diff options
| author | Steve Glendinning <steve.glendinning@smsc.com> | 2009-03-26 08:14:36 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-03-27 08:46:38 +0100 |
| commit | 58add9fc02e7a9dbab9d80d5fa64f13972e91eb5 (patch) | |
| tree | 1bc6efee3a5764a9462eb6d3a9987b1add021bc4 /drivers/net/smsc911x.c | |
| parent | gianfar: fix headroom expansion code (diff) | |
| download | linux-58add9fc02e7a9dbab9d80d5fa64f13972e91eb5.tar.xz linux-58add9fc02e7a9dbab9d80d5fa64f13972e91eb5.zip | |
smsc911x: enforce read-after-write timing restriction on eeprom access
The LAN911x datasheet specifies a minimum delay of 45ns between a write
of E2P_DATA and any read. This patch adds a single dummy read of
BYTE_TEST to enforce this timing constraint.
Signed-off-by: Steve Glendinning <steve.glendinning@smsc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/smsc911x.c')
| -rw-r--r-- | drivers/net/smsc911x.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/net/smsc911x.c b/drivers/net/smsc911x.c index ad3cbc91a8fa..af8f60ca0f57 100644 --- a/drivers/net/smsc911x.c +++ b/drivers/net/smsc911x.c @@ -1680,6 +1680,7 @@ static int smsc911x_eeprom_write_location(struct smsc911x_data *pdata, u8 address, u8 data) { u32 op = E2P_CMD_EPC_CMD_ERASE_ | address; + u32 temp; int ret; SMSC_TRACE(DRV, "address 0x%x, data 0x%x", address, data); @@ -1688,6 +1689,10 @@ static int smsc911x_eeprom_write_location(struct smsc911x_data *pdata, if (!ret) { op = E2P_CMD_EPC_CMD_WRITE_ | address; smsc911x_reg_write(pdata, E2P_DATA, (u32)data); + + /* Workaround for hardware read-after-write restriction */ + temp = smsc911x_reg_read(pdata, BYTE_TEST); + ret = smsc911x_eeprom_send_cmd(pdata, op); } |