On 11/15/2012 07:03 AM, Linus Walleij wrote: > On Tue, Nov 13, 2012 at 7:35 AM, Mark Brown > <broo...@opensource.wolfsonmicro.com> wrote: >> On Mon, Nov 12, 2012 at 01:21:40PM -0700, Stephen Warren wrote: >>> On 11/11/2012 05:22 AM, Linus Walleij wrote: >> >>>> Another solution that was discussed was whether to move >>>> the default pinctrl handle and state grab to the device >>>> core as an optional field in struct device itself, but >>>> I'd like to first propose this less intrusive mechanism. >> >>> I think doing that approach makes a lot more sense; wouldn't it >>> completely avoid the issues with deferred probe that this notifier-based >>> method can't solve? It would also be very much in line with e.g. >>> dev_get_regmap() - if every resource that a driver required were handled >>> like that, then deferred probe could be significantly isolated into the >>> driver core rather than in every driver... >> >> I have to say that I agree with this, notifiers seem to make life more >> complicated for limited gain. Otherwise I guess we could enhance >> notifiers so that they're able to trigger deferrals? > > OK I'll have to come up with a patch to the device core > instead... it'll be much simpler anyway and if both of you guys > can back it I guess Greg might be OK with it too.
I did have one thought here; how will this interact with hogs? If a device's pinctrl configuration must be pinctrl_get()'d before the device is probed, then a pinctrl device with hogs will never get probed because it won't be registered to provide the pinctrl node parsing. Solutions might include: a) Some special case where if the pinctrl driver only can't probe due to missing pinctrl from its own node, don't defer the probe, but defer the pinctrl_get(). b) Separate out DT node parsing from device instantiation, so that the driver can always parse the DT, without needing the context of a specific pinctrl device to do so. I haven't thought through this in any detail though. -- 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/
