Re: [PATCH v5 2/3] i2c: imx: Check for I2SR_IAL after every byte
From: Oleksij Rempel <o.rempel@pengutronix.de>
Date: 2020-10-09 07:53:48
Also in:
linux-i2c, lkml, stable
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!
quoted hunk ↗ jump to hunk
--- 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 Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477 Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler
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