From: Oleksij Rempel <o.rempel@pengutronix.de>
To: Christian Eggers <ceggers@arri.de>
Cc: "Oleksij Rempel" <linux@rempel-privat.de>,
"Shawn Guo" <shawnguo@kernel.org>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Fabio Estevam" <festevam@gmail.com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"David Laight" <David.Laight@ACULAB.COM>,
linux-kernel@vger.kernel.org,
"Krzysztof Kozlowski" <krzk@kernel.org>,
"NXP Linux Team" <linux-imx@nxp.com>,
"Pengutronix Kernel Team" <kernel@pengutronix.de>,
stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-i2c@vger.kernel.org
Subject: Re: [PATCH v5 2/3] i2c: imx: Check for I2SR_IAL after every byte
Date: Fri, 9 Oct 2020 09:53:35 +0200 [thread overview]
Message-ID: <20201009075335.GC817@pengutronix.de> (raw)
In-Reply-To: <20201007084524.10835-3-ceggers@arri.de>
On Wed, Oct 07, 2020 at 10:45:23AM +0200, Christian Eggers wrote:
> Arbitration Lost (IAL) can happen after every single byte transfer. If
> arbitration is lost, the I2C hardware will autonomously switch from
> master mode to slave. If a transfer is not aborted in this state,
> consecutive transfers will not be executed by the hardware and will
> timeout.
>
> Signed-off-by: Christian Eggers <ceggers@arri.de>
> Tested (not extensively) on Vybrid VF500 (Toradex VF50):
> Tested-by: Krzysztof Kozlowski <krzk@kernel.org>
> Cc: stable@vger.kernel.org
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Thank you!
> ---
> drivers/i2c/busses/i2c-imx.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index cbdcab73a055..63575af41c09 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -490,6 +490,16 @@ static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx, bool atomic)
> dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
> return -ETIMEDOUT;
> }
> +
> + /* check for arbitration lost */
> + if (i2c_imx->i2csr & I2SR_IAL) {
> + dev_dbg(&i2c_imx->adapter.dev, "<%s> Arbitration lost\n", __func__);
> + i2c_imx_clear_irq(i2c_imx, I2SR_IAL);
> +
> + i2c_imx->i2csr = 0;
> + return -EAGAIN;
> + }
> +
> dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__);
> i2c_imx->i2csr = 0;
> return 0;
> --
> Christian Eggers
> Embedded software developer
>
> Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
> Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918
> Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH
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> Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler
>
>
>
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next prev parent reply other threads:[~2020-10-09 7:53 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-07 8:45 [PATCH v5 0/3] i2c: imx: Fix handling of arbitration loss Christian Eggers
2020-10-07 8:45 ` [PATCH v5 1/3] i2c: imx: Fix reset of I2SR_IAL flag Christian Eggers
2020-10-08 9:56 ` Wolfram Sang
2020-10-09 7:11 ` Oleksij Rempel
2020-10-09 7:52 ` Oleksij Rempel
2020-10-07 8:45 ` [PATCH v5 2/3] i2c: imx: Check for I2SR_IAL after every byte Christian Eggers
2020-10-09 7:53 ` Oleksij Rempel [this message]
2020-10-07 8:45 ` [PATCH v5 3/3] i2c: imx: Don't generate STOP condition if arbitration has been lost Christian Eggers
2020-10-09 8:14 ` Oleksij Rempel
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