On 19/12/2019 09:15:02+0000, Eugen.Hristev@xxxxxxxxxxxxx wrote: > > > On 18.12.2019 18:58, Alexandre Belloni wrote: > > On 18/12/2019 16:52:21+0000, Eugen.Hristev@xxxxxxxxxxxxx wrote: > >> > >> > >> On 18.12.2019 18:43, Alexandre Belloni wrote: > >> > >>> Hi, > >>> > >>> On 18/12/2019 16:24:00+0000, Eugen.Hristev@xxxxxxxxxxxxx wrote: > >>>> From: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx> > >>>> > >>>> This allows the RTC node to have child nodes in DT. > >>>> This allows subnodes to be probed. > >>>> > >>>> Signed-off-by: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx> > >>>> --- > >>>> drivers/rtc/rtc-at91rm9200.c | 2 +- > >>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>> > >>>> diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c > >>>> index 3b833e0..f1b5b3d 100644 > >>>> --- a/drivers/rtc/rtc-at91rm9200.c > >>>> +++ b/drivers/rtc/rtc-at91rm9200.c > >>>> @@ -421,7 +421,7 @@ static int __init at91_rtc_probe(struct platform_device *pdev) > >>>> at91_rtc_write_ier(AT91_RTC_SECEV); > >>>> > >>>> dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n"); > >>>> - return 0; > >>>> + return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev); > >>>> > >>> > >>> You can avoid the DT binding change and DT parsing by using > >>> platform_add_device here. I don't think there is any point describing > >>> the trigger as a child node (a watchdog functionality wouldn't be > >>> described for example). > >>> > >> > >> Hi, > >> > >> It's needed because the ADC needs a link to the trigger device. This is > >> a hardware link inside the SoC, so I thought the best way is to describe > >> this hardware is in the Device Tree. > >> Otherwise the ADC node is unaware of the RTC triggering possibility. > >> If we just assign the RTC trigger device to the ADC through the sysfs, > >> the ADC cannot distinguish between the RTC trigger and other various > >> triggers which can be attached. > >> > > > > I'm not sure this links is required but I will let Jonathan review. Even > > if it is needed, you can still use the rtc node to describe that link. > > Actually, the RTC node could potentially have two different ADC > triggers. There is another OUT1 field that can do a second trigger for > the ADC only for the last channel. Future development might add this > trigger, so, with that in mind, I think it's best to link the exact > trigger and not the RTC node. Nothing prevents you from using an index with the phandle (and I would add a type in that case then). Having subnodes in the DT is not really a good idea. The IP is the RTC, it just happens to have some outputs. See what has been done for the PMC. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
