Hi Michael, On 2005-11-07, Mingkun Gu wrote: > With i2c-dev module, is it possible to have more than one device with > the same major number and different minor numbers? Let say, if I want to > have > > /dev/i2c/0 89 0 > /dev/i2c/1 89 1 > /dev/i2c/2 89 2 > ...... Yes, it is possible. > How can I do it? I tried to insmod the i2c-dev module twice and got > error message say "-1 File exists." The function of i2c-dev is to give userspace an access to existing i2c busses. It doesn't create anything per se. If the only I2C/SMBus you have on your system is the i2c-i801, you'll only have /dev/i2c/0. Note that it is OK to open the same device file twice, if you need to do that. Both sessions will be independant. You need to do that if there are several chips on the bus and you want to drive them all from userspace. > One more thing is whether this module provides the ability to handle > interrupts? The question isn't relevant for i2c-dev, as it doesn't actually drive the hardware. It only acts as a bridge. As for i2c-i801, no, it is poll-based, not interrupt-based. Mark Hoffman had attempted to convert the driver to interrupt-based, but never completed the work. -- Jean Delvare
