mimxrt/machine_adc: Support ADC channel groups on rt117x.

The rt117x uses the LPADC peripheral which supports both A-side and B-side
channel inputs, e.g. ADC1_CH1A and ADC1_CH1B.

Previously, only `kLPADC_SampleChannelSingleEndSideA` was being used during
capture, while the pin may be in side B.  The fix in this commit detects
the side based on the pin configuration and sets `sampleChannelMode`
appropriately.

Signed-off-by: Alon Bar-Lev <alon.barlev@gmail.com>

ports/mimxrt/boards/make-pins.py

@@ -61,18 +61,23 @@ class MimxrtPin(boardgen.Pin):
 
         elif af_name == "ADC":
             adc_regex = r"ADC(?P<instance>\d*)_IN(?P<channel>\d*)"
-            lpadc_regex = r"ADC(?P<instance>\d*)_CH(?P<channel>\d*)"  # LPADC for MIMXRT11xx chips
+            lpadc_regex = r"ADC(?P<instance>\d*)_CH(?P<channel>\d*)(?P<channel_group>.*)"  # LPADC for MIMXRT11xx chips
 
             matches = re.finditer(adc_regex, af, re.MULTILINE)
             for match in matches:
                 self._adc_fns.append(
-                    (int(match.group("instance")), int(match.group("channel")), "ADC")
+                    (int(match.group("instance")), int(match.group("channel")), 0, "ADC")
                 )
 
             matches = re.finditer(lpadc_regex, af, re.MULTILINE)
             for match in matches:
                 self._adc_fns.append(
-                    (int(match.group("instance")), int(match.group("channel")), "LPADC")
+                    (
+                        int(match.group("instance")),
+                        int(match.group("channel")),
+                        ord(match.group("channel_group")[0]) - ord("A"),
+                        "LPADC",
+                    )
                 )
 
     # Use the PIN() macro defined in samd_prefix.c for defining the pin
@@ -122,9 +127,11 @@ class MimxrtPin(boardgen.Pin):
                 "static const machine_pin_adc_obj_t pin_{:s}_adc[] = {{".format(self.name()),
                 file=out_source,
             )
-            for instance, channel, peripheral in self._adc_fns:
+            for instance, channel, channel_group, peripheral in self._adc_fns:
                 print(
-                    "    PIN_ADC({:s}{:d}, {:d}),".format(peripheral, instance, channel),
+                    "    PIN_ADC({:s}{:d}, {:d}, {:d}),".format(
+                        peripheral, instance, channel, channel_group
+                    ),
                     file=out_source,
                 )
             print("};", file=out_source)

ports/mimxrt/boards/mimxrt_prefix.c

@@ -16,10 +16,11 @@
         .pad_config = (uint32_t)(_pad_config), \
     } \
 
-#define PIN_ADC(_instance, _channel) \
+#define PIN_ADC(_instance, _channel, _channel_group) \
     { \
         .instance = (_instance), \
-        .channel = (_channel) \
+        .channel = (_channel), \
+        .channel_group = (_channel_group), \
     } \
 
 #define PIN(_name, _gpio, _pin, _af_list, _adc_list_len, _adc_list) \

ports/mimxrt/machine_adc.c

@@ -64,7 +64,19 @@ static void mp_machine_adc_print(const mp_print_t *print, mp_obj_t self_in, mp_p
     // Get ADC adc id
     for (int i = 1; i < sizeof(adc_bases) / sizeof(ADC_Type *); ++i) {
         if (adc_bases[i] == self->adc) {
-            mp_printf(print, "ADC(%u, channel=%u)", i, self->channel);
+            mp_printf(
+                print,
+                "ADC(%u, channel=%u"
+                #if defined(MIMXRT117x_SERIES)
+                ", channel_input=%u"
+                #endif
+                ")",
+                i,
+                self->channel
+                #if defined(MIMXRT117x_SERIES)
+                , self->channel_group
+                #endif
+                );
             break;
         }
     }
@@ -83,12 +95,13 @@ static mp_obj_t mp_machine_adc_make_new(const mp_obj_type_t *type, size_t n_args
     // Extract arguments
     ADC_Type *adc_instance = pin->adc_list[0].instance;  // NOTE: we only use the first ADC assignment - multiple assignments are not supported for now
     uint8_t channel = pin->adc_list[0].channel;
+    uint8_t channel_group = pin->adc_list[0].channel_group;
 
     // Create ADC Instance
     machine_adc_obj_t *o = mp_obj_malloc(machine_adc_obj_t, &machine_adc_type);
     o->adc = adc_instance;
     o->channel = (uint8_t)channel;
-    o->channel_group = 0;
+    o->channel_group = channel_group;
     o->resolution = 4096;  // NOTE: currently only 12bit resolution supported
 
     return MP_OBJ_FROM_PTR(o);
@@ -104,6 +117,11 @@ static mp_int_t mp_machine_adc_read_u16(machine_adc_obj_t *self) {
     LPADC_GetDefaultConvCommandConfig(&adc_config);
     adc_config.channelNumber = self->channel;
     adc_config.sampleScaleMode = kLPADC_SamplePartScale;
+    if (self->channel_group == 0) {
+        adc_config.sampleChannelMode = kLPADC_SampleChannelSingleEndSideA;
+    } else {
+        adc_config.sampleChannelMode = kLPADC_SampleChannelSingleEndSideB;
+    }
     LPADC_SetConvCommandConfig(self->adc, 1, &adc_config);
 
     // Set Trigger mode

ports/mimxrt/pin.h

@@ -117,6 +117,7 @@ typedef struct {
 typedef struct {
     ADC_Type *instance;
     uint8_t channel;
+    uint8_t channel_group;
 } machine_pin_adc_obj_t;
 
 typedef struct {