tow devices share one interrupt

[Stefan Kalkowski]

Hi,

On 05/11/2013 01:42 PM, gaober wrote:
> hi!
> i have 5 gpio keys,they are from module GPIO2,and share the same IRQ
> line MA_IRQ_30.how can i implement the gipo key driver?
> i use code below to init gpio and irq
>  void _init_gpio(int gpio)
>  {
>   // Configure GPIO
>   _gpio.direction_input(gpio);
>   _gpio.debouncing_time(gpio, 31*100);
>   _gpio.debounce_enable(gpio, 1);
>   _gpio.falling_detect(gpio, 1);
>   _gpio.irq_enable(gpio, 1);
>  }
> the "int gpio" will be 32,33,36,37,38
> when i use
> _gpio.irq_sigh(_sig_rec.manage(&_sig_ctx), gpio);
> problem shows:should i use it only once or fifth?
> if i use it only once,how can i determine which gpio trigger the irq?may
> be use function _gpio.datain(init gpio) to detect it?

If every GPIO key uses another GPIO pin, then of course you'll need to
register a signal handler respectively a "Signal_context_capability" for
every single pin, but that depends on your device whether it uses one
pin or multiple.

The "datain(int gpio)" function, just tells you what input level the
appropriate GPIO pin has (low or high).

To distinguish different signals (e.g. GPIO interrupts) hitting one and
the same signal receiver, you've to use different Signal_context objects
for each signal source. For each signal received, you get the
appropriate "Signal_context" delivered. You can use the received context
to compare it against each context you've registered beforehand to find
out which pin was triggered.

> another question:
> my touchsreen and the 5 gpio keys share the same IRQ line MA_IRQ_30.how
> can deal with the tow kinds of driver?

Well, I assume "MA_IRQ_30" denotes the interrupt line between the second
GPIO controller, and the interrupt controller of the ARM core, and not
the GPIO pin. This interrupt is delivered to the GPIO driver itself, and
shouldn't be used by your touchscreen, nor GPIO key driver. The GPIO key
driver, and touchscreen driver as clients of the GPIO driver should
register signal handlers for their corresponding GPIO pins. When an
interrupt occurs on line "MA_IRQ_30", the GPIO driver gets informed, and
after reading the appropriated device registers, decides which device
(respectively pin) connected to the GPIO controller was responsible for
the interrupt. Then it triggers a signal to inform the right client,
either the touchscreen signal handler, or one of the GPIO key handlers.

> in/os/drivers/input/,make two directoris named ft5406 and gpio_keys?when
> the irq comes?what will it be?which void handle_event() will execute?

In general, I would recommend to combine both devices into one and the
same input driver. In fact, both devices are just different sources to
the input system. Probably, you want e.g. the window manager "nitpicker"
to get both kinds of input events, so they can be distributed to
nitpicker clients. If you've two different input driver, you'll have to
rework nitpicker to take more than one input driver.

Regards
Stefan

PS: Btw. the GPIO session interface was rewritten entirely. The changes
are now laying in the staging branch of the official Genode repository,
but will migrate to master probably soon. The new interface allow for
exactly one GPIO pin per GPIO session. Moreover, the interface is
slightly more narrow:
https://github.com/genodelabs/genode/commit/ca92984bccf5e12c970e04fc2923bd19e0bdc7f9

>  
> thanks very much!
> 
> 
> 
> 
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-- 
Stefan Kalkowski
Genode Labs

http://www.genode-labs.com/ · http://genode.org/