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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0D80C433F5 for ; Wed, 10 Nov 2021 09:03:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C97296113D for ; Wed, 10 Nov 2021 09:03:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230410AbhKJJGb (ORCPT ); Wed, 10 Nov 2021 04:06:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229931AbhKJJGa (ORCPT ); Wed, 10 Nov 2021 04:06:30 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ABB77C061766 for ; Wed, 10 Nov 2021 01:03:43 -0800 (PST) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mkjW7-000290-Em; Wed, 10 Nov 2021 10:03:39 +0100 Received: from ore by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1mkjW6-0001Zp-F1; Wed, 10 Nov 2021 10:03:38 +0100 Date: Wed, 10 Nov 2021 10:03:38 +0100 From: Oleksij Rempel To: minyard@acm.org Cc: Pengutronix Kernel Team , linux-i2c@vger.kernel.org, Andrew Manley , linux-kernel@vger.kernel.org, Corey Minyard Subject: Re: [PATCH 3/3] i2c:imx: Use an hrtimer, not a timer, for checking for bus idle Message-ID: <20211110090338.GE12195@pengutronix.de> References: <20211005003216.2670632-1-minyard@acm.org> <20211005003216.2670632-4-minyard@acm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20211005003216.2670632-4-minyard@acm.org> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 09:59:29 up 265 days, 12:23, 138 users, load average: 0.22, 0.17, 0.17 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 04, 2021 at 07:32:16PM -0500, minyard@acm.org wrote: > From: Corey Minyard > > The timer is too slow and significantly reduces performance. Use an > hrtimer to get things working faster. > > Signed-off-by: Corey Minyard > Tested-by: Andrew Manley > Reviewed-by: Andrew Manley Do we need to keep this change history? If no, please merge it to the first patch. > --- > drivers/i2c/busses/i2c-imx.c | 23 +++++++++++++++-------- > 1 file changed, 15 insertions(+), 8 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c > index 26a04dc0590b..4b0e9d1784dd 100644 > --- a/drivers/i2c/busses/i2c-imx.c > +++ b/drivers/i2c/busses/i2c-imx.c > @@ -38,7 +38,7 @@ > #include > #include > #include > -#include > +#include > #include > #include > #include > @@ -53,6 +53,8 @@ > /* This will be the driver name the kernel reports */ > #define DRIVER_NAME "imx-i2c" > > +#define I2C_IMX_CHECK_DELAY 30000 /* Time to check for bus idle, in NS */ > + > /* > * Enable DMA if transfer byte size is bigger than this threshold. > * As the hardware request, it must bigger than 4 bytes.\ > @@ -214,8 +216,8 @@ struct imx_i2c_struct { > enum i2c_slave_event last_slave_event; > > /* For checking slave events. */ > - spinlock_t slave_lock; > - struct timer_list slave_timer; > + spinlock_t slave_lock; > + struct hrtimer slave_timer; > }; > > static const struct imx_i2c_hwdata imx1_i2c_hwdata = { > @@ -783,13 +785,16 @@ static irqreturn_t i2c_imx_slave_handle(struct imx_i2c_struct *i2c_imx, > } > > out: > - mod_timer(&i2c_imx->slave_timer, jiffies + 1); > + hrtimer_try_to_cancel(&i2c_imx->slave_timer); > + hrtimer_forward_now(&i2c_imx->slave_timer, I2C_IMX_CHECK_DELAY); > + hrtimer_restart(&i2c_imx->slave_timer); > return IRQ_HANDLED; > } > > -static void i2c_imx_slave_timeout(struct timer_list *t) > +static enum hrtimer_restart i2c_imx_slave_timeout(struct hrtimer *t) > { > - struct imx_i2c_struct *i2c_imx = from_timer(i2c_imx, t, slave_timer); > + struct imx_i2c_struct *i2c_imx = container_of(t, struct imx_i2c_struct, > + slave_timer); > unsigned int ctl, status; > unsigned long flags; > > @@ -798,6 +803,7 @@ static void i2c_imx_slave_timeout(struct timer_list *t) > ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > i2c_imx_slave_handle(i2c_imx, status, ctl); > spin_unlock_irqrestore(&i2c_imx->slave_lock, flags); > + return HRTIMER_NORESTART; > } > > static void i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx) > @@ -1423,7 +1429,8 @@ static int i2c_imx_probe(struct platform_device *pdev) > return -ENOMEM; > > spin_lock_init(&i2c_imx->slave_lock); > - timer_setup(&i2c_imx->slave_timer, i2c_imx_slave_timeout, 0); > + hrtimer_init(&i2c_imx->slave_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); > + i2c_imx->slave_timer.function = i2c_imx_slave_timeout; > > match = device_get_match_data(&pdev->dev); > if (match) > @@ -1538,7 +1545,7 @@ static int i2c_imx_remove(struct platform_device *pdev) > if (ret < 0) > return ret; > > - del_timer_sync(&i2c_imx->slave_timer); > + hrtimer_cancel(&i2c_imx->slave_timer); > > /* remove adapter */ > dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n"); > -- > 2.25.1 > > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |