Messages in this thread Patch in this message | | | From | <> | Subject | [PATCH 1/8] i2c: i2c-bfin-twi: Illegal i2c bus lock upon certain transfer scenarios. | Date | Wed, 16 May 2012 15:20:19 +0800 |
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From: Michael Hennerich <michael.hennerich@analog.com>
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>
git-svn-id: svn://localhost/svn/linux-kernel/trunk@9011 526b6c2d-f592-4532-a319-5dd88ccb003d --- 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 cdb59e5..e6dd3c9 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) { + /* 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 && -- 1.7.0.4
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