On Sun, 15 Mar 2009, Andy Walls wrote: > On Sun, 2009-03-15 at 18:12 +0100, Jean Delvare wrote: > > > This is the typical multifunction device problem. It isn't specifically > > related to I2C, > > But the specific problem that Hans' brings up is precisely a Linux > kernel I2C subsystem *software* prohibition on two i2c_clients binding > to the same address on the same adapter. For a lot of i2c devices, it would be difficult for two drivers to access the device at the same time without some kind of locking. If you take the reads and writes of one driver and then intersperse the reads and writes of another driver, the resulting sequence from the i2c device's point of view is completely broken. But, I suppose there are some devices where if the drivers all use i2c_smbus_read/write_byte/word_data or equivalent atomic transactions with i2c_transfer(), then you could get away with two drivers talking to the same chip. -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
