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i2c: rcar: fix MNR interrupt handling

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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@cogentembedded.com>
Cc: stable@vger.kernel.org
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Sergei Shtylyov 2014-09-02 01:15:26 +04:00 committed by Wolfram Sang
parent 69e273c0b0
commit dd318b0df2
1 changed files with 9 additions and 6 deletions
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15
drivers/i2c/busses/i2c-rcar.c
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@ -367,18 +367,15 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
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 */
@ -388,6 +385,12 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
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