From: Christian Eggers <ceggers@arri.de>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Oleksij Rempel <linux@rempel-privat.de>,
Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
Fabio Estevam <festevam@gmail.com>,
<linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>,
NXP Linux Team <linux-imx@nxp.com>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
<linux-arm-kernel@lists.infradead.org>,
<linux-i2c@vger.kernel.org>
Subject: Re: [PATCH 1/3] i2c: imx: Fix reset of I2SR_IAL flag
Date: Thu, 17 Sep 2020 16:13:50 +0200 [thread overview]
Message-ID: <16013235.tl8pWZfNaG@n95hx1g2> (raw)
In-Reply-To: <20200917140235.igfq2hq63f4qqhrr@pengutronix.de>
Hello Uwe,
On Thursday, 17 September 2020, 16:02:35 CEST, Uwe Kleine-König wrote:
> Hello,
>
> On Thu, Sep 17, 2020 at 02:20:27PM +0200, Christian Eggers wrote:
> ...
> > /* check for arbitration lost */
> > if (temp & I2SR_IAL) {
> > temp &= ~I2SR_IAL;
> > + temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IAL);
> > imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
> > return -EAGAIN;
> ...
> This looks strange. First the flag is cleared and then it is (in some
> cases) set again.
i.MX controllers require writing a 0 to clear these bits. Vybrid controllers
need writing a 1 for the same.
> If I2SR_IIF is set in temp you ack this irq without handling it. (Which
> might happen if atomic is set and irqs are off?!)
This patch is only about using the correct processor specific value for
acknowledging an IRQ... But I think that returning EAGAIN (which aborts the
transfer) should be handling enough. At the next transfer, the controller will
be set back to master mode.
> I see this idiom is used in a few more places in the driver already, I
> didn't check but these might have the same problem maybe?
Best regards
Christian
WARNING: multiple messages have this Message-ID (diff)
From: Christian Eggers <ceggers@arri.de>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
Oleksij Rempel <linux@rempel-privat.de>,
NXP Linux Team <linux-imx@nxp.com>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Fabio Estevam <festevam@gmail.com>,
linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org
Subject: Re: [PATCH 1/3] i2c: imx: Fix reset of I2SR_IAL flag
Date: Thu, 17 Sep 2020 16:13:50 +0200 [thread overview]
Message-ID: <16013235.tl8pWZfNaG@n95hx1g2> (raw)
In-Reply-To: <20200917140235.igfq2hq63f4qqhrr@pengutronix.de>
Hello Uwe,
On Thursday, 17 September 2020, 16:02:35 CEST, Uwe Kleine-König wrote:
> Hello,
>
> On Thu, Sep 17, 2020 at 02:20:27PM +0200, Christian Eggers wrote:
> ...
> > /* check for arbitration lost */
> > if (temp & I2SR_IAL) {
> > temp &= ~I2SR_IAL;
> > + temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IAL);
> > imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
> > return -EAGAIN;
> ...
> This looks strange. First the flag is cleared and then it is (in some
> cases) set again.
i.MX controllers require writing a 0 to clear these bits. Vybrid controllers
need writing a 1 for the same.
> If I2SR_IIF is set in temp you ack this irq without handling it. (Which
> might happen if atomic is set and irqs are off?!)
This patch is only about using the correct processor specific value for
acknowledging an IRQ... But I think that returning EAGAIN (which aborts the
transfer) should be handling enough. At the next transfer, the controller will
be set back to master mode.
> I see this idiom is used in a few more places in the driver already, I
> didn't check but these might have the same problem maybe?
Best regards
Christian
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-09-17 14:57 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-17 12:20 [PATCH 0/3] i2c: imx: Fix handling of arbitration loss Christian Eggers
2020-09-17 12:20 ` Christian Eggers
2020-09-17 12:20 ` [PATCH 1/3] i2c: imx: Fix reset of I2SR_IAL flag Christian Eggers
2020-09-17 12:20 ` Christian Eggers
2020-09-17 14:02 ` Uwe Kleine-König
2020-09-17 14:02 ` Uwe Kleine-König
2020-09-17 14:13 ` Christian Eggers [this message]
2020-09-17 14:13 ` Christian Eggers
2020-09-25 8:11 ` Uwe Kleine-König
2020-09-25 8:11 ` Uwe Kleine-König
2020-10-02 8:01 ` Christian Eggers
2020-10-02 8:01 ` Christian Eggers
2020-10-02 10:21 ` Uwe Kleine-König
2020-10-02 10:21 ` Uwe Kleine-König
2020-09-17 12:20 ` [PATCH 2/3] i2c: imx: Check for I2SR_IAL after every byte Christian Eggers
2020-09-17 12:20 ` Christian Eggers
2020-09-17 12:20 ` [PATCH 3/3] i2c: imx: Don't generate STOP condition if arbitration has been lost Christian Eggers
2020-09-17 12:20 ` Christian Eggers
2020-09-25 7:03 ` [PATCH 0/3] i2c: imx: Fix handling of arbitration loss Oleksij Rempel
2020-09-25 7:03 ` Oleksij Rempel
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=16013235.tl8pWZfNaG@n95hx1g2 \
--to=ceggers@arri.de \
--cc=festevam@gmail.com \
--cc=kernel@pengutronix.de \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-imx@nxp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@rempel-privat.de \
--cc=s.hauer@pengutronix.de \
--cc=shawnguo@kernel.org \
--cc=stable@vger.kernel.org \
--cc=u.kleine-koenig@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.