FAILED: patch "[PATCH] i2c: recovery: if possible send STOP with recovery pulses" failed to apply to 4.14-stable tree
Subsystems (2)
[email protected]
maintainerThe patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
Quoted 1 line
From
abe41184abac487264a4904bfcff2d5500dccce6Mon Sep 17 00:00:00 2001
From: Wolfram Sang <[email protected]>
Date: Tue, 10 Jul 2018 23:42:15 +0200
Subject: [PATCH] i2c: recovery: if possible send STOP with recovery pulses
I2C clients may misunderstand recovery pulses if they can't read SDA to bail out early. In the worst case, as a write operation. To avoid that and if we can write SDA, try to send STOP to avoid the misinterpretation.
Signed-off-by Wolfram Sang <[email protected]>
Reviewed-by Peter Rosin <[email protected]>
Signed-off-by Wolfram Sang <[email protected]>
drivers/i2c/i2c-core-base.c +10 -1
@@ -198,7 +198,16 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap) val = !val; bri->set_scl (adap, val); -ndelay (RECOVERY_NDELAY ); + +/* +* If we can set SDA, we will always create STOP here to ensure +* the additional pulses will do no harm. This is achieved by +* letting SDA follow SCL half a cycle later. +*/ +ndelay (RECOVERY_NDELAY /2 ); +if (bri->set_sda) + bri->set_sda (adap, val); +ndelay (RECOVERY_NDELAY /2 ); }/* check if recovery actually succeeded */