[nrf fromtree] 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]>
(cherry picked from commit ece7da5)

Author: nika-nordic

drivers/adc/adc_nrfx_saadc.c

@@ -32,7 +32,7 @@ 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),
@@ -41,6 +41,9 @@ 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
 
@@ -274,13 +277,8 @@ 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;
 	}
@@ -295,17 +293,18 @@ 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,
@@ -532,7 +531,12 @@ 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(