On Mon, 2020-05-11 at 13:03 +0000, Ardelean, Alexandru wrote: > [External] > > On Mon, 2020-05-11 at 12:37 +0200, Lars-Peter Clausen wrote: > > [External] > > > > On 5/11/20 12:33 PM, Ardelean, Alexandru wrote: > > > On Sun, 2020-05-10 at 11:09 +0100, Jonathan Cameron wrote: > > > > [External] > > > > > > > > On Sat, 9 May 2020 10:52:14 +0200 > > > > Lars-Peter Clausen <lars@xxxxxxxxxx> wrote: > > > > > > > > > On 5/8/20 3:53 PM, Alexandru Ardelean wrote: > > > > > > [...] > > > > > > What I don't like, is that iio:device3 has iio:buffer3:0 (to 3). > > > > > > This is because the 'buffer->dev.parent = &indio_dev->dev'. > > > > > > But I do feel this is correct. > > > > > > So, now I don't know whether to leave it like that or symlink to > > > > > > shorter > > > > > > versions like 'iio:buffer3:Y' -> 'iio:device3/bufferY'. > > > > > > The reason for naming the IIO buffer devices to 'iio:bufferX:Y' is > > > > > > mostly to make the names unique. It would have looked weird to do > > > > > > '/dev/buffer1' if I would have named the buffer devices 'bufferX'. > > > > > > > > > > > > So, now I'm thinking of whether all this is acceptable. > > > > > > Or what is acceptable? > > > > > > Should I symlink 'iio:device3/iio:buffer3:0' -> > > > > > > 'iio:device3/buffer0'? > > > > > > What else should I consider moving forward? > > > > > > What means forward? > > > > > > Where did I leave my beer? > > > > > Looking at how the /dev/ devices are named I think we can provide a > > > > > name > > > > > that is different from the dev_name() of the device. Have a look at > > > > > device_get_devnode() in drivers/base/core.c. We should be able to > > > > > provide the name for the chardev through the devnode() callback. > > > > > > > > > > While we are at this, do we want to move the new devices into an iio > > > > > subfolder? So iio/buffer0:0 instead of iio:buffer0:0? > > > > Possibly on the folder. I can't for the life of me remember why I > > > > decided > > > > not to do that the first time around - I'll leave it at the > > > > mysterious "it may turn out to be harder than you'd think..." > > > > Hopefully not ;) > > > I was also thinking about the /dev/iio subfolder while doing this. > > > I can copy that from /dev/input > > > They seem to do it already. > > > I don't know how difficult it would be. But it looks like a good > > > precedent. > > > > All you have to do is return "iio/..." from the devnode() callback. > > I admit I did not look closely into drivers/input/input.c before mentioning > this > as as good precedent. > > But, I looks like /dev/inpput is a class. > While IIO devices are a bus_type devices. > Should we start implementing an IIO class? or? What I should have highlighted [before] with this, is that there is no devnode() callback for the bus_type [type]. > > > > > My concern regarding going to use stuff from core [like > > > device_get_devnode()] is > > > that it seems to bypass some layers of kernel. > > > If I do 'git grep device_get_devnode', I get: > > > > > > drivers/base/core.c: name = device_get_devnode(dev, &mode, > > > &uid, > > > &gid, &tmp); > > > drivers/base/core.c: * device_get_devnode - path of device node file > > > drivers/base/core.c:const char *device_get_devnode(struct device *dev, > > > drivers/base/devtmpfs.c: req.name = device_get_devnode(dev, > > > &req.mode, > > > &req.uid, &req.gid, &tmp); > > > drivers/base/devtmpfs.c: req.name = device_get_devnode(dev, NULL, > > > NULL, > > > NULL, &tmp); > > > include/linux/device.h:extern const char *device_get_devnode(struct device > > > *dev, > > > (END) > > > > > > So, basically, most uses of device_get_devnode() are in core code, and I > > > feel > > > that this may be sanctioned somewhere by some core people, if I do it. > > > I could be wrong, but if you disagree, I'll take your word for it. > > You are not supposed to use the function itself, you should implement > > the devnode() callback for the IIO bus, which is then used by the core > > device_get_devnode() function. > >
