mimxrt/machine_adc: Add the ADC class to the machine module.

This adds the machine.ADC class with the read_u16() method.  make-pins.py
and supporting files are updated to generate ADC information.

8 files changed, 223 insertions, 12 deletions

diff --git a/ports/mimxrt/Makefile b/ports/mimxrt/Makefile
index de7b9fd3e..cacbcc1a3 100644
--- a/ports/mimxrt/Makefile
+++ b/ports/mimxrt/Makefile
@@ -111,10 +111,11 @@ SRC_TINYUSB_C += \
 	lib/tinyusb/src/class/vendor/vendor_device.c \
 	lib/tinyusb/src/portable/nxp/transdimension/dcd_transdimension.c
 
-SRC_TINYUSB_IMX_C += \
+SRC_HAL_IMX_C += \
 	$(MCU_DIR)/system_$(MCU_SERIES).c \
 	$(MCU_DIR)/xip/fsl_flexspi_nor_boot.c \
 	$(MCU_DIR)/project_template/clock_config.c \
+	$(MCU_DIR)/drivers/fsl_adc.c \
 	$(MCU_DIR)/drivers/fsl_clock.c \
 	$(MCU_DIR)/drivers/fsl_gpio.c \
 	$(MCU_DIR)/drivers/fsl_gpt.c \
@@ -134,6 +135,7 @@ SRC_C = \
 	tusb_port.c \
 	board_init.c \
 	$(BOARD_DIR)/flash_config.c \
+	machine_adc.c \
 	machine_led.c \
 	machine_pin.c \
 	machine_rtc.c \
@@ -155,7 +157,7 @@ SRC_C = \
 	drivers/bus/softspi.c \
 	extmod/modonewire.c \
 	$(SRC_TINYUSB_C) \
-	$(SRC_TINYUSB_IMX_C) \
+	$(SRC_HAL_IMX_C) \
 
 ifeq ($(MICROPY_FLOAT_IMPL),double)
 LIBM_SRC_C += $(addprefix lib/libm_dbl/,\
@@ -256,6 +258,7 @@ SRC_S = lib/utils/gchelper_m3.s \
 
 # List of sources for qstr extraction
 SRC_QSTR += \
+	machine_adc.c \
 	machine_led.c \
 	machine_pin.c \
 	machine_rtc.c \
diff --git a/ports/mimxrt/board_init.c b/ports/mimxrt/board_init.c
index 01f6848ea..65024ff3e 100644
--- a/ports/mimxrt/board_init.c
+++ b/ports/mimxrt/board_init.c
@@ -80,6 +80,9 @@ void board_init(void) {
     //  CLOCK_EnableUsbhs1PhyPllClock(kCLOCK_Usbphy480M, 480000000U);
     //  CLOCK_EnableUsbhs1Clock(kCLOCK_Usb480M, 480000000U);
 
+    // ADC
+    machine_adc_init();
+
     // PIT
     machine_timer_init_PIT();
 }
diff --git a/ports/mimxrt/boards/make-pins.py b/ports/mimxrt/boards/make-pins.py
index 5e5b81e31..e9e32a504 100644
--- a/ports/mimxrt/boards/make-pins.py
+++ b/ports/mimxrt/boards/make-pins.py
@@ -6,9 +6,11 @@ from __future__ import print_function
 import argparse
 import sys
 import csv
+import re
 
 SUPPORTED_AFS = {"GPIO"}
 MAX_AF = 10  # AF0 .. AF9
+ADC_COL = 11
 
 
 def parse_pad(pad_str):
@@ -38,7 +40,7 @@ class Pin(object):
         self.gpio = gpio
         self.pin = pin
         self.alt_fn = []
-        self.adc_channel = 0
+        self.adc_fns = []
         self.board_pin = False
 
     def set_is_board_pin(self):
@@ -48,7 +50,13 @@ class Pin(object):
         return self.board_pin
 
     def parse_adc(self, adc_str):
-        pass
+        adc_regex = r"ADC(?P<instance>\d*)_IN(?P<channel>\d*)"
+
+        matches = re.finditer(adc_regex, adc_str, re.MULTILINE)
+        for match in matches:
+            self.adc_fns.append(
+                AdcFunction(instance=match.group("instance"), channel=match.group("channel"))
+            )
 
     def parse_af(self, af_idx, af_strs_in):
         pass
@@ -69,14 +77,34 @@ class Pin(object):
         else:
             raise ValueError("Pin '{}' has no alternative functions".format(self.name))
 
+    def print_pin_adc(self):
+        if self.adc_fns:
+            print(
+                "static const machine_pin_adc_obj_t pin_{0}_adc[{1}] = {{".format(
+                    self.name, len(self.adc_fns)
+                )
+            )
+            for adc_fn in self.adc_fns:
+                adc_fn.print()
+            print("};")
+
     def print(self):
         if self.alt_fn:
             self.print_pin_af()
-            print(
-                "const machine_pin_obj_t pin_{0} = PIN({0}, {1}, {2}, pin_{3});\n".format(
-                    self.name, self.gpio, int(self.pin), self.name + "_af"
+            self.print_pin_adc()
+
+            if self.adc_fns:
+                print(
+                    "const machine_pin_obj_t pin_{0} = PIN({0}, {1}, {2}, pin_{0}_af, {3}, pin_{0}_adc);\n".format(
+                        self.name, self.gpio, int(self.pin), len(self.adc_fns)
+                    )
+                )
+            else:
+                print(
+                    "const machine_pin_obj_t pin_{0} = PIN({0}, {1}, {2}, pin_{0}_af, {3}, NULL);\n".format(
+                        self.name, self.gpio, int(self.pin), len(self.adc_fns)
+                    )
                 )
-            )
         else:
             raise ValueError("Pin '{}' has no alternative functions".format(self.name))
 
@@ -84,6 +112,18 @@ class Pin(object):
         pass
 
 
+class AdcFunction(object):
+    """Holds the information associated with a pins ADC function."""
+
+    def __init__(self, instance, channel):
+        self.instance = instance
+        self.channel = channel
+
+    def print(self):
+        """Prints the C representation of this AF."""
+        print(f"    PIN_ADC(ADC{self.instance}, {self.channel}),")
+
+
 class AlternateFunction(object):
     """Holds the information associated with a pins alternate function."""
 
@@ -149,6 +189,8 @@ class Pins(object):
                     if af and af_supported(af):
                         pin.add_af(AlternateFunction(af_idx, af))
 
+                pin.parse_adc(row[ADC_COL])
+
                 self.cpu_pins.append(pin)
 
     @staticmethod
diff --git a/ports/mimxrt/boards/mimxrt_prefix.c b/ports/mimxrt/boards/mimxrt_prefix.c
index 59e338976..96ba6a0d5 100644
--- a/ports/mimxrt/boards/mimxrt_prefix.c
+++ b/ports/mimxrt/boards/mimxrt_prefix.c
@@ -13,7 +13,13 @@
         .pad_config = (uint32_t)(_pad_config), \
     } \
 
-#define PIN(_name, _gpio, _pin, _af_list) \
+#define PIN_ADC(_instance, _channel) \
+    { \
+        .instance = (_instance), \
+        .channel = (_channel) \
+    } \
+
+#define PIN(_name, _gpio, _pin, _af_list, _adc_list_len, _adc_list) \
     { \
         .base = { &machine_pin_type }, \
         .name = MP_QSTR_##_name, \
@@ -21,6 +27,8 @@
         .pin = (uint32_t)(_pin), \
         .muxRegister = (uint32_t)&(IOMUXC->SW_MUX_CTL_PAD[kIOMUXC_SW_MUX_CTL_PAD_##_name]), \
         .configRegister = (uint32_t)&(IOMUXC->SW_PAD_CTL_PAD[kIOMUXC_SW_PAD_CTL_PAD_##_name]), \
-        .af_list_len = (size_t)(sizeof((_af_list)) / sizeof(machine_pin_af_obj_t)), \
+        .af_list_len = (uint8_t)(sizeof((_af_list)) / sizeof(machine_pin_af_obj_t)), \
+        .adc_list_len = (_adc_list_len), \
         .af_list = (_af_list), \
+        .adc_list = (_adc_list), \
     } \
diff --git a/ports/mimxrt/machine_adc.c b/ports/mimxrt/machine_adc.c
new file mode 100644
index 000000000..8bf5e7b9a
--- /dev/null
+++ b/ports/mimxrt/machine_adc.c
@@ -0,0 +1,145 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2021 Philipp Ebensberger
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdint.h>
+#include "py/obj.h"
+#include "py/runtime.h"
+#include "py/mphal.h"
+
+#include "fsl_adc.h"
+#include "fsl_gpio.h"
+#include "fsl_iomuxc.h"
+
+#include "modmachine.h"
+
+typedef struct _machine_adc_obj_t {
+    mp_obj_base_t base;
+    ADC_Type *adc;
+    uint8_t channel;
+    uint8_t channel_group;
+    uint16_t resolution;
+} machine_adc_obj_t;
+
+STATIC ADC_Type *const adc_bases[] = ADC_BASE_PTRS;
+
+STATIC void adc_obj_print(const mp_print_t *print, mp_obj_t o, mp_print_kind_t kind) {
+    (void)kind;
+    machine_adc_obj_t *self = MP_OBJ_TO_PTR(o);
+
+    // 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);
+            break;
+        }
+    }
+}
+
+STATIC mp_obj_t adc_obj_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
+    mp_arg_check_num(n_args, n_kw, 1, 1, false);
+
+    // Unpack and check parameter
+    const machine_pin_obj_t *pin = pin_find(args[0]);
+
+    if (pin->adc_list_len == 0) {
+        mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("Pin(%q) does not have ADC capabilities"), pin->name);
+    }
+
+    // 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;
+
+    // Configure ADC peripheral channel
+    adc_channel_config_t channel_config = {
+        .channelNumber = (uint32_t)channel,
+        .enableInterruptOnConversionCompleted = false,
+    };
+    ADC_SetChannelConfig(adc_instance, 0UL, &channel_config);  // NOTE: we always choose channel group '0' since we only perform software triggered conversion
+
+    // Create ADC Instance
+    machine_adc_obj_t *o = m_new_obj(machine_adc_obj_t);
+    o->base.type = &machine_adc_type;
+    o->adc = adc_instance;
+    o->channel = (uint8_t)channel;
+    o->channel_group = 0;
+    o->resolution = 4096;  // NOTE: currently only 12bit resolution supported
+
+    return MP_OBJ_FROM_PTR(o);
+}
+
+// read_u16()
+STATIC mp_obj_t machine_adc_read_u16(mp_obj_t self_in) {
+    machine_adc_obj_t *self = MP_OBJ_TO_PTR(self_in);
+
+    // Initiate conversion
+    adc_channel_config_t channel_config = {
+        .channelNumber = self->channel,
+        .enableInterruptOnConversionCompleted = false,
+    };
+    ADC_SetChannelConfig(self->adc, (uint32_t)self->channel_group, &channel_config);
+
+    // Wait for conversion to finish
+    while (!ADC_GetChannelStatusFlags(self->adc, (uint32_t)self->channel_group)) {
+        // do nothing
+    }
+
+    // Measure input voltage
+    uint32_t value = ADC_GetChannelConversionValue(self->adc, (uint32_t)self->channel_group);
+    return MP_OBJ_NEW_SMALL_INT(value * 65535 / self->resolution);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_adc_read_u16_obj, machine_adc_read_u16);
+
+STATIC const mp_rom_map_elem_t adc_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_read_u16), MP_ROM_PTR(&machine_adc_read_u16_obj) },
+};
+
+STATIC MP_DEFINE_CONST_DICT(adc_locals_dict, adc_locals_dict_table);
+
+const mp_obj_type_t machine_adc_type = {
+    {&mp_type_type},
+    .name = MP_QSTR_ADC,
+    .print = adc_obj_print,
+    .make_new = adc_obj_make_new,
+    .locals_dict = (mp_obj_dict_t *)&adc_locals_dict,
+};
+
+void machine_adc_init(void) {
+    for (int i = 1; i < sizeof(adc_bases) / sizeof(ADC_Type *); ++i) {
+        ADC_Type *adc_instance = adc_bases[i];
+
+        // Configure ADC perpheral
+        adc_config_t config;
+        ADC_GetDefaultConfig(&config);
+        ADC_Init(adc_instance, &config);
+
+        // Perform calibration
+        status_t calib_state = ADC_DoAutoCalibration(adc_instance);
+
+        if (calib_state == kStatus_Fail) {
+            mp_printf(&mp_plat_print, "Calibration for ADC Instance %d failed", i);
+        }
+    }
+}
diff --git a/ports/mimxrt/modmachine.c b/ports/mimxrt/modmachine.c
index 96cae3a82..dfee91992 100644
--- a/ports/mimxrt/modmachine.c
+++ b/ports/mimxrt/modmachine.c
@@ -59,6 +59,7 @@ STATIC const mp_rom_map_elem_t machine_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_LED),                 MP_ROM_PTR(&machine_led_type) },
     #endif
     { MP_ROM_QSTR(MP_QSTR_Pin),                 MP_ROM_PTR(&machine_pin_type) },
+    { MP_ROM_QSTR(MP_QSTR_ADC),                 MP_ROM_PTR(&machine_adc_type) },
     { MP_ROM_QSTR(MP_QSTR_Timer),               MP_ROM_PTR(&machine_timer_type) },
     { MP_ROM_QSTR(MP_QSTR_RTC),                 MP_ROM_PTR(&machine_rtc_type) },
     { MP_ROM_QSTR(MP_QSTR_Signal),              MP_ROM_PTR(&machine_signal_type) },
diff --git a/ports/mimxrt/modmachine.h b/ports/mimxrt/modmachine.h
index d165c00e6..a7b577fa7 100644
--- a/ports/mimxrt/modmachine.h
+++ b/ports/mimxrt/modmachine.h
@@ -29,9 +29,11 @@
 
 #include "py/obj.h"
 
+extern const mp_obj_type_t machine_adc_type;
 extern const mp_obj_type_t machine_timer_type;
 extern const mp_obj_type_t machine_rtc_type;
 
+void machine_adc_init(void);
 void machine_timer_init_PIT(void);
 
 #endif // MICROPY_INCLUDED_MIMXRT_MODMACHINE_H
diff --git a/ports/mimxrt/pin.h b/ports/mimxrt/pin.h
index 6afedd1f5..7a05d2d64 100644
--- a/ports/mimxrt/pin.h
+++ b/ports/mimxrt/pin.h
@@ -101,14 +101,21 @@ typedef struct {
 } machine_pin_af_obj_t;
 
 typedef struct {
+    ADC_Type *instance;
+    uint8_t channel;
+} machine_pin_adc_obj_t;
+
+typedef struct {
     mp_obj_base_t base;
     qstr name;  // pad name
     GPIO_Type *gpio;  // gpio instance for pin
     uint32_t pin;  // pin number
     uint32_t muxRegister;
     uint32_t configRegister;
-    size_t af_list_len;  // length of available alternate functions list
-    const machine_pin_af_obj_t *af_list;  // pointer tolist with alternate functions
+    uint8_t af_list_len;  // length of available alternate functions list
+    uint8_t adc_list_len; // length of available ADC options list
+    const machine_pin_af_obj_t *af_list;  // pointer to list with alternate functions
+    const machine_pin_adc_obj_t *adc_list; // pointer to list with ADC options
 } machine_pin_obj_t;
 
 // ------------------------------------------------------------------------------------------------------------------ //