Commit ae3392c0 authored by Dharma Balasubiramani's avatar Dharma Balasubiramani Committed by William Breathitt Gray
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counter: microchip-tcb-capture: Add watch validation support 



The Timer Counter Block (TCB) exposes several kinds of events to the
Counter framework, but not every event is meaningful on every hardware
channel. Add a `watch_validate()` callback so userspace may register only
the combinations actually supported:

* Channel 0 (COUNTER_MCHP_EVCHN_CV, COUNTER_MCHP_EVCHN_RA)
   - COUNTER_EVENT_CAPTURE
   - COUNTER_EVENT_CHANGE_OF_STATE
   - COUNTER_EVENT_OVERFLOW

* Channel 1 (COUNTER_MCHP_EVCHN_RB)
   - COUNTER_EVENT_CAPTURE

* Channel 2 (COUNTER_MCHP_EVCHN_RC)
   - COUNTER_EVENT_THRESHOLD

Any other request is rejected with `-EINVAL`.

Signed-off-by: default avatarDharma Balasubiramani <dharma.b@microchip.com>
Link: https://lore.kernel.org/r/20250520-counter-tcb-v3-1-4631e2aff7ed@microchip.com


Signed-off-by: default avatarWilliam Breathitt Gray <wbg@kernel.org>
parent ace2cd11

drivers/counter/microchip-tcb-capture.c

+24 −1
Original line number Diff line number Diff line
@@ -337,6 +337,28 @@ static struct counter_comp mchp_tc_count_ext[] = { 
	COUNTER_COMP_COMPARE(mchp_tc_count_compare_read, mchp_tc_count_compare_write),

};



static int mchp_tc_watch_validate(struct counter_device *counter,

				  const struct counter_watch *watch)

{

	if (watch->channel == COUNTER_MCHP_EVCHN_CV || watch->channel == COUNTER_MCHP_EVCHN_RA)

		switch (watch->event) {

		case COUNTER_EVENT_CHANGE_OF_STATE:

		case COUNTER_EVENT_OVERFLOW:

		case COUNTER_EVENT_CAPTURE:

			return 0;

		default:

			return -EINVAL;

		}



	if (watch->channel == COUNTER_MCHP_EVCHN_RB && watch->event == COUNTER_EVENT_CAPTURE)

		return 0;



	if (watch->channel == COUNTER_MCHP_EVCHN_RC && watch->event == COUNTER_EVENT_THRESHOLD)

		return 0;



	return -EINVAL;

}



static struct counter_count mchp_tc_counts[] = {

	{

		.id = 0,
@@ -356,7 +378,8 @@ static const struct counter_ops mchp_tc_ops = { 
	.function_read  = mchp_tc_count_function_read,

	.function_write = mchp_tc_count_function_write,

	.action_read    = mchp_tc_count_action_read,

	.action_write   = mchp_tc_count_action_write

	.action_write   = mchp_tc_count_action_write,

	.watch_validate = mchp_tc_watch_validate,

};



static const struct atmel_tcb_config tcb_rm9200_config = {