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| author |   Michael Hennerich <michael.hennerich@analog.com> | 2012-06-13 16:22:40 +0800 |
|---|---|---|
| committer |   Wolfram Sang <w.sang@pengutronix.de> | 2012-07-13 08:27:31 +0200 |
| commit | 925594e03550f1825647ea5408a32bb9803d90f1 (patch) | |
| tree | debca96175b8e0a36a7265c71722887633fa873c /drivers/i2c | |
| parent | i2c-mv64xxxx: allow more than one driver instance (diff) | |
| download | linux-dev-925594e03550f1825647ea5408a32bb9803d90f1.tar.xz linux-dev-925594e03550f1825647ea5408a32bb9803d90f1.zip | |
i2c: i2c-bfin-twi: Illegal i2c bus lock upon certain transfer scenarios.
For transfer counts > 255 bytes i2c-bfin-twi sets the data
transfer counter DCNT to 0xFF indicating unlimited transfers.
It then uses a flag iface->manual_stop to manually issue the STOP
condition, once the required amount of bytes are received.
We found that on I2C receive operation issuing the STOP condition
together with a FULL RCV FIFO (2bytes) will cause SDA and SCL be
constantly driven low.
Temporary workaround until further investigation:
Discard the RCV FIFO before issuing the STOP condition.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-bfin-twi.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c index 515822429b19..c2e6b7849e8d 100644 --- a/drivers/i2c/busses/i2c-bfin-twi.c +++ b/drivers/i2c/busses/i2c-bfin-twi.c @@ -131,6 +131,10 @@ static void bfin_twi_handle_interrupt(struct bfin_twi_iface *iface, iface->transPtr++; iface->readNum--; } else if (iface->manual_stop) { + /* Temporary workaround to avoid possible bus stall - + * Flush FIFO before issuing the STOP condition + */ + read_RCV_DATA16(iface); write_MASTER_CTL(iface, read_MASTER_CTL(iface) | STOP); } else if (iface->cur_mode == TWI_I2C_MODE_REPEAT && |