On Wed, 30 May 2018 22:39:03 +0200 Janusz Krzysztofik <jmkrzy...@gmail.com> wrote:
> On Wednesday, May 30, 2018 7:52:20 PM CEST Boris Brezillon wrote: > > On Wed, 30 May 2018 19:43:09 +0200 > > > > Janusz Krzysztofik <jmkrzy...@gmail.com> wrote: > > > On Wednesday, May 30, 2018 11:05:00 AM CEST Boris Brezillon wrote: > > > > Hi Janusz, > > > > > > Hi Boris, > > > > > > > On Sat, 26 May 2018 00:20:45 +0200 > > > > > > > > Janusz Krzysztofik <jmkrzy...@gmail.com> wrote: > > > > > ... > > > > > Changes since v1: > > > > > - fix handling of devm_gpiod_get_optional() return values - thanks to > > > > > > > > > > Andy Shevchenko. > > > > > > > > Can you put the changelog after the "---" separator so that it does not > > > > appear in the final commit message? > > > > > > Yes, sure, sorry for that. > > > > > > > > +err_gpiod: > > > > > + if (err == -ENODEV || err == -ENOENT) > > > > > + err = -EPROBE_DEFER; > > > > > > > > Hm, isn't it better to make gpiod_find() return ERR_PTR(-EPROBE_DEFER) > > > > here [1]? At least, ENOENT should not be turned into EPROBE_DEFER, > > > > because it's returned when there's no entry matching the requested gpio > > > > in the lookup table, and deferring the probe won't solve this problem. > > > > > > ENOENT is also returned when no matching lookup table is found. That may > > > happen if consumer dev_name stored in the table differs from dev_name > > > assigned to the consumer by its bus, the platform bus in this case. For > > > that reason I think the consumer dev_name should be initialized in the > > > table after the device is registered, when its actual dev_name can be > > > obtained. If that device registration happens after the driver is already > > > registered, e.g., at late_initcall, the device is probed before its > > > lookup table is ready. For that reason returning EPROBE_DEFER seems > > > better to me even in the ENOENT case. > > Sorry, I don't get it. Aren't GPIO lookup tables supposed to be declared > > in board files, especially if the GPIO is used by a platform device? > > When would you have a lookup table registered later in the init/boot > > process? > > When e.g. I'd like to register my GPIO consumer platform device at > late_initcall for some reason, and I'm not sure what exact dev_name my > consomer will be registered with by the platform bus. You should know the name before the device is registered. > In that case I think I > should assign dev_name to the lookup table after the consumer device is > registered and its exact dev_name can be obtained, then register the table, I'm pretty sure it's not supposed to work like that. Resources attached to a device should be defined before the device is registered, not after, simply because when you call platform_device_register(), the device might be directly bind to the driver before the platform_device_register() calls return, and the driver will fail to probe the device if it doesn't find the GPIO it needs.