Argument to PAL UART callbacks Topic is solved

[josesimoes]

Unlike several other callbacks the UART are missing an argument. Having that is VERY VERY handy for a bunch of use cases.
I couldn't find any thread requesting this, but I would be surprised if I was the first suggesting this.

Please consider this suggestion for a future improvement or link to an already existing suggestion!

[RoccoMarco]

HI,
Moved in a more proper section.

Anyway we are talking of PAL or UART? Can you explain with a code example what you are talking about?

[josesimoes]

Hi,

Thanks for the prompt reply!

Here's an example of a callback that has args: palSetLineCallback
You have the line, the callback AND an argument that you can pass whatever is convinient for your code AT the event handler.

On the other hand UARTConfig has several callbacks for Tx, Rx, etc (uartcb_t) but that declaration only accepts the UARTDriver as argument. If it could accept a void arg as the above, it would be awesome because one could use that in the event handler (if needed, of course).

As we are at it, this is valid for any other driver callback that does not support args, btw.


Hope I've explained myself a little better now!

[apmorton]

I haven't looked at all drivers, but it seems like a pretty common pattern in ChibiOS HAL.

At least for the UART driver it exists.

https://github.com/ChibiOS/ChibiOS/blob ... lld.h#L550

If you add the following to your halconf you can include any additional fields in the UARTDriver structure that you need.

Code: Select all

#define UART_DRIVER_EXT_FIELDS \
void *mycontext; \
int myotherthing;


Since the callbacks get a pointer to the UARTDriver structure you can access them like so:

Code: Select all

void txend1_cb(UARTDriver *uartp) {
   MyContextType *ctx = (MyContextType*)uartp->mycontext;
   
   doSomething(ctx, ...);
}


[josesimoes]

That looks promising. Thanks for the tip!

My suggestion with arguments was to make it kind of in line with other drivers callbacks.
It should do its purpose with any of those alternatives.

[Giovanni]

Hi,

HAL callbacks do not have parameters, this is true for all driver except PAL (see below), this is not necessary because you can extend the driver structure as suggested by apmorton.

The PAL driver has arguments because it is a special case, it does not have an object that can be extended.

Giovanni