drivers: counter: esp32: add guard period support

Implements guard period support.

Signed-off-by: Sylvio Alves <[email protected]>

Author: sylvioalves

drivers/counter/counter_esp32_tmr.c

@@ -29,6 +29,7 @@ struct counter_esp32_top_data {
 	uint32_t ticks;
 	void *user_data;
 	bool auto_reload;
+	uint32_t guard_period;
 };
 
 struct counter_esp32_config {
@@ -144,33 +145,60 @@ static int counter_esp32_set_alarm(const struct device *dev, uint8_t chan_id,
 {
 	ARG_UNUSED(chan_id);
 	struct counter_esp32_data *data = dev->data;
+	bool absolute = alarm_cfg->flags & COUNTER_ALARM_CFG_ABSOLUTE;
 	uint32_t ticks = alarm_cfg->ticks;
+	uint32_t top = data->top_data.ticks;
+	uint32_t max_rel_val = data->top_data.ticks;
 	uint32_t now;
+	uint32_t diff;
+	int err = 0;
+	bool irq_on_late = 0;
 
 	if (ticks > data->top_data.ticks) {
 		return -EINVAL;
 	}
 
+	data->alarm_cfg.callback = alarm_cfg->callback;
+	data->alarm_cfg.user_data = alarm_cfg->user_data;
+
 	counter_esp32_get_value(dev, &now);
 
-	if ((alarm_cfg->flags & COUNTER_ALARM_CFG_ABSOLUTE) == 0) {
+	if (absolute == 0) {
 		ticks += now;
 		if (ticks > data->top_data.ticks) {
 			ticks -= (data->top_data.ticks + 1);
 		}
 		timer_ll_set_alarm_value(data->hal_ctx.dev, data->hal_ctx.timer_id,
 					 (now + alarm_cfg->ticks));
 	} else {
+		irq_on_late = alarm_cfg->flags & COUNTER_ALARM_CFG_EXPIRE_WHEN_LATE;
+		max_rel_val = top - data->top_data.guard_period;
 		timer_ll_set_alarm_value(data->hal_ctx.dev, data->hal_ctx.timer_id,
 					 alarm_cfg->ticks);
 	}
 
-	timer_ll_enable_intr(data->hal_ctx.dev, TIMER_LL_EVENT_ALARM(data->hal_ctx.timer_id), true);
-	timer_ll_enable_alarm(data->hal_ctx.dev, data->hal_ctx.timer_id, TIMER_ALARM_EN);
-	data->alarm_cfg.callback = alarm_cfg->callback;
-	data->alarm_cfg.user_data = alarm_cfg->user_data;
+	diff = (alarm_cfg->ticks - now);
+	if (diff > max_rel_val) {
+		if (absolute) {
+			err = -ETIME;
+		}
+		if (irq_on_late) {
+			timer_ll_enable_intr(data->hal_ctx.dev,
+					     TIMER_LL_EVENT_ALARM(data->hal_ctx.timer_id), true);
+			timer_ll_enable_alarm(data->hal_ctx.dev, data->hal_ctx.timer_id,
+					      TIMER_ALARM_EN);
+			timer_ll_set_alarm_value(data->hal_ctx.dev, data->hal_ctx.timer_id, 0);
 
-	return 0;
+		} else {
+			data->alarm_cfg.callback = NULL;
+		}
+	} else {
+		timer_ll_enable_intr(data->hal_ctx.dev,
+				     TIMER_LL_EVENT_ALARM(data->hal_ctx.timer_id), true);
+		timer_ll_enable_alarm(data->hal_ctx.dev, data->hal_ctx.timer_id, TIMER_ALARM_EN);
+	}
+
+	return err;
 }
 
 static int counter_esp32_cancel_alarm(const struct device *dev, uint8_t chan_id)
@@ -263,6 +291,29 @@ static int counter_esp32_reset(const struct device *dev)
 	return 0;
 }
 
+static uint32_t counter_esp32_get_guard_period(const struct device *dev, uint32_t flags)
+{
+	struct counter_esp32_data *data = dev->data;
+
+	ARG_UNUSED(flags);
+
+	return data->top_data.guard_period;
+}
+
+static int counter_esp32_set_guard_period(const struct device *dev, uint32_t ticks, uint32_t flags)
+{
+	struct counter_esp32_data *data = dev->data;
+
+	ARG_UNUSED(flags);
+
+	if (ticks > data->top_data.ticks) {
+		return -EINVAL;
+	}
+
+	data->top_data.guard_period = ticks;
+	return 0;
+}
+
 static DEVICE_API(counter, counter_api) = {
 	.start = counter_esp32_start,
 	.stop = counter_esp32_stop,
@@ -275,6 +326,8 @@ static DEVICE_API(counter, counter_api) = {
 	.get_pending_int = counter_esp32_get_pending_int,
 	.get_top_value = counter_esp32_get_top_value,
 	.get_freq = counter_esp32_get_freq,
+	.get_guard_period = counter_esp32_get_guard_period,
+	.set_guard_period = counter_esp32_set_guard_period,
 };
 
 static void counter_esp32_isr(void *arg)