On Sun, Sep 29, 2013 at 03:11:37PM +0100, Charles Keepax wrote: > There is currently only one other MFD driver (tps65910) which defines > the GPIOs on the main MFD node as we do in the Arizona driver and it > uses the 'hack' that I suggested in my first email of copying the > of_node. > tps65910_gpio->gpio_chip.of_node = tps65910->dev->of_node; Look where it's copying it to - this isn't the hack you were suggesting before. What you were suggesting before was setting the of_node of the child struct device which is a managed thing that the driver core knows about, the device is the owner of the of_node hanging off it. You would end up with the same of_node referenced from two struct devices which isn't clever. The above is putting a pointer into the gpio_chip which is just telling gpiolib that it should use this of_node when it needs one, gpiolib won't try and lifecycle manage the of_node. > Looking around there seem to be quite a few drivers that copy > of_node pointers like this are we sure this isn't an acceptable > solution? I mean the arizona driver we know the components will > always be loaded as part of the MFD and thus will be freed before > the parent node. It's fine to reference an of_node, that's obviously something that will need to happen at some point in order to do anything useful with the data.
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