Initial WIP ADC support.

Signed-off-by: Yilin Sun <imi415@imi.moe>

CMakeLists.txt

@@ -65,6 +65,7 @@ set(TARGET_SOURCES
     "src/app_aux_ctrl.c"
     "src/app_mrb_repl.c"
     "src/app_syscalls.c"
+    "src/mrb_machine_impl/mrb_machine_adc_impl.c"
     "src/mrb_machine_impl/mrb_machine_gpio_impl.c"
     "src/main.c"
 )

lib/mruby

@@ -1 +1 @@
-Subproject commit 12b520e7873432d7135f9de86330c000f8464873
+Subproject commit 7f0aca015ec2bcad7d08d912163f135bdb238149

src/mrb_machine_impl/mrb_machine_adc_impl.c

@@ -0,0 +1,127 @@
+#include <stdio.h>
+
+/* Board */
+#include "board.h"
+
+/* SDK drivers */
+#include "fsl_anactrl.h"
+#include "fsl_clock.h"
+#include "fsl_gpio.h"
+#include "fsl_iocon.h"
+#include "fsl_lpadc.h"
+#include "fsl_power.h"
+
+/* FreeRTOS */
+#include "FreeRTOS.h"
+#include "semphr.h"
+
+/* Gem private */
+#include "machine-adc/src/adc.h"
+
+#define ADC_IMPL_PORT(x) (x / 32)
+#define ADC_IMPL_PIN(x)  (x % 32)
+
+#define ADC_EXT_CHANNEL_COUNT 10
+#define ADC_TEMP_CHANNEL      26
+
+/* CH0A, CH0B, CH1A, CH1B, ... CH4A, CH4B */
+const static uint32_t s_adc_pin_table[ADC_EXT_CHANNEL_COUNT] = {
+    23, 16, 10, 11, 15, 12, 31, 32, 40, 41,
+};
+
+static bool              s_adc_initialized = false;
+static SemaphoreHandle_t s_adc_semaphore   = NULL;
+
+static void mrb_machine_adc_impl_init_peripheral(void) {
+    CLOCK_SetClkDiv(kCLOCK_DivAdcAsyncClk, 8, true);
+    CLOCK_AttachClk(kMAIN_CLK_to_ADC_CLK);
+
+    POWER_DisablePD(kPDRUNCFG_PD_LDOGPADC);
+
+    ANACTRL_Init(ANACTRL);
+    ANACTRL_EnableVref1V(ANACTRL, true);
+
+    lpadc_config_t adc_cfg;
+    LPADC_GetDefaultConfig(&adc_cfg);
+
+    adc_cfg.enableAnalogPreliminary = true;
+    adc_cfg.referenceVoltageSource  = kLPADC_ReferenceVoltageAlt2;
+    adc_cfg.conversionAverageMode   = kLPADC_ConversionAverage128;
+
+    LPADC_Init(ADC0, &adc_cfg);
+    LPADC_DoOffsetCalibration(ADC0);
+    LPADC_DoAutoCalibration(ADC0);
+}
+
+int mrb_machine_adc_impl_config(uint32_t pin) {
+    if (!s_adc_initialized) {
+        mrb_machine_adc_impl_init_peripheral();
+
+        s_adc_semaphore = xSemaphoreCreateBinary();
+        if (s_adc_semaphore == NULL) {
+            return -1;
+        }
+
+        s_adc_initialized = true;
+    }
+
+    uint32_t iocon_mode = IOCON_PIO_ASW(1);
+
+    /* Configure IOCON only if this is an external channel */
+    if (pin < ADC_EXT_CHANNEL_COUNT) {
+        IOCON_PinMuxSet(IOCON, ADC_IMPL_PORT(s_adc_pin_table[pin]), ADC_IMPL_PIN(s_adc_pin_table[pin]), iocon_mode);
+    }
+
+    return 0;
+}
+
+int mrb_machine_adc_impl_read(uint32_t pin) {
+    lpadc_conv_command_config_t conv_cfg;
+    lpadc_conv_trigger_config_t trig_cfg;
+
+    LPADC_GetDefaultConvCommandConfig(&conv_cfg);
+    LPADC_GetDefaultConvTriggerConfig(&trig_cfg);
+
+    conv_cfg.conversionResolutionMode = kLPADC_ConversionResolutionHigh;
+
+    if (pin < ADC_EXT_CHANNEL_COUNT) {
+        /* This is an external channel, Positive and negative pair shares the same channel */
+
+        lpadc_sample_channel_mode_t mode;
+        if ((pin % 2) == 0) {
+            mode = kLPADC_SampleChannelSingleEndSideA;
+        } else {
+            mode = kLPADC_SampleChannelSingleEndSideB;
+        }
+
+        conv_cfg.channelNumber     = pin / 2;
+        conv_cfg.sampleChannelMode = mode;
+    } else if (pin == ADC_TEMP_CHANNEL) { /* Temperature channel requires differential sampling */
+        conv_cfg.channelNumber     = pin;
+        conv_cfg.sampleChannelMode = kLPADC_SampleChannelDiffBothSide;
+    } else { /* Other internal channels */
+        conv_cfg.channelNumber     = pin;
+        conv_cfg.sampleChannelMode = kLPADC_SampleChannelSingleEndSideA;
+    }
+
+    trig_cfg.targetCommandId       = 15;
+    trig_cfg.enableHardwareTrigger = false;
+
+    LPADC_SetConvCommandConfig(ADC0, 15, &conv_cfg);
+    LPADC_SetConvTriggerConfig(ADC0, 0U, &trig_cfg);
+
+    LPADC_EnableInterrupts(ADC0, kLPADC_FIFO0WatermarkInterruptEnable);
+    EnableIRQ(ADC0_IRQn);
+
+    return 0;
+}
+
+void ADC0_IRQHandler(void) {
+    BaseType_t higher_priority_woken = pdFALSE;
+
+    xSemaphoreGiveFromISR(s_adc_semaphore, &higher_priority_woken);
+
+    if (higher_priority_woken) {
+        portYIELD_FROM_ISR(higher_priority_woken);
+    }
+}