[PATCH 2/3] i2c: imx: Check for I2SR_IAL after every byte
From: Christian Eggers <ceggers@arri.de>
Date: 2020-09-17 12:58:42
Also in:
linux-i2c, lkml, stable
Subsystem:
freescale imx i2c driver, i2c subsystem, i2c subsystem host drivers, the rest · Maintainers:
Oleksij Rempel, Andi Shyti, Linus Torvalds
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> Cc: stable@vger.kernel.org --- drivers/i2c/busses/i2c-imx.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index d8b2e632dd10..9d9b668ec7f2 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c@@ -479,6 +479,20 @@ 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) { + unsigned int temp = i2c_imx->i2csr; + + dev_dbg(&i2c_imx->adapter.dev, "<%s> Arbitration lost\n", __func__); + temp &= ~I2SR_IAL; + temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IAL); + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR); + + 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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