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authorJean Delvare <khali@linux-fr.org>2005-08-09 20:28:10 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2005-09-05 09:14:25 -0700
commit4c9337da37c877e53a64696fc8524f642d446cba (patch)
tree30f34691bd61b55b11ec19f6fbc27ae69886eff8 /drivers/i2c/i2c-core.c
parenta89ba0bc02e82920a0f4137aa5d655ac0366cc28 (diff)
[PATCH] I2C: Centralize 24RF08 corruption prevention
The 24RF08 corruption would better be prevented at i2c-core level than at chip driver level, for several reasons: * The second quick write should happen as soon as possible after the first one, so as to limit the risk that another command is issued on the bus inbetween, causing the corruption. * As a matter of fact, the protection code at driver level was reworked at least three times already, which proves how hard it is to get it right there, while it's straightforward at i2c-core level. * It's easy to add a new driver that would need the protection, and forget to add it. This did happen already. * As additional probing addresses can be passed to most i2c chip drivers as module parameters, virtually every i2c chip driver would need the protection if we want to be really safe. * Why duplicate code when we can easily avoid it? Signed-off-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/i2c/i2c-core.c')
-rw-r--r--drivers/i2c/i2c-core.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index bee0148dfab..dda472e5e8b 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -679,9 +679,16 @@ static int i2c_probe_address(struct i2c_adapter *adapter, int addr, int kind,
return 0;
/* Make sure there is something at this address, unless forced */
- if (kind < 0
- && i2c_smbus_xfer(adapter, addr, 0, 0, 0, I2C_SMBUS_QUICK, NULL) < 0)
- return 0;
+ if (kind < 0) {
+ if (i2c_smbus_xfer(adapter, addr, 0, 0, 0,
+ I2C_SMBUS_QUICK, NULL) < 0)
+ return 0;
+
+ /* prevent 24RF08 corruption */
+ if ((addr & ~0x0f) == 0x50)
+ i2c_smbus_xfer(adapter, addr, 0, 0, 0,
+ I2C_SMBUS_QUICK, NULL);
+ }
/* Finally call the custom detection function */
err = found_proc(adapter, addr, kind);