stm32/adc: Simplify and generalise how pin_adcX table is defined.

The ADC_FIRST_GPIO_CHANNEL and ADC_LAST_GPIO_CHANNEL macros are no longer
needed.  Instead the pin_adcX table (X = 1, 2, 3) is now generated to be
the exact size needed for a given MCU, and MP_ARRAY_SIZE(pin_adcX) is used
to determine the upper bound.

This commit also allows CPU pins to be excluded from ADC configuration if
they are hidden by prefixing their name with a "-".

Signed-off-by: Damien George <damien@micropython.org>

2 files changed, 40 insertions, 55 deletions

diff --git a/ports/stm32/adc.c b/ports/stm32/adc.c
index 55dc3083b..09cd3306b 100644
--- a/ports/stm32/adc.c
+++ b/ports/stm32/adc.c
@@ -70,8 +70,6 @@
 
 #if defined(STM32F0)
 
-#define ADC_FIRST_GPIO_CHANNEL  (0)
-#define ADC_LAST_GPIO_CHANNEL   (15)
 #define ADC_SCALE_V             (3.3f)
 #define ADC_CAL_ADDRESS         (0x1ffff7ba)
 #define ADC_CAL1                ((uint16_t *)0x1ffff7b8)
@@ -80,8 +78,6 @@
 
 #elif defined(STM32F4)
 
-#define ADC_FIRST_GPIO_CHANNEL  (0)
-#define ADC_LAST_GPIO_CHANNEL   (15)
 #define ADC_SCALE_V             (3.3f)
 #define ADC_CAL_ADDRESS         (0x1fff7a2a)
 #define ADC_CAL1                ((uint16_t *)(ADC_CAL_ADDRESS + 2))
@@ -90,8 +86,6 @@
 
 #elif defined(STM32F7)
 
-#define ADC_FIRST_GPIO_CHANNEL  (0)
-#define ADC_LAST_GPIO_CHANNEL   (15)
 #define ADC_SCALE_V             (3.3f)
 #if defined(STM32F722xx) || defined(STM32F723xx) || \
     defined(STM32F732xx) || defined(STM32F733xx)
@@ -106,8 +100,6 @@
 
 #elif defined(STM32H7)
 
-#define ADC_FIRST_GPIO_CHANNEL  (0)
-#define ADC_LAST_GPIO_CHANNEL   (16)
 #define ADC_SCALE_V             (3.3f)
 #define ADC_CAL_ADDRESS         (0x1FF1E860)
 #define ADC_CAL1                ((uint16_t *)(0x1FF1E820))
@@ -116,8 +108,6 @@
 
 #elif defined(STM32L4) || defined(STM32WB)
 
-#define ADC_FIRST_GPIO_CHANNEL  (1)
-#define ADC_LAST_GPIO_CHANNEL   (16)
 #define ADC_SCALE_V             (VREFINT_CAL_VREF / 1000.0f)
 #define ADC_CAL_ADDRESS         (VREFINT_CAL_ADDR)
 #define ADC_CAL1                (TEMPSENSOR_CAL1_ADDR)
@@ -179,7 +169,7 @@
 typedef struct _pyb_obj_adc_t {
     mp_obj_base_t base;
     mp_obj_t pin_name;
-    int channel;
+    uint32_t channel;
     ADC_HandleTypeDef handle;
 } pyb_obj_adc_t;
 
@@ -308,13 +298,6 @@ STATIC void adcx_init_periph(ADC_HandleTypeDef *adch, uint32_t resolution) {
 }
 
 STATIC void adc_init_single(pyb_obj_adc_t *adc_obj) {
-
-    if (ADC_FIRST_GPIO_CHANNEL <= adc_obj->channel && adc_obj->channel <= ADC_LAST_GPIO_CHANNEL) {
-        // Channels 0-16 correspond to real pins. Configure the GPIO pin in ADC mode.
-        const pin_obj_t *pin = pin_adc_table[adc_obj->channel];
-        mp_hal_pin_config(pin, MP_HAL_PIN_MODE_ADC, MP_HAL_PIN_PULL_NONE, 0);
-    }
-
     adc_obj->handle.Instance = ADCx;
     adcx_init_periph(&adc_obj->handle, ADC_RESOLUTION_12B);
 
@@ -431,8 +414,8 @@ STATIC mp_obj_t adc_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_
     } else {
         const pin_obj_t *pin = pin_find(pin_obj);
         if ((pin->adc_num & PIN_ADC_MASK) == 0) {
-            // No ADC1 function on that pin
-            mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("pin %q does not have ADC capabilities"), pin->name);
+            // No ADC function on the given pin.
+            mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("Pin(%q) doesn't have ADC capabilities"), pin->name);
         }
         channel = pin->adc_channel;
     }
@@ -441,11 +424,11 @@ STATIC mp_obj_t adc_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_
         mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("not a valid ADC Channel: %d"), channel);
     }
 
-
-    if (ADC_FIRST_GPIO_CHANNEL <= channel && channel <= ADC_LAST_GPIO_CHANNEL) {
-        // these channels correspond to physical GPIO ports so make sure they exist
-        if (pin_adc_table[channel] == NULL) {
-            mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("channel %d not available on this board"), channel);
+    // If this channel corresponds to a pin then configure the pin in ADC mode.
+    if (channel < MP_ARRAY_SIZE(pin_adc_table)) {
+        const pin_obj_t *pin = pin_adc_table[channel];
+        if (pin != NULL) {
+            mp_hal_pin_config(pin, MP_HAL_PIN_MODE_ADC, MP_HAL_PIN_PULL_NONE, 0);
         }
     }
 
@@ -730,11 +713,10 @@ void adc_init_all(pyb_adc_all_obj_t *adc_all, uint32_t resolution, uint32_t en_m
             mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("resolution %d not supported"), resolution);
     }
 
-    for (uint32_t channel = ADC_FIRST_GPIO_CHANNEL; channel <= ADC_LAST_GPIO_CHANNEL; ++channel) {
+    for (uint32_t channel = 0; channel < MP_ARRAY_SIZE(pin_adcall_table); ++channel) {
         // only initialise those channels that are selected with the en_mask
         if (en_mask & (1 << channel)) {
-            // Channels 0-16 correspond to real pins. Configure the GPIO pin in
-            // ADC mode.
+            // If this channel corresponds to a pin then configure the pin in ADC mode.
             const pin_obj_t *pin = pin_adcall_table[channel];
             if (pin) {
                 mp_hal_pin_config(pin, MP_HAL_PIN_MODE_ADC, MP_HAL_PIN_PULL_NONE, 0);
diff --git a/ports/stm32/boards/make-pins.py b/ports/stm32/boards/make-pins.py
index a19532331..70213de6a 100755
--- a/ports/stm32/boards/make-pins.py
+++ b/ports/stm32/boards/make-pins.py
@@ -287,6 +287,7 @@ class Pins(object):
     def __init__(self):
         self.cpu_pins = []  # list of NamedPin objects
         self.board_pins = []  # list of NamedPin objects
+        self.adc_table_size = {}  # maps ADC number X to size of pin_adcX table
 
     def find_pin(self, port_num, pin_num):
         for named_pin in self.cpu_pins:
@@ -353,27 +354,27 @@ class Pins(object):
         self.print_named("board", self.board_pins)
 
     def print_adc(self, adc_num):
-        print("")
-        print("const pin_obj_t * const pin_adc{:d}[] = {{".format(adc_num))
-        for channel in range(17):
-            if channel == 16:
-                print("#if defined(STM32L4)")
-            adc_found = False
-            for named_pin in self.cpu_pins:
-                pin = named_pin.pin()
-                if (
-                    pin.is_board_pin()
-                    and (pin.adc_num & (1 << (adc_num - 1)))
-                    and (pin.adc_channel == channel)
-                ):
-                    print("  &pin_{:s}_obj, // {:d}".format(pin.cpu_pin_name(), channel))
-                    adc_found = True
-                    break
-            if not adc_found:
-                print("  NULL,    // {:d}".format(channel))
-            if channel == 16:
-                print("#endif")
-        print("};")
+        adc_pins = {}
+        for named_pin in self.cpu_pins:
+            pin = named_pin.pin()
+            if (
+                pin.is_board_pin()
+                and not named_pin.is_hidden()
+                and (pin.adc_num & (1 << (adc_num - 1)))
+            ):
+                adc_pins[pin.adc_channel] = pin
+        if adc_pins:
+            table_size = max(adc_pins) + 1
+            self.adc_table_size[adc_num] = table_size
+            print("")
+            print("const pin_obj_t * const pin_adc{:d}[{:d}] = {{".format(adc_num, table_size))
+            for channel in range(table_size):
+                if channel in adc_pins:
+                    obj = "&pin_{:s}_obj".format(adc_pins[channel].cpu_pin_name())
+                else:
+                    obj = "NULL"
+                print("  [{:d}] = {},".format(channel, obj))
+            print("};")
 
     def print_header(self, hdr_filename, obj_decls):
         with open(hdr_filename, "wt") as hdr_file:
@@ -382,9 +383,12 @@ class Pins(object):
                     pin = named_pin.pin()
                     if pin.is_board_pin():
                         pin.print_header(hdr_file)
-                hdr_file.write("extern const pin_obj_t * const pin_adc1[];\n")
-                hdr_file.write("extern const pin_obj_t * const pin_adc2[];\n")
-                hdr_file.write("extern const pin_obj_t * const pin_adc3[];\n")
+                for adc_num, table_size in self.adc_table_size.items():
+                    hdr_file.write(
+                        "extern const pin_obj_t * const pin_adc{:d}[{:d}];\n".format(
+                            adc_num, table_size
+                        )
+                    )
             # provide #define's mapping board to cpu name
             for named_pin in self.board_pins:
                 hdr_file.write(
@@ -569,9 +573,8 @@ def main():
         with open(args.prefix_filename, "r") as prefix_file:
             print(prefix_file.read())
     pins.print()
-    pins.print_adc(1)
-    pins.print_adc(2)
-    pins.print_adc(3)
+    for i in range(1, 4):
+        pins.print_adc(i)
     pins.print_header(args.hdr_filename, args.hdr_obj_decls)
     pins.print_qstr(args.qstr_filename)
     pins.print_af_hdr(args.af_const_filename)