diff options
| author | Dirk Eibach <dirk.eibach@gdsys.cc> | 2014-10-29 15:56:44 +0100 |
|---|---|---|
| committer | Heiko Schocher <hs@denx.de> | 2014-11-10 06:44:30 +0100 |
| commit | b97cd6814ec08be56225975a050ee486bfa7c13a (patch) | |
| tree | d62bf2d70db726db65020427cbcb793c5bd2f5aa /drivers/i2c/ppc4xx_i2c.c | |
| parent | 7e78f7ad7f7f666598bc2ff115ea7a35f8e059f1 (diff) | |
ppc4xx: Handle i2c stuck on combined xfer
ppc4xx i2c master gets stuck on errors while repeated start is
active. Can be easily reproduced by "i2c md" on an unpopulated
i2c address. There is not stop condition given, scl remains
pulled low.
The only way out seems to be doing a stop manually and then a
soft reset.
Signed-off-by: Dirk Eibach <dirk.eibach@gdsys.cc>
Reviewed-by: Stefan Roese <sr@denx.de>
Diffstat (limited to 'drivers/i2c/ppc4xx_i2c.c')
| -rw-r--r-- | drivers/i2c/ppc4xx_i2c.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/i2c/ppc4xx_i2c.c b/drivers/i2c/ppc4xx_i2c.c index d2ff86c99a..df8888550b 100644 --- a/drivers/i2c/ppc4xx_i2c.c +++ b/drivers/i2c/ppc4xx_i2c.c @@ -289,6 +289,27 @@ static int _i2c_transfer(struct i2c_adapter *adap, /* Transfer aborted? */ if (status & IIC_EXTSTS_XFRA) result = IIC_NOK_XFRA; + /* Is bus free? + * If error happened during combined xfer + * IIC interface is usually stuck in some strange + * state without a valid stop condition. + * Brute, but working: generate stop, then soft reset. + */ + if ((status & IIC_EXTSTS_BCS_MASK) + != IIC_EXTSTS_BCS_FREE){ + u8 mdcntl = in_8(&i2c->mdcntl); + + /* Generate valid stop condition */ + out_8(&i2c->xtcntlss, IIC_XTCNTLSS_SRST); + out_8(&i2c->directcntl, IIC_DIRCNTL_SCC); + udelay(10); + out_8(&i2c->directcntl, + IIC_DIRCNTL_SCC | IIC_DIRCNTL_SDAC); + out_8(&i2c->xtcntlss, 0); + + ppc4xx_i2c_init(adap, (mdcntl & IIC_MDCNTL_FSM) + ? 400000 : 100000, 0); + } } else if ( status & IIC_STS_PT) { result = IIC_NOK_TOUT; } |