From: Corey Minyard <minyard@acm.org>
To: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>,
linux-i2c@vger.kernel.org,
Andrew Manley <andrew.manley@sealingtech.com>,
linux-kernel@vger.kernel.org, Corey Minyard <cminyard@mvista.com>
Subject: Re: [PATCH 3/3] i2c:imx: Use an hrtimer, not a timer, for checking for bus idle
Date: Wed, 10 Nov 2021 08:45:45 -0600 [thread overview]
Message-ID: <20211110144545.GF4667@minyard.net> (raw)
In-Reply-To: <20211110090338.GE12195@pengutronix.de>
On Wed, Nov 10, 2021 at 10:03:38AM +0100, Oleksij Rempel wrote:
> On Mon, Oct 04, 2021 at 07:32:16PM -0500, minyard@acm.org wrote:
> > From: Corey Minyard <cminyard@mvista.com>
> >
> > The timer is too slow and significantly reduces performance. Use an
> > hrtimer to get things working faster.
> >
> > Signed-off-by: Corey Minyard <minyard@acm.org>
> > Tested-by: Andrew Manley <andrew.manley@sealingtech.com>
> > Reviewed-by: Andrew Manley <andrew.manley@sealingtech.com>
>
> Do we need to keep this change history? If no, please merge it to the
> first patch.
Yeah, I can do that. It make sense.
Thanks,
-corey
>
> > ---
> > 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 <linux/iopoll.h>
> > #include <linux/kernel.h>
> > #include <linux/spinlock.h>
> > -#include <linux/timer.h>
> > +#include <linux/hrtimer.h>
> > #include <linux/module.h>
> > #include <linux/of.h>
> > #include <linux/of_device.h>
> > @@ -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 |
prev parent reply other threads:[~2021-11-10 14:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-05 0:32 [PATCH 0/3] i2c:imx: Deliver a timely stop on slave side, fix recv minyard
2021-10-05 0:32 ` [PATCH 1/3] i2c:imx: Add timer for handling the stop condition minyard
2021-11-01 17:27 ` Corey Minyard
2021-11-10 8:58 ` Oleksij Rempel
2021-10-05 0:32 ` [PATCH 2/3] i2c:imx: Add an extra read at the end of an I2C slave read minyard
2021-11-10 8:58 ` Oleksij Rempel
2021-10-05 0:32 ` [PATCH 3/3] i2c:imx: Use an hrtimer, not a timer, for checking for bus idle minyard
2021-11-02 8:58 ` Uwe Kleine-König
2021-11-02 11:50 ` Corey Minyard
2021-11-10 9:03 ` Oleksij Rempel
2021-11-10 14:45 ` Corey Minyard [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20211110144545.GF4667@minyard.net \
--to=minyard@acm.org \
--cc=andrew.manley@sealingtech.com \
--cc=cminyard@mvista.com \
--cc=kernel@pengutronix.de \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=o.rempel@pengutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).