Hi Jean, > > > 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. Good idea, but the GPIO chip is also used for other totally unrelated functions, so I think a GPIO class would make more sense. Laurent Pinchart
