diff options
Diffstat (limited to 'drivers/i2c/ppc4xx_i2c.c')
| -rw-r--r-- | drivers/i2c/ppc4xx_i2c.c | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/drivers/i2c/ppc4xx_i2c.c b/drivers/i2c/ppc4xx_i2c.c index e7a15ba644..df8888550b 100644 --- a/drivers/i2c/ppc4xx_i2c.c +++ b/drivers/i2c/ppc4xx_i2c.c @@ -158,8 +158,7 @@ static void ppc4xx_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr) * * Typical case is a Write of an addr followd by a Read. The * IBM FAQ does not cover this. On the last byte of the write - * we don't set the creg CHT bit, and on the first bytes of the - * read we set the RPST bit. + * we don't set the creg CHT bit but the RPST bit. * * It does not support address only transfers, there must be * a data part. If you want to write the address yourself, put @@ -247,6 +246,10 @@ static int _i2c_transfer(struct i2c_adapter *adap, if ((!cmd_type && (ptr == addr)) || ((tran + bc) != cnt)) creg |= IIC_CNTL_CHT; + /* last part of address, prepare for repeated start on read */ + if (cmd_type && (ptr == addr) && ((tran + bc) == cnt)) + creg |= IIC_CNTL_RPST; + if (reading) { creg |= IIC_CNTL_READ; } else { @@ -286,6 +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; } @@ -314,8 +338,6 @@ static int _i2c_transfer(struct i2c_adapter *adap, cnt = data_len; tran = 0; reading = cmd_type; - if (reading) - creg = IIC_CNTL_RPST; } } return result; |