diff options
| author | Chris David <cd@chrisdavid.com> | 2007-10-13 23:56:33 +0200 |
|---|---|---|
| committer | Jean Delvare <khali@hyperion.delvare> | 2007-10-13 23:56:33 +0200 |
| commit | a202707e71ff16d5e3a92f40eeaa41f3099dd8c5 (patch) | |
| tree | 7c43b75d4cc52fdf9f3a8a3b08a0b235e8529c24 /drivers/i2c | |
| parent | 6662cbb989ee71712176570759bdc4e596aed417 (diff) | |
i2c-au1550: Fix a misused register problem
Fix a "mis-used register" problem on the AMD MIPS Alchemy au1550
I2C interface.
In summary, the programmable serial controller seems to hang the kernel
when I send a single 'address' byte on the I2C bus. The patch
essentially uses the PSC_SMBSTAT register's TE (transmit FIFO empty)
bit to check when the transmit FIFO is empty, instead of using the
PSC_SMBEVNT register's TU (transmit underflow) bit. Using the TE bit
fixed the hang problem.
Signed-off-by: Chris David <cd@chrisdavid.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-au1550.c | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/drivers/i2c/busses/i2c-au1550.c b/drivers/i2c/busses/i2c-au1550.c index d7e7c359fc36..2f684166c43d 100644 --- a/drivers/i2c/busses/i2c-au1550.c +++ b/drivers/i2c/busses/i2c-au1550.c @@ -48,17 +48,14 @@ wait_xfer_done(struct i2c_au1550_data *adap) sp = (volatile psc_smb_t *)(adap->psc_base); - /* Wait for Tx FIFO Underflow. + /* Wait for Tx Buffer Empty */ for (i = 0; i < adap->xfer_timeout; i++) { - stat = sp->psc_smbevnt; + stat = sp->psc_smbstat; au_sync(); - if ((stat & PSC_SMBEVNT_TU) != 0) { - /* Clear it. */ - sp->psc_smbevnt = PSC_SMBEVNT_TU; - au_sync(); + if ((stat & PSC_SMBSTAT_TE) != 0) return 0; - } + udelay(1); } |