NANO130: Remove unnecessary synchronization in analog-in HAL

Driver AnalogIn has done with it, so remove synchronization in analog-in HAL.

Author: ccli8

targets/TARGET_NUVOTON/TARGET_NANO100/analogin_api.c

@@ -25,7 +25,6 @@
 #include "nu_modutil.h"
 
 static uint32_t adc_modinit_mask = 0;
-volatile int adc_busy_flag = 0;
 
 static const struct nu_modinit_s adc_modinit_tab[] = {
     {ADC_0_0, ADC_MODULE, CLK_CLKSEL1_ADC_S_HIRC, CLK_ADC_CLK_DIVIDER(1), ADC_RST, ADC_IRQn, NULL},
@@ -58,13 +57,7 @@ void analogin_init(analogin_t *obj, PinName pin)
 
     ADC_T *adc_base = (ADC_T *) NU_MODBASE(obj->adc);
     uint32_t chn =  NU_MODSUBINDEX(obj->adc);
-    
-    // Wait for ADC is not busy, due to all ADC channels share the same module
-    while (adc_busy_flag != 0) {
-        wait_us(100);
-    }
-    adc_busy_flag = 1;
-    
+
     // NOTE: All channels (identified by ADCName) share a ADC module. This reset will also affect other channels of the same ADC module.
     if (! adc_modinit_mask) {
         // Select clock source of paired channels
@@ -88,10 +81,8 @@ void analogin_init(analogin_t *obj, PinName pin)
         // Just enable channel N
         adc_base->CHEN |= 1 << chn;
     }
-    
+
     adc_modinit_mask |= 1 << chn;
-    
-    adc_busy_flag = 0;
 }
 
 void analogin_free(analogin_t *obj)
@@ -104,12 +95,6 @@ void analogin_free(analogin_t *obj)
 
     ADC_T *adc_base = (ADC_T *) NU_MODBASE(obj->adc);
 
-    // Wait for ADC is not busy, due to all ADC channels share the same module
-    while (adc_busy_flag != 0) {
-        wait_us(100);
-    }
-    adc_busy_flag = 1;
-
     /* Channel-level windup from here */
 
     /* Mark channel free */
@@ -132,8 +117,6 @@ void analogin_free(analogin_t *obj)
         CLK_DisableModuleClock(modinit->clkidx);
     }
 
-    adc_busy_flag = 0;
-
     /* Free up pins */
     gpio_set(obj->pin);
     obj->pin = NC;
@@ -143,27 +126,19 @@ uint16_t analogin_read_u16(analogin_t *obj)
 {
     ADC_T *adc_base = (ADC_T *) NU_MODBASE(obj->adc);
     uint32_t chn =  NU_MODSUBINDEX(obj->adc);
-    
-    // Wait for ADC is not busy, due to all ADC channels share the same module
-    while (adc_busy_flag != 0) {
-        wait_us(100);
-    }
-    adc_busy_flag = 1;
-    
+
     // Start the A/D conversion
     adc_base->CR |= ADC_CR_ADST_Msk;
     // Wait for conversion finish
     while (! ADC_GET_INT_FLAG(adc_base, ADC_ADF_INT) & ADC_ADF_INT) ;
     ADC_CLR_INT_FLAG(ADC, ADC_ADF_INT);
     uint16_t conv_res_12 = ADC_GET_CONVERSION_DATA(adc_base, chn);
-    
-    adc_busy_flag = 0;
-    
+
     // Just 12 bits are effective. Convert to 16 bits.
     // conv_res_12: 0000 b11b10b9b8 b7b6b5b4 b3b2b1b0
     // conv_res_16: b11b10b9b8 b7b6b5b4 b3b2b1b0 b11b10b9b8
     uint16_t conv_res_16 = (conv_res_12 << 4) | (conv_res_12 >> 8);
-    
+
     return conv_res_16;
 }