drivers: pwm_nrf5_sw: Use GPIOTE SET and CLR tasks when available

When possible, use separate GPIOTE tasks for setting the PWM output
high and low instead of using one task to toggle it. This is crucial
for DPPI where the same task cannot be used in more than one channel.

Signed-off-by: Andrzej Głąbek <[email protected]>

Author: anangl

drivers/pwm/pwm_nrf5_sw.c

@@ -237,9 +237,23 @@ static int pwm_nrf5_sw_set_cycles(const struct device *dev, uint32_t channel,
 
 	/* setup PPI */
 	uint32_t pulse_end_event_address, period_end_event_address;
-	uint32_t gpiote_out_task_address =
-		nrf_gpiote_task_address_get(NRF_GPIOTE,
-			nrf_gpiote_out_task_get(gpiote_ch));
+	nrf_gpiote_task_t pulse_end_task, period_end_task;
+#if defined(GPIOTE_FEATURE_SET_PRESENT) && defined(GPIOTE_FEATURE_CLR_PRESENT)
+	if (active_level == 0) {
+		pulse_end_task  = nrf_gpiote_set_task_get(gpiote_ch);
+		period_end_task = nrf_gpiote_clr_task_get(gpiote_ch);
+	} else {
+		pulse_end_task  = nrf_gpiote_clr_task_get(gpiote_ch);
+		period_end_task = nrf_gpiote_set_task_get(gpiote_ch);
+	}
+#else
+	pulse_end_task = period_end_task = nrf_gpiote_out_task_get(gpiote_ch);
+#endif
+	uint32_t pulse_end_task_address =
+		nrf_gpiote_task_address_get(NRF_GPIOTE, pulse_end_task);
+	uint32_t period_end_task_address =
+		nrf_gpiote_task_address_get(NRF_GPIOTE, period_end_task);
+
 	if (USE_RTC) {
 		uint32_t clear_task_address =
 			nrf_rtc_event_address_get(rtc, NRF_RTC_TASK_CLEAR);
@@ -273,11 +287,11 @@ static int pwm_nrf5_sw_set_cycles(const struct device *dev, uint32_t channel,
 	nrf_ppi_channel_endpoint_setup(NRF_PPI,
 				       ppi_chs[0],
 				       pulse_end_event_address,
-				       gpiote_out_task_address);
+				       pulse_end_task_address);
 	nrf_ppi_channel_endpoint_setup(NRF_PPI,
 				       ppi_chs[1],
 				       period_end_event_address,
-				       gpiote_out_task_address);
+				       period_end_task_address);
 	nrf_ppi_channels_enable(NRF_PPI, ppi_mask);
 
 	/* start timer, hence PWM */