[M252KG] Free up peripheral pins in peripheral free-up HAL API

Without free-up of peripheral pins, peripheral pins of the same peripheral may
share by multiple ports after port iteration, and this peripheral may fail with
pin interference.

Author: ccli8

targets/TARGET_NUVOTON/TARGET_M251/analogin_api.c

@@ -55,6 +55,8 @@ void analogin_init(analogin_t *obj, PinName pin)
     MBED_ASSERT(modinit != NULL);
     MBED_ASSERT(modinit->modname == (int) obj->adc);
 
+    obj->pin = pin;
+
     // Wire pinout
     pinmap_pinout(pin, PinMap_ADC);
 

targets/TARGET_NUVOTON/TARGET_M251/analogout_api.c

@@ -53,6 +53,8 @@ void analogout_init(dac_t *obj, PinName pin)
     uint32_t chn =  NU_MODSUBINDEX(obj->dac);
     MBED_ASSERT(chn < NU_DACCHN_MAXNUM);
 
+    obj->pin = pin;
+
     /* Wire pinout */
     pinmap_pinout(pin, PinMap_DAC);
 
@@ -119,6 +121,10 @@ void analogout_free(dac_t *obj)
         /* Disable IP clock */
         CLK_DisableModuleClock(modinit->clkidx);
     }
+    
+    // Free up pins
+    gpio_set(obj->pin);
+    obj->pin = NC;
 }
 
 void analogout_write(dac_t *obj, float value)

targets/TARGET_NUVOTON/TARGET_M251/i2c_api.c

@@ -99,6 +99,9 @@ void i2c_init(i2c_t *obj, PinName sda, PinName scl)
     MBED_ASSERT(modinit != NULL);
     MBED_ASSERT(modinit->modname == (int) obj->i2c.i2c);
 
+    obj->i2c.pin_sda = sda;
+    obj->i2c.pin_scl = scl;
+
     pinmap_pinout(sda, PinMap_I2C_SDA);
     pinmap_pinout(scl, PinMap_I2C_SCL);
 

targets/TARGET_NUVOTON/TARGET_M251/objects.h

@@ -44,14 +44,20 @@ struct port_s {
 
 struct analogin_s {
     ADCName adc;
+    PinName pin;
 };
 
 struct dac_s {
     DACName dac;
+    PinName pin;
 };
 
 struct serial_s {
     UARTName uart;
+    PinName pin_tx;
+    PinName pin_rx;
+    PinName pin_rts;
+    PinName pin_cts;
 
     uint32_t baudrate;
     uint32_t databits;
@@ -91,6 +97,8 @@ struct spi_s {
 
 struct i2c_s {
     I2CName     i2c;
+    PinName     pin_sda;
+    PinName     pin_scl;
     int         slaveaddr_state;
 
     uint32_t    tran_ctrl;
@@ -109,6 +117,7 @@ struct i2c_s {
 
 struct pwmout_s {
     PWMName pwm;
+    PinName pin;
     uint32_t period_us;
     uint32_t pulsewidth_us;
 };

targets/TARGET_NUVOTON/TARGET_M251/pwmout_api.c

@@ -70,6 +70,8 @@ void pwmout_init(pwmout_t* obj, PinName pin)
     MBED_ASSERT(modinit != NULL);
     MBED_ASSERT(modinit->modname == (int) obj->pwm);
 
+    obj->pin = pin;
+
     // Wire pinout
     pinmap_pinout(pin, PinMap_PWM);
 
@@ -120,6 +122,10 @@ void pwmout_free(pwmout_t* obj)
     // Mark this module to be deinited.
     int i = modinit - pwm_modinit_tab;
     pwm_modinit_mask &= ~(1 << i);
+
+    // Free up pins
+    gpio_set(obj->pin);
+    obj->pin = NC;
 }
 
 void pwmout_write(pwmout_t* obj, float value)

targets/TARGET_NUVOTON/TARGET_M251/serial_api.c

@@ -156,10 +156,15 @@ void serial_init(serial_t *obj, PinName tx, PinName rx)
 
     struct nu_uart_var *var = (struct nu_uart_var *) modinit->var;
 
-    if (! var->ref_cnt) {
-        pinmap_pinout(tx, PinMap_UART_TX);
-        pinmap_pinout(rx, PinMap_UART_RX);
+    obj->serial.pin_tx = tx;
+    obj->serial.pin_rx = rx;
+    obj->serial.pin_rts = NC;
+    obj->serial.pin_cts = NC;
+    
+    pinmap_pinout(tx, PinMap_UART_TX);
+    pinmap_pinout(rx, PinMap_UART_RX);
 
+    if (! var->ref_cnt) {
         // Select IP clock source
         CLK_SetModuleClock(modinit->clkidx, modinit->clksrc, modinit->clkdiv);
         // Enable IP clock
@@ -259,6 +264,16 @@ void serial_free(serial_t *obj)
         int i = modinit - uart_modinit_tab;
         uart_modinit_mask &= ~(1 << i);
     }
+
+    // Free up pins
+    gpio_set(obj->serial.pin_tx);
+    gpio_set(obj->serial.pin_rx);
+    gpio_set(obj->serial.pin_rts);
+    gpio_set(obj->serial.pin_cts);
+    obj->serial.pin_tx = NC;
+    obj->serial.pin_rx = NC;
+    obj->serial.pin_rts = NC;
+    obj->serial.pin_cts = NC;
 }
 
 void serial_baud(serial_t *obj, int baudrate)
@@ -305,6 +320,16 @@ void serial_set_flow_control(serial_t *obj, FlowControl type, PinName rxflow, Pi
 {
     UART_T *uart_base = (UART_T *) NU_MODBASE(obj->serial.uart);
 
+    // Free up old rts/cts pins when they are different from new ones
+    if (obj->serial.pin_rts != rxflow) {
+        gpio_set(obj->serial.pin_rts);
+        obj->serial.pin_rts = rxflow;
+    }
+    if (obj->serial.pin_cts != txflow) {
+        gpio_set(obj->serial.pin_cts);
+        obj->serial.pin_cts = txflow;
+    }
+
     if (rxflow != NC) {
         // Check if RTS pin matches.
         uint32_t uart_rts = pinmap_peripheral(rxflow, PinMap_UART_RTS);

targets/TARGET_NUVOTON/TARGET_M251/spi_api.c

@@ -120,6 +120,11 @@ void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel
     MBED_ASSERT(modinit != NULL);
     MBED_ASSERT(modinit->modname == (int) obj->spi.spi);
 
+    obj->spi.pin_mosi = mosi;
+    obj->spi.pin_miso = miso;
+    obj->spi.pin_sclk = sclk;
+    obj->spi.pin_ssel = ssel;
+
     pinmap_pinout(mosi, PinMap_SPI_MOSI);
     pinmap_pinout(miso, PinMap_SPI_MISO);
     pinmap_pinout(sclk, PinMap_SPI_SCLK);
@@ -133,12 +138,6 @@ void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel
     // Reset this module
     SYS_ResetModule(modinit->rsetidx);
 
-    obj->spi.pin_mosi = mosi;
-    obj->spi.pin_miso = miso;
-    obj->spi.pin_sclk = sclk;
-    obj->spi.pin_ssel = ssel;
-
-
 #if DEVICE_SPI_ASYNCH
     obj->spi.dma_usage = DMA_USAGE_NEVER;
     obj->spi.event = 0;
@@ -184,6 +183,16 @@ void spi_free(spi_t *obj)
     // Mark this module to be deinited.
     int i = modinit - spi_modinit_tab;
     spi_modinit_mask &= ~(1 << i);
+    
+    // Free up pins
+    gpio_set(obj->spi.pin_mosi);
+    gpio_set(obj->spi.pin_miso);
+    gpio_set(obj->spi.pin_sclk);
+    gpio_set(obj->spi.pin_ssel);
+    obj->spi.pin_mosi = NC;
+    obj->spi.pin_miso = NC;
+    obj->spi.pin_sclk = NC;
+    obj->spi.pin_ssel = NC;
 }
 
 void spi_format(spi_t *obj, int bits, int mode, int slave)