This is a note to let you know that I've just added the patch titled
i2c: imx: Check for I2SR_IAL after every byte
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
i2c-imx-check-for-i2sr_ial-after-every-byte.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1de67a3dee7a279ebe4d892b359fe3696938ec15 Mon Sep 17 00:00:00 2001
From: Christian Eggers <ceggers@xxxxxxx>
Date: Fri, 9 Oct 2020 13:03:19 +0200
Subject: i2c: imx: Check for I2SR_IAL after every byte
From: Christian Eggers <ceggers@xxxxxxx>
commit 1de67a3dee7a279ebe4d892b359fe3696938ec15 upstream.
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@xxxxxxx>
Tested (not extensively) on Vybrid VF500 (Toradex VF50):
Tested-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
Acked-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-imx.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -460,6 +460,16 @@ static int i2c_imx_trx_complete(struct i
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;
Patches currently in stable-queue which might be from ceggers@xxxxxxx are
queue-4.19/i2c-imx-check-for-i2sr_ial-after-every-byte.patch
queue-4.19/i2c-imx-fix-reset-of-i2sr_ial-flag.patch
queue-4.19/i2c-imx-don-t-generate-stop-condition-if-arbitration-has-been-lost.patch
