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i2c: Share the I2C device presence detection code

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Use the same I2C device presence detection code for legacy and new
device detection functions. This is more consistent and makes the code
smaller.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Matthieu Castet <castet.matthieu@free.fr>
This commit is contained in:
Jean Delvare 2010-06-03 11:33:51 +02:00
parent 89140f4157
commit 63e4e80218
1 changed files with 40 additions and 40 deletions
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80
drivers/i2c/i2c-core.c
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@ -1277,6 +1277,41 @@ EXPORT_SYMBOL(i2c_master_recv);
* ----------------------------------------------------
*/
/*
* Legacy default probe function, mostly relevant for SMBus. The default
* probe method is a quick write, but it is known to corrupt the 24RF08
* EEPROMs due to a state machine bug, and could also irreversibly
* write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
* we use a short byte read instead. Also, some bus drivers don't implement
* quick write, so we fallback to a byte read in that case too.
* On x86, there is another special case for FSC hardware monitoring chips,
* which want regular byte reads (address 0x73.) Fortunately, these are the
* only known chips using this I2C address on PC hardware.
* Returns 1 if probe succeeded, 0 if not.
*/
static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
{
int err;
union i2c_smbus_data dummy;
#ifdef CONFIG_X86
if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
&& i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
I2C_SMBUS_BYTE_DATA, &dummy);
else
#endif
if ((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50
|| !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
I2C_SMBUS_BYTE, &dummy);
else
err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
I2C_SMBUS_QUICK, NULL);
return err >= 0;
}
static int i2c_detect_address(struct i2c_client *temp_client,
struct i2c_driver *driver)
{
@ -1297,23 +1332,8 @@ static int i2c_detect_address(struct i2c_client *temp_client,
return 0;
/* Make sure there is something at this address */
if (addr == 0x73 && (adapter->class & I2C_CLASS_HWMON)) {
/* Special probe for FSC hwmon chips */
union i2c_smbus_data dummy;
if (i2c_smbus_xfer(adapter, addr, 0, I2C_SMBUS_READ, 0,
I2C_SMBUS_BYTE_DATA, &dummy) < 0)
return 0;
} else {
if (i2c_smbus_xfer(adapter, addr, 0, I2C_SMBUS_WRITE, 0,
I2C_SMBUS_QUICK, NULL) < 0)
return 0;
/* Prevent 24RF08 corruption */
if ((addr & ~0x0f) == 0x50)
i2c_smbus_xfer(adapter, addr, 0, I2C_SMBUS_WRITE, 0,
I2C_SMBUS_QUICK, NULL);
}
if (!i2c_default_probe(adapter, addr))
return 0;
/* Finally call the custom detection function */
memset(&info, 0, sizeof(struct i2c_board_info));
@ -1420,29 +1440,9 @@ i2c_new_probed_device(struct i2c_adapter *adap,
continue;
}
/* Test address responsiveness
The default probe method is a quick write, but it is known
to corrupt the 24RF08 EEPROMs due to a state machine bug,
and could also irreversibly write-protect some EEPROMs, so
for address ranges 0x30-0x37 and 0x50-0x5f, we use a byte
read instead. Also, some bus drivers don't implement
quick write, so we fallback to a byte read it that case
too. */
if ((addr_list[i] & ~0x07) == 0x30
|| (addr_list[i] & ~0x0f) == 0x50
|| !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) {
union i2c_smbus_data data;
if (i2c_smbus_xfer(adap, addr_list[i], 0,
I2C_SMBUS_READ, 0,
I2C_SMBUS_BYTE, &data) >= 0)
break;
} else {
if (i2c_smbus_xfer(adap, addr_list[i], 0,
I2C_SMBUS_WRITE, 0,
I2C_SMBUS_QUICK, NULL) >= 0)
break;
}
/* Test address responsiveness */
if (i2c_default_probe(adap, addr_list[i]))
break;
}
if (addr_list[i] == I2C_CLIENT_END) {