Allow NC for MISO or MOSI while initializing SPI

Static pinmap extension required to use pin_function() and pin_mode() functions instead of pinmap_pinout(). Unfortunatelly pin_function() does not allow passing NC pin.
Call pin_function() and pin_mode() only if MISO/MOSI pin is not NC.

Author: mprse

targets/TARGET_Freescale/TARGET_MCUXpresso_MCUS/TARGET_MCU_K64F/spi_api.c

@@ -42,10 +42,13 @@ SPIName spi_get_peripheral_name(PinName mosi, PinName miso, PinName sclk)
 
     SPIName spi_per;
 
-    // If 3 wire SPI is used, the miso is not connected.
+    // MISO or MOSI may be not connected
     if (miso == NC) {
         spi_per = (SPIName)pinmap_merge(spi_mosi, spi_sclk);
-    } else {
+    } else if (mosi == NC) {
+        spi_per = (SPIName)pinmap_merge(spi_miso, spi_sclk);
+    }
+    else {
         SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
         spi_per = (SPIName)pinmap_merge(spi_data, spi_sclk);
     }
@@ -59,10 +62,14 @@ void spi_init_direct(spi_t *obj, const spi_pinmap_t *pinmap)
     MBED_ASSERT((int)obj->spi.instance != NC);
 
     // pin out the spi pins
-    pin_function(pinmap->mosi_pin, pinmap->mosi_function);
-    pin_mode(pinmap->mosi_pin, PullNone);
-    pin_function(pinmap->miso_pin, pinmap->miso_function);
-    pin_mode(pinmap->miso_pin, PullNone);
+    if (pinmap->mosi_pin != NC) {
+        pin_function(pinmap->mosi_pin, pinmap->mosi_function);
+        pin_mode(pinmap->mosi_pin, PullNone);
+    }
+    if (pinmap->miso_pin != NC) {
+        pin_function(pinmap->miso_pin, pinmap->miso_function);
+        pin_mode(pinmap->miso_pin, PullNone);
+    }
     pin_function(pinmap->sclk_pin, pinmap->sclk_function);
     pin_mode(pinmap->sclk_pin, PullNone);
     if (pinmap->ssel_pin != NC) {

targets/TARGET_NXP/TARGET_MCUXpresso_MCUS/TARGET_LPC/spi_api.c

@@ -90,10 +90,14 @@ static void _spi_init_direct(spi_t *obj, const spi_pinmap_t *pinmap)
     }
 
     // pin out the spi pins
-    pin_function(pinmap->mosi_pin, pinmap->mosi_function);
-    pin_mode(pinmap->mosi_pin, PullNone);
-    pin_function(pinmap->miso_pin, pinmap->miso_function);
-    pin_mode(pinmap->miso_pin, PullNone);
+    if (pinmap->mosi_pin != NC) {
+        pin_function(pinmap->mosi_pin, pinmap->mosi_function);
+        pin_mode(pinmap->mosi_pin, PullNone);
+    }
+    if (pinmap->miso_pin != NC) {
+        pin_function(pinmap->miso_pin, pinmap->miso_function);
+        pin_mode(pinmap->miso_pin, PullNone);
+    }
     pin_function(pinmap->sclk_pin, pinmap->sclk_function);
     pin_mode(pinmap->sclk_pin, PullNone);
     if (pinmap->ssel_pin != NC) {

targets/TARGET_STM/stm_spi_api.c

@@ -147,9 +147,11 @@ SPIName spi_get_peripheral_name(PinName mosi, PinName miso, PinName sclk)
 
     SPIName spi_per;
 
-    // If 3 wire SPI is used, the miso is not connected.
+    // MISO or MOSI may be not connected
     if (miso == NC) {
         spi_per = (SPIName)pinmap_merge(spi_mosi, spi_sclk);
+    } else if (mosi == NC) {
+        spi_per = (SPIName)pinmap_merge(spi_miso, spi_sclk);
     } else {
         SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
         spi_per = (SPIName)pinmap_merge(spi_data, spi_sclk);
@@ -216,10 +218,14 @@ static void _spi_init_direct(spi_t *obj, const spi_pinmap_t *pinmap)
 #endif
 
     // Configure the SPI pins
-    pin_function(pinmap->mosi_pin, pinmap->mosi_function);
-    pin_mode(pinmap->mosi_pin, PullNone);
-    pin_function(pinmap->miso_pin, pinmap->miso_function);
-    pin_mode(pinmap->miso_pin, PullNone);
+    if (pinmap->mosi_pin != NC) {
+        pin_function(pinmap->mosi_pin, pinmap->mosi_function);
+        pin_mode(pinmap->mosi_pin, PullNone);
+    }
+    if (pinmap->miso_pin != NC) {
+        pin_function(pinmap->miso_pin, pinmap->miso_function);
+        pin_mode(pinmap->miso_pin, PullNone);
+    }
     pin_function(pinmap->sclk_pin, pinmap->sclk_function);
     pin_mode(pinmap->sclk_pin, PullNone);
     spiobj->pin_miso = pinmap->miso_pin;
@@ -364,8 +370,12 @@ void spi_free(spi_t *obj)
     LL_HSEM_ReleaseLock(HSEM, CFG_HW_RCC_SEMID, HSEM_CR_COREID_CURRENT);
 #endif /* DUAL_CORE */
     // Configure GPIOs
-    pin_function(spiobj->pin_miso, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
-    pin_function(spiobj->pin_mosi, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
+    if (spiobj->pin_miso != NC) {
+        pin_function(spiobj->pin_miso, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
+    }
+    if (spiobj->pin_mosi != NC) {
+        pin_function(spiobj->pin_mosi, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
+    }
     pin_function(spiobj->pin_sclk, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
     if (handle->Init.NSS != SPI_NSS_SOFT) {
         pin_function(spiobj->pin_ssel, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));