Messages in this thread |  | | | Date | Mon, 11 Jun 2012 18:24:47 +0200 | | From | Wolfram Sang <> | | Subject | Re: [PATCH 1/8] i2c: i2c-bfin-twi: Illegal i2c bus lock upon certain transfer scenarios. |
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On Wed, May 16, 2012 at 03:20:19PM +0800, sonic.zhang@analog.com wrote: > 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
Please remove this line.
> --- > 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);
Please mention that this is currently only a workaround, so people know there could be still a proper solution.
> 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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