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authorChris David <cd@chrisdavid.com>2007-10-13 23:56:33 +0200
committerJean Delvare <khali@hyperion.delvare>2007-10-13 23:56:33 +0200
commita202707e71ff16d5e3a92f40eeaa41f3099dd8c5 (patch)
tree7c43b75d4cc52fdf9f3a8a3b08a0b235e8529c24 /drivers/i2c
parent6662cbb989ee71712176570759bdc4e596aed417 (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.c11
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);
}