Re: [PATCH v3 03/16] mfd: mfd-core: match device tree node against reg property

Michael Walle
2020-06-08T15:21:35Z

Am 2020-06-08 16:24, schrieb Lee Jones:
> On Mon, 25 May 2020, Michael Walle wrote:
>> Am 2020-05-15 12:28, schrieb Lee Jones:
>> > On Thu, 30 Apr 2020, Michael Walle wrote:
>> >
>> > > Hi Lee,
>> > >
>> > > Am 2020-04-23 19:45, schrieb Michael Walle:
>> > > > There might be multiple children with the device tree compatible, for
>> > > > example if a MFD has multiple instances of the same function. In this
>> > > > case only the first is matched and the other children get a wrong
>> > > > of_node reference.
>> > > > Add a new option to match also against the unit address of the child
>> > > > node. Additonally, a new helper OF_MFD_CELL_REG is added.
>
> [...]
>
>> > > > diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
>> > > > index d01d1299e49d..c2c0ad6b14f3 100644
>> > > > --- a/include/linux/mfd/core.h
>> > > > +++ b/include/linux/mfd/core.h
>> > > > @@ -13,8 +13,11 @@
>> > > > #include <linux/platform_device.h>
>> > > >
>> > > > #define MFD_RES_SIZE(arr) (sizeof(arr) / sizeof(struct resource))
>> > > > +#define MFD_OF_REG_VALID BIT(31)
>> >
>> > What about 64bit platforms?
>>
>> The idea was to have this as a logical number. I.e. for now you may
>> only
>> have one subdevice per unique compatible string. In fact, if you have
>> a
>> look at the ab8500.c, there are multiple "stericsson,ab8500-pwm"
>> subdevices. But there is only one DT node for all three of it. I guess
>> this works as long as you don't use phandles to reference the pwm node
>> in the device tree. Or you don't want to use device tree properties
>> per subdevice (for example the "timeout-sec" of a watchdog device).
>
> This is not a good example, as the "stericsson,ab8500-pwm" is
> legitimate. Here we are registering 3 potential devices, but only
> instantiating 1 of them.

Mh?

static const struct mfd_cell ab8500_devs[] = {
..
OF_MFD_CELL("ab8500-pwm",
NULL, NULL, 0, 1, "stericsson,ab8500-pwm"),
OF_MFD_CELL("ab8500-pwm",
NULL, NULL, 0, 2, "stericsson,ab8500-pwm"),
OF_MFD_CELL("ab8500-pwm",
NULL, NULL, 0, 3, "stericsson,ab8500-pwm"),
..
}

And in pwm-ab8500.c there are three offsets based on the pdev->id.

Am I missing something here?

--
-michael