diff mbox series

[04/10] rtc: at91rm9200: use of_platform_populate as return value

Message ID 1576686157-11939-5-git-send-email-eugen.hristev@microchip.com (mailing list archive)
State New, archived
Headers show
Series Enhancements to at91-sama5d2_adc and rtc trigger | expand

Commit Message

Eugen Hristev Dec. 18, 2019, 4:24 p.m. UTC 
From: Eugen Hristev <eugen.hristev@microchip.com>

This allows the RTC node to have child nodes in DT.
This allows subnodes to be probed.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
---
 drivers/rtc/rtc-at91rm9200.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Alexandre Belloni Dec. 18, 2019, 4:43 p.m. UTC | #1 
Hi,

On 18/12/2019 16:24:00+0000, Eugen.Hristev@microchip.com wrote:
> From: Eugen Hristev <eugen.hristev@microchip.com>
> 
> This allows the RTC node to have child nodes in DT.
> This allows subnodes to be probed.
> 
> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
> ---
>  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).
Eugen Hristev Dec. 18, 2019, 4:52 p.m. UTC | #2 
On 18.12.2019 18:43, Alexandre Belloni wrote:

> Hi,
> 
> On 18/12/2019 16:24:00+0000, Eugen.Hristev@microchip.com wrote:
>> From: Eugen Hristev <eugen.hristev@microchip.com>
>>
>> This allows the RTC node to have child nodes in DT.
>> This allows subnodes to be probed.
>>
>> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
>> ---
>>   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.

> --
> Alexandre Belloni, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
>
Alexandre Belloni Dec. 18, 2019, 4:58 p.m. UTC | #3 
On 18/12/2019 16:52:21+0000, Eugen.Hristev@microchip.com wrote:
> 
> 
> On 18.12.2019 18:43, Alexandre Belloni wrote:
> 
> > Hi,
> > 
> > On 18/12/2019 16:24:00+0000, Eugen.Hristev@microchip.com wrote:
> >> From: Eugen Hristev <eugen.hristev@microchip.com>
> >>
> >> This allows the RTC node to have child nodes in DT.
> >> This allows subnodes to be probed.
> >>
> >> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
> >> ---
> >>   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.
Eugen Hristev Dec. 19, 2019, 9:15 a.m. UTC | #4 
On 18.12.2019 18:58, Alexandre Belloni wrote:
> On 18/12/2019 16:52:21+0000, Eugen.Hristev@microchip.com wrote:
>>
>>
>> On 18.12.2019 18:43, Alexandre Belloni wrote:
>>
>>> Hi,
>>>
>>> On 18/12/2019 16:24:00+0000, Eugen.Hristev@microchip.com wrote:
>>>> From: Eugen Hristev <eugen.hristev@microchip.com>
>>>>
>>>> This allows the RTC node to have child nodes in DT.
>>>> This allows subnodes to be probed.
>>>>
>>>> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
>>>> ---
>>>>    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.

> 
> --
> Alexandre Belloni, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
>
Alexandre Belloni Dec. 19, 2019, 10:23 a.m. UTC | #5 
On 19/12/2019 09:15:02+0000, Eugen.Hristev@microchip.com wrote:
> 
> 
> On 18.12.2019 18:58, Alexandre Belloni wrote:
> > On 18/12/2019 16:52:21+0000, Eugen.Hristev@microchip.com wrote:
> >>
> >>
> >> On 18.12.2019 18:43, Alexandre Belloni wrote:
> >>
> >>> Hi,
> >>>
> >>> On 18/12/2019 16:24:00+0000, Eugen.Hristev@microchip.com wrote:
> >>>> From: Eugen Hristev <eugen.hristev@microchip.com>
> >>>>
> >>>> This allows the RTC node to have child nodes in DT.
> >>>> This allows subnodes to be probed.
> >>>>
> >>>> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
> >>>> ---
> >>>>    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.
Jonathan Cameron Dec. 23, 2019, 11:16 a.m. UTC | #6 
On Thu, 19 Dec 2019 11:23:21 +0100
Alexandre Belloni <alexandre.belloni@bootlin.com> wrote:

> On 19/12/2019 09:15:02+0000, Eugen.Hristev@microchip.com wrote:
> > 
> > 
> > On 18.12.2019 18:58, Alexandre Belloni wrote:  
> > > On 18/12/2019 16:52:21+0000, Eugen.Hristev@microchip.com wrote:  
> > >>
> > >>
> > >> On 18.12.2019 18:43, Alexandre Belloni wrote:
> > >>  
> > >>> Hi,
> > >>>
> > >>> On 18/12/2019 16:24:00+0000, Eugen.Hristev@microchip.com wrote:  
> > >>>> From: Eugen Hristev <eugen.hristev@microchip.com>
> > >>>>
> > >>>> This allows the RTC node to have child nodes in DT.
> > >>>> This allows subnodes to be probed.
> > >>>>
> > >>>> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
> > >>>> ---
> > >>>>    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.
> 
> 

If it can be done either way, let's avoid adding to the rtc dt binding.

Jonathan
Eugen Hristev Jan. 9, 2020, 11:19 a.m. UTC | #7 
On 23.12.2019 13:16, Jonathan Cameron wrote:

> On Thu, 19 Dec 2019 11:23:21 +0100
> Alexandre Belloni <alexandre.belloni@bootlin.com> wrote:
> 
>> On 19/12/2019 09:15:02+0000, Eugen.Hristev@microchip.com wrote:
>>>
>>>
>>> On 18.12.2019 18:58, Alexandre Belloni wrote:
>>>> On 18/12/2019 16:52:21+0000, Eugen.Hristev@microchip.com wrote:
>>>>>
>>>>>
>>>>> On 18.12.2019 18:43, Alexandre Belloni wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> On 18/12/2019 16:24:00+0000, Eugen.Hristev@microchip.com wrote:
>>>>>>> From: Eugen Hristev <eugen.hristev@microchip.com>
>>>>>>>
>>>>>>> This allows the RTC node to have child nodes in DT.
>>>>>>> This allows subnodes to be probed.
>>>>>>>
>>>>>>> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
>>>>>>> ---
>>>>>>>     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 Alexandre,

I started to work on this, I am trying to add and probe the 
rtc_adc_trigger with platform_device_add.

However, some issues arise: this means that the rtc_adc_trigger will not 
be OF-compatible, so, how can I identify the driver to probe ?
Second, by adding a new platform device from the RTC driver, would mean 
that I would have to supply it's probe/remove functions, which I cannot 
have here. Those are in the rtc_adc_trigger iio driver.

In fact, the question is, which is the mechanism you suggested, to be 
able to probe the rtc_adc_trigger, from inside the rtc driver, without 
using a child node in DT, as you requested ?
The rtc_adc_trigger needs a MEM resource, and a parent, and it must 
reside inside the IIO subsystem.

Thanks,
Eugen


>>>>>>
>>>>>
>>>>> 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.
>>
>>
> 
> If it can be done either way, let's avoid adding to the rtc dt binding.
> 
> Jonathan
> 
>
Alexandre Belloni Jan. 9, 2020, 11:52 a.m. UTC | #8 
On 09/01/2020 11:19:45+0000, Eugen.Hristev@microchip.com wrote:
> I started to work on this, I am trying to add and probe the 
> rtc_adc_trigger with platform_device_add.
> 
> However, some issues arise: this means that the rtc_adc_trigger will not 
> be OF-compatible, so, how can I identify the driver to probe ?
> Second, by adding a new platform device from the RTC driver, would mean 
> that I would have to supply it's probe/remove functions, which I cannot 
> have here. Those are in the rtc_adc_trigger iio driver.
> 
> In fact, the question is, which is the mechanism you suggested, to be 
> able to probe the rtc_adc_trigger, from inside the rtc driver, without 
> using a child node in DT, as you requested ?
> The rtc_adc_trigger needs a MEM resource, and a parent, and it must 
> reside inside the IIO subsystem.
> 

As suggested earlier in the thread, you can use platform_add_device
which fits all your requirements.
diff mbox series

Patch

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);
 
 err_clk:
 	clk_disable_unprepare(sclk);