label string for kirkwood gpiochip

label string for kirkwood gpiochip

[Holger Brunck]

Hi,
we recently switched with our kirkwood based board to a newer kernel version.
Our application code is written in that way if someone request an gpio in
userspace that he do search the gpiochip via the gpio label.

The newer kernel version handles the gpiochip on kirkwood in a different way.
The orion_gpio_init function in arch/arm/mach-kirkwood/irq.c was called twice.
Once for first 32 gpios and a second time for the remaining 18 gpios. This
causes that the gpio framework shows two gpiochips in the sysfs with the same
label (orion_gpio).

[@km_kirkwood /]# cat /sys/class/gpio/gpiochip0/label
orion_gpio
[@km_kirkwood /]# cat /sys/class/gpio/gpiochip32/label
orion_gpio

So my question is simply, shouldn't be the string for a gpiochip unique in the
system and therefore this should be fixed or was this intended?

Best regards
Holger Brunck

label string for kirkwood gpiochip

[Nicolas Pitre]

On Thu, 15 Dec 2011, Holger Brunck wrote:

> Hi,
> we recently switched with our kirkwood based board to a newer kernel version.
> Our application code is written in that way if someone request an gpio in
> userspace that he do search the gpiochip via the gpio label.
> 
> The newer kernel version handles the gpiochip on kirkwood in a different way.
> The orion_gpio_init function in arch/arm/mach-kirkwood/irq.c was called twice.
> Once for first 32 gpios and a second time for the remaining 18 gpios. This
> causes that the gpio framework shows two gpiochips in the sysfs with the same
> label (orion_gpio).
> 
> [@km_kirkwood /]# cat /sys/class/gpio/gpiochip0/label
> orion_gpio
> [@km_kirkwood /]# cat /sys/class/gpio/gpiochip32/label
> orion_gpio
> 
> So my question is simply, shouldn't be the string for a gpiochip unique in the
> system and therefore this should be fixed or was this intended?

I don't think that was intended.


Nicolas

label string for kirkwood gpiochip

[Holger Brunck]

On 12/15/2011 03:22 PM, Nicolas Pitre wrote:
>>
>> The newer kernel version handles the gpiochip on kirkwood in a different way.
>> The orion_gpio_init function in arch/arm/mach-kirkwood/irq.c was called twice.
>> Once for first 32 gpios and a second time for the remaining 18 gpios. This
>> causes that the gpio framework shows two gpiochips in the sysfs with the same
>> label (orion_gpio).
>>
>> [@km_kirkwood /]# cat /sys/class/gpio/gpiochip0/label
>> orion_gpio
>> [@km_kirkwood /]# cat /sys/class/gpio/gpiochip32/label
>> orion_gpio
>>
>> So my question is simply, shouldn't be the string for a gpiochip unique in the
>> system and therefore this should be fixed or was this intended?
> 
> I don't think that was intended.
> 

Ok, how should this be done? We could add an additional  param chip_label to

void __init orion_gpio_init(int gpio_base, int ngpio,
                            u32 base, int mask_offset, int secondary_irq_base);

and fix the callers accordingly or we could add a simple static counter in
orion_gpio_init and add a suffix _0, _1, _2 to the label to make it unique
without touching the clients...

Best regards
Holger

label string for kirkwood gpiochip

[Nicolas Pitre]

On Thu, 15 Dec 2011, Holger Brunck wrote:

> On 12/15/2011 03:22 PM, Nicolas Pitre wrote:
> >>
> >> The newer kernel version handles the gpiochip on kirkwood in a different way.
> >> The orion_gpio_init function in arch/arm/mach-kirkwood/irq.c was called twice.
> >> Once for first 32 gpios and a second time for the remaining 18 gpios. This
> >> causes that the gpio framework shows two gpiochips in the sysfs with the same
> >> label (orion_gpio).
> >>
> >> [@km_kirkwood /]# cat /sys/class/gpio/gpiochip0/label
> >> orion_gpio
> >> [@km_kirkwood /]# cat /sys/class/gpio/gpiochip32/label
> >> orion_gpio
> >>
> >> So my question is simply, shouldn't be the string for a gpiochip unique in the
> >> system and therefore this should be fixed or was this intended?
> > 
> > I don't think that was intended.
> > 
> 
> Ok, how should this be done? We could add an additional  param chip_label to
> 
> void __init orion_gpio_init(int gpio_base, int ngpio,
>                             u32 base, int mask_offset, int secondary_irq_base);
> 
> and fix the callers accordingly or we could add a simple static counter in
> orion_gpio_init and add a suffix _0, _1, _2 to the label to make it unique
> without touching the clients...

The later would be less intrusive at this point.

Eventually this should be hooked into the pinctrl subsystem.


Nicolas