drivers: adc: nrf: add support for nrf54l internal SAADC inputs

SAADC peripheral for nRF54L Series allows to choose internal
voltages as positive inputs.

Signed-off-by: Nikodem Kastelik <[email protected]>

drivers/adc/adc_nrfx_saadc.c

@@ -7,7 +7,8 @@
 #define ADC_CONTEXT_USES_KERNEL_TIMER
 #include "adc_context.h"
 #include <haly/nrfy_saadc.h>
-#include <zephyr/dt-bindings/adc/nrf-adc.h>
+#include <zephyr/dt-bindings/adc/nrf-saadc-nrf5x_v3.h>
+#include <zephyr/dt-bindings/adc/nrf-saadc-nrf54lx.h>
 #include <zephyr/linker/devicetree_regions.h>
 
 #define LOG_LEVEL CONFIG_ADC_LOG_LEVEL
@@ -17,6 +18,8 @@ LOG_MODULE_REGISTER(adc_nrfx_saadc);
 
 #define DT_DRV_COMPAT nordic_nrf_saadc
 
+#define SAADC_INPUT_INVALID 0xFEU
+
 #if (NRF_SAADC_HAS_AIN_AS_PIN)
 
 #if defined(CONFIG_SOC_NRF54H20) || defined(CONFIG_SOC_NRF9280)
@@ -31,7 +34,7 @@ static const uint8_t saadc_psels[NRF_SAADC_AIN7 + 1] = {
 	[NRF_SAADC_AIN7] = NRF_PIN_PORT_TO_PIN_NUMBER(7U, 1),
 };
 #elif defined(CONFIG_SOC_NRF54L15)
-static const uint8_t saadc_psels[NRF_SAADC_AIN7 + 1] = {
+static const uint32_t saadc_psels[NRF_SAADC_DVDD + 1] = {
 	[NRF_SAADC_AIN0] = NRF_PIN_PORT_TO_PIN_NUMBER(4U, 1),
 	[NRF_SAADC_AIN1] = NRF_PIN_PORT_TO_PIN_NUMBER(5U, 1),
 	[NRF_SAADC_AIN2] = NRF_PIN_PORT_TO_PIN_NUMBER(6U, 1),
@@ -40,6 +43,9 @@ static const uint8_t saadc_psels[NRF_SAADC_AIN7 + 1] = {
 	[NRF_SAADC_AIN5] = NRF_PIN_PORT_TO_PIN_NUMBER(12U, 1),
 	[NRF_SAADC_AIN6] = NRF_PIN_PORT_TO_PIN_NUMBER(13U, 1),
 	[NRF_SAADC_AIN7] = NRF_PIN_PORT_TO_PIN_NUMBER(14U, 1),
+	[NRF_SAADC_VDD]  = NRF_SAADC_INPUT_VDD,
+	[NRF_SAADC_AVDD] = NRF_SAADC_INPUT_AVDD,
+	[NRF_SAADC_DVDD] = NRF_SAADC_INPUT_DVDD,
 };
 #endif
 
@@ -273,13 +279,8 @@ static int adc_nrfx_channel_setup(const struct device *dev,
 		m_data.single_ended_channels |= BIT(channel_cfg->channel_id);
 	}
 
-	/* Keep the channel disabled in hardware (set positive input to
-	 * NRF_SAADC_INPUT_DISABLED) until it is selected to be included
-	 * in a sampling sequence.
-	 */
-
 #if (NRF_SAADC_HAS_AIN_AS_PIN)
-	if ((channel_cfg->input_positive > NRF_SAADC_AIN7) ||
+	if ((channel_cfg->input_positive >= ARRAY_SIZE(saadc_psels)) ||
 	    (channel_cfg->input_positive < NRF_SAADC_AIN0)) {
 		return -EINVAL;
 	}
@@ -294,17 +295,18 @@ static int adc_nrfx_channel_setup(const struct device *dev,
 	} else {
 		input_negative = NRF_SAADC_INPUT_DISABLED;
 	}
-
+#endif
 	/* Store the positive input selection in a dedicated array,
 	 * to get it later when the channel is selected for a sampling
 	 * and to mark the channel as configured (ready to be selected).
 	 */
-	m_data.positive_inputs[channel_id] = saadc_psels[channel_cfg->input_positive];
-#else
 	m_data.positive_inputs[channel_id] = channel_cfg->input_positive;
-#endif
 
 	nrf_saadc_channel_init(NRF_SAADC, channel_id, &config);
+	/* Keep the channel disabled in hardware (set positive input to
+	 * NRF_SAADC_INPUT_DISABLED) until it is selected to be included
+	 * in a sampling sequence.
+	 */
 	nrf_saadc_channel_input_set(NRF_SAADC,
 				    channel_id,
 				    NRF_SAADC_INPUT_DISABLED,
@@ -494,7 +496,7 @@ static int start_read(const struct device *dev,
 			/* Signal an error if a selected channel has not been
 			 * configured yet.
 			 */
-			if (m_data.positive_inputs[channel_id] == 0U) {
+			if (m_data.positive_inputs[channel_id] == SAADC_INPUT_INVALID) {
 				LOG_ERR("Channel %u not configured",
 					    channel_id);
 				return -EINVAL;
@@ -531,7 +533,12 @@ static int start_read(const struct device *dev,
 			nrf_saadc_channel_pos_input_set(
 				NRF_SAADC,
 				channel_id,
-				m_data.positive_inputs[channel_id]);
+#if NRF_SAADC_HAS_AIN_AS_PIN
+				saadc_psels[m_data.positive_inputs[channel_id]]
+#else
+				m_data.positive_inputs[channel_id]
+#endif
+				);
 			++active_channels;
 		} else {
 			nrf_saadc_burst_set(
@@ -642,6 +649,9 @@ static void saadc_irq_handler(const struct device *dev)
 
 static int init_saadc(const struct device *dev)
 {
+	for (uint8_t ch = 0; ch < ARRAY_SIZE(m_data.positive_inputs); ch++) {
+		m_data.positive_inputs[ch] = SAADC_INPUT_INVALID;
+	}
 	nrf_saadc_event_clear(NRF_SAADC, NRF_SAADC_EVENT_END);
 	nrf_saadc_event_clear(NRF_SAADC, NRF_SAADC_EVENT_CALIBRATEDONE);
 	nrf_saadc_int_enable(NRF_SAADC,