Hi Rudolf, hi Laurent, > > I'm developping the DSL chipset driver, and the needed arises to control the > > GPIO lines from inside the driver. I've had a look at some PCI drivers which > > need to control I2C devices, and all of them have the I2C chips connected to > > an I2C bus controlled by the PCI device. Getting a reference to those chips > > is thus quite easy. I'm a bit puzzled regarding how to do the same for my > > design. Could anyone advice me on how to get a reference to the PCA9557 from > > the DSL platform driver in a clean way ? > > Well this is a bit problem. There are three ways: > > 1) create EXPORT_SYMBOL(my_api) with defined API and call it from your PCI > device to the PCA driver some RTC drivers did this > > 2) there is, now obsoleted, method with the i2c command callback. This may be > removed in the future. > > 3) create a class interface for this stuff and register the device in the class > I'm taking this aproach to create an watchdog class even for i2c devices... 4) Have a single driver for both the DSL chipset and the GPIO-controlling chip. Given that the GPIO pins usage is specific to your system, reusability isn't an issue. You may make a composite module to keep a clean limit between both parts of the driver. It's mostly similar to option 1), except that you don't even have to define and API and export the symbols. -- Jean Delvare
