This is a note to let you know that I've just added the patch titled
i2c: rcar: fix MNR interrupt handling
to the 3.16-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-rcar-fix-mnr-interrupt-handling.patch
and it can be found in the queue-3.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From dd318b0df27c582ac0d72a346fd6e693700be23c Mon Sep 17 00:00:00 2001
From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Date: Tue, 2 Sep 2014 01:15:26 +0400
Subject: i2c: rcar: fix MNR interrupt handling
From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
commit dd318b0df27c582ac0d72a346fd6e693700be23c upstream.
Sometimes the MNR and MST interrupts happen simultaneously (stop automatically
follows NACK, according to the manuals) and in such case the ID_NACK flag isn't
set since the MST interrupt handling precedes MNR and all interrupts are cleared
and disabled then, so that MNR interrupt is never noticed -- this causes NACK'ed
transfers to be falsely reported as successful. Exchanging MNR and MST handlers
fixes this issue, however the MNR bit somehow gets set again even after being
explicitly cleared, so I decided to completely suppress handling of all disabled
interrupts (which is a good thing anyway)...
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-rcar.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -372,18 +372,15 @@ static irqreturn_t rcar_i2c_irq(int irq,
msr = rcar_i2c_read(priv, ICMSR);
+ /* Only handle interrupts that are currently enabled */
+ msr &= rcar_i2c_read(priv, ICMIER);
+
/* Arbitration lost */
if (msr & MAL) {
rcar_i2c_flags_set(priv, (ID_DONE | ID_ARBLOST));
goto out;
}
- /* Stop */
- if (msr & MST) {
- rcar_i2c_flags_set(priv, ID_DONE);
- goto out;
- }
-
/* Nack */
if (msr & MNR) {
/* go to stop phase */
@@ -393,6 +390,12 @@ static irqreturn_t rcar_i2c_irq(int irq,
goto out;
}
+ /* Stop */
+ if (msr & MST) {
+ rcar_i2c_flags_set(priv, ID_DONE);
+ goto out;
+ }
+
if (rcar_i2c_is_recv(priv))
rcar_i2c_flags_set(priv, rcar_i2c_irq_recv(priv, msr));
else
Patches currently in stable-queue which might be from sergei.shtylyov@xxxxxxxxxxxxxxxxxx are
queue-3.16/revert-i2c-rcar-remove-spinlock.patch
queue-3.16/i2c-rcar-fix-mnr-interrupt-handling.patch
queue-3.16/i2c-rcar-fix-rcar_irq_ack_-recv-send.patch
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