv7zUs= Date: Sat, 5 Oct 2019 16:44:05 +0100 From: Jonathan Cameron To: Gwendal Grignou Cc: knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, lee.jones@linaro.org, bleung@chromium.org, enric.balletbo@collabora.com, dianders@chromium.org, groeck@chromium.org, fabien.lahoudere@collabora.com, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org Subject: Re: [PATCH 04/13] platform: chrome: cros-ec: record event timestamp in the hard irq Message-ID: <20191005164405.7e86362f@archlinux> In-Reply-To: <20190922175021.53449-5-gwendal@chromium.org> References: <20190922175021.53449-1-gwendal@chromium.org> <20190922175021.53449-5-gwendal@chromium.org> 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: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Sun, 22 Sep 2019 10:50:12 -0700 Gwendal Grignou wrote: > To improve sensor timestamp precision, given EC and AP are in > different time domains, the AP needs to try to record the exact > moment an event was signalled to the AP by the EC as soon as > possible after it happens. > > First thing in the hard irq is the best place for this. > > Signed-off-by: Gwendal Grignou If this is only going to be used in IIO paths, the there is a control to set which clock is used. This is really a legacy thing due to me once picking a silly default, but we may be causing confusion by having that control but it having no effect. Otherwise looks good to me. > --- > drivers/platform/chrome/cros_ec.c | 18 +++++++++++++++++- > drivers/platform/chrome/cros_ec_lpc.c | 2 ++ > include/linux/platform_data/cros_ec_proto.h | 15 +++++++++++++++ > 3 files changed, 34 insertions(+), 1 deletion(-) > > diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c > index fd77e6fa74c2..f49eb1d1e3cd 100644 > --- a/drivers/platform/chrome/cros_ec.c > +++ b/drivers/platform/chrome/cros_ec.c > @@ -31,6 +31,21 @@ static struct cros_ec_platform pd_p = { > .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX), > }; > > +s64 cros_ec_get_time_ns(void) > +{ > + return ktime_get_boottime_ns(); > +} > +EXPORT_SYMBOL(cros_ec_get_time_ns); > + > +static irqreturn_t ec_irq_handler(int irq, void *data) > +{ > + struct cros_ec_device *ec_dev = data; > + > + ec_dev->last_event_time = cros_ec_get_time_ns(); > + > + return IRQ_WAKE_THREAD; > +} > + > static irqreturn_t ec_irq_thread(int irq, void *data) > { > struct cros_ec_device *ec_dev = data; > @@ -132,7 +147,8 @@ int cros_ec_register(struct cros_ec_device *ec_dev) > } > > if (ec_dev->irq) { > - err = devm_request_threaded_irq(dev, ec_dev->irq, NULL, > + err = devm_request_threaded_irq( > + dev, ec_dev->irq, ec_irq_handler, > ec_irq_thread, IRQF_TRIGGER_LOW | IRQF_ONESHOT, > "chromeos-ec", ec_dev); > if (err) { > diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c > index 7d10d909435f..3c77496e164d 100644 > --- a/drivers/platform/chrome/cros_ec_lpc.c > +++ b/drivers/platform/chrome/cros_ec_lpc.c > @@ -313,6 +313,8 @@ static void cros_ec_lpc_acpi_notify(acpi_handle device, u32 value, void *data) > { > struct cros_ec_device *ec_dev = data; > > + ec_dev->last_event_time = cros_ec_get_time_ns(); > + > if (ec_dev->mkbp_event_supported && > cros_ec_get_next_event(ec_dev, NULL) > 0) > blocking_notifier_call_chain(&ec_dev->event_notifier, 0, > diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h > index e91e3fcb0348..ab12e28f2107 100644 > --- a/include/linux/platform_data/cros_ec_proto.h > +++ b/include/linux/platform_data/cros_ec_proto.h > @@ -121,6 +121,8 @@ struct cros_ec_command { > * @event_data: Raw payload transferred with the MKBP event. > * @event_size: Size in bytes of the event data. > * @host_event_wake_mask: Mask of host events that cause wake from suspend. > + * @last_event_time: exact time from the hard irq when we got notified of > + * a new event. > * @ec: The platform_device used by the mfd driver to interface with the > * main EC. > * @pd: The platform_device used by the mfd driver to interface with the > @@ -161,6 +163,7 @@ struct cros_ec_device { > int event_size; > u32 host_event_wake_mask; > u32 last_resume_result; > + s64 last_event_time; > > /* The platform devices used by the mfd driver */ > struct platform_device *ec; > @@ -308,4 +311,16 @@ int cros_ec_get_next_event(struct cros_ec_device *ec_dev, bool *wake_event); > */ > u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev); > > +/** > + * cros_ec_get_time_ns - Return time in ns. > + * > + * This is the function used to record the time for last_event_time in struct > + * cros_ec_device during the hard irq. > + * > + * This function is probably implemented using ktime_get_boot_ns(), but it's > + * exposed here to make sure all cros_ec drivers use the same code path to get > + * the time. > + */ > +s64 cros_ec_get_time_ns(void); > + > #endif /* __LINUX_CROS_EC_PROTO_H */