On Wed, Feb 08, 2012 at 08:54:29PM +0100, Jean Delvare wrote: > Hi Robin, > > On Wed, 8 Feb 2012 13:46:15 -0600, Robin Holt wrote: > > We are using a Xilinx FPGA which implements a series of i2c bus > > interfaces. We are planning on implementing a single-bit GPIO > > (XIIC_GPO_REG_OFFSET) which is included in that logic block to act > > as a MUX selector (also in the FPGA) between two separate i2c busses. > > > > This will require a GPIO driver in the linux kernel. > > > > Is it better to try and change the i2c-xiic.c code which already knows > > about the GPO register to handle that additional GPIO or should we be > > implementing the GPIO driver outside the i2c driver and then use the > > standard i2c-mux support available in newer kernels? > > Both are possible. It depends if there are other GPIOs on your FPGA > which you will have to access from other drivers for other purposes. If > there are such other GPIOs then it certainly makes sense to have a > clean, separate gpio driver for your FPGA, and have all consumers bind > to it. If not, then I'd keep things simple and embed everything in > i2c-xiic.c, especially if the two i2c buses are truly separated and > there is no common trunk (i2c-mux would create 3 segments.) Do you know of any other examples of an i2c bus interface which provides a built-in general purpose output for MUX selection? I am hoping for some example of the "right" way to do this. Thanks, Robin -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
