On 26 April 2015 at 13:56, Martin Sperl <ker...@martin.sperl.org> wrote: > >> On 26.04.2015, at 13:23, Hans de Goede <hdego...@redhat.com> wrote: >> I think there is actual a use for just binding spidev as spidev, >> think e.g. the spi pins on the raspberry pi. >> >> How do you deal we suggest with such a situation ? > > I actually asked the same question a few days ago on the spi list > (in thread: "spi: spidev: Warn loudly if instantiated from DT as “spidev”) > and the summary was: > > You can still do as before, but you have to accept that long > irritating warning. > > Or you patch spidev.c to include your pattern of choice for compatiblity
So the suggestion is to add a compatible string like olimex,uext-slot to spidev and use that compatible in the DT? That can certainly be done but adding a new compatible for every board that has some random pins looks like a needless nuisance to me. Especially compared to i2c where you can just open the bus so long as ti is enabled. > > Or you implement the following proposal (which needs a volunteer): >> On 23.04.2015, at 09:42, Geert Uytterhoeven <ge...@linux-m68k.org> wrote: >> >> So what you need is a way to handover from generic spidev to a >> device-specific >> driver, cfr. what graphics drivers do when the device has been bound to by >> vesafb or simplefb. >> >> Could this be implemented in a generic way in the spi or DT code? > > ... >> On 23.04.2015, at 12:36, Mark Brown <broo...@kernel.org> wrote: >> On Thu, Apr 23, 2015 at 09:45:16AM +0200, Geert Uytterhoeven wrote: >> >>> I guess this has been suggested before: the spi core could provide spidev >>> access to all spi client devices which are not bound by a driver? >> >> I don't know if it's been suggested before, certainly nobody did the >> work to make it happen. I don't think I have a massive objection in >> principal. But how do you know there is a device? Devices on i2c can be probed. On spi you just transfer random data and hope it does something useful. Some devices have readable registers and can be probed in a device-specific way but others are write-only. So binding spidev is in my view just saying that you are going to transfer random data from userspace on this bus. Thanks Michal -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
