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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
parenta89ba0bc02e82920a0f4137aa5d655ac0366cc28 (diff)
downloadop-kernel-dev-4c9337da37c877e53a64696fc8524f642d446cba.zip
op-kernel-dev-4c9337da37c877e53a64696fc8524f642d446cba.tar.gz
[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')
-rw-r--r--drivers/i2c/chips/eeprom.c5
-rw-r--r--drivers/i2c/chips/max6875.c5
-rw-r--r--drivers/i2c/i2c-core.c13
3 files changed, 10 insertions, 13 deletions
diff --git a/drivers/i2c/chips/eeprom.c b/drivers/i2c/chips/eeprom.c
index a27420a..d58403a 100644
--- a/drivers/i2c/chips/eeprom.c
+++ b/drivers/i2c/chips/eeprom.c
@@ -161,11 +161,6 @@ int eeprom_detect(struct i2c_adapter *adapter, int address, int kind)
struct eeprom_data *data;
int err = 0;
- /* prevent 24RF08 corruption */
- if (kind < 0)
- i2c_smbus_xfer(adapter, address, 0, 0, 0,
- I2C_SMBUS_QUICK, NULL);
-
/* There are three ways we can read the EEPROM data:
(1) I2C block reads (faster, but unsupported by most adapters)
(2) Consecutive byte reads (100% overhead)
diff --git a/drivers/i2c/chips/max6875.c b/drivers/i2c/chips/max6875.c
index 31cee2d..9e1aeb6 100644
--- a/drivers/i2c/chips/max6875.c
+++ b/drivers/i2c/chips/max6875.c
@@ -171,11 +171,6 @@ static int max6875_detect(struct i2c_adapter *adapter, int address, int kind)
struct max6875_data *data;
int err = 0;
- /* Prevent 24rf08 corruption (in case of user error) */
- if (kind < 0)
- i2c_smbus_xfer(adapter, address, 0, 0, 0,
- I2C_SMBUS_QUICK, NULL);
-
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE_DATA
| I2C_FUNC_SMBUS_READ_BYTE))
return 0;
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index bee0148..dda472e 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);
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