boards/common/gd32v: cleanup default I2C and SPI config

This commit includes the following cleanups:
- The macros `I2C_DEV_1_USED` and `SPI_DEV_1_USED` are now used with the values 0 and 1. This allows to enable but also to disable the second interface even if the board definition enables it by default.
- The second I2C device `I2C_DEV(1)` and the second SPI device `SPI_DEV(1)` are now disabled by default.
- The second SPI device `SPI_DEV(1)` now uses PB5 as default CS signal instead of PA4 to keep PA4 free for ADC or DAC even if `SPI_DEV(1)` is used, for example for the TFT display.

boards/common/gd32v/include/cfg_i2c_default.h

@@ -33,11 +33,16 @@ extern "C" {
  */
 
 /**
- * @brief   Enable the second I2C device `I2C_DEV(1)` by default
+ * @brief   Disable the second I2C device `I2C_DEV(1)` by default
  *
+ * The second I2C device `I2C_DEV(1)` is only defined if `I2C_DEV_1_USED`
+ * is set to 1 by the board.
+ * This allows to use the default configuration with one or two I2C devices
+ * depending on whether other peripherals are enabled that would collide with
+ * the I2C devices.
  */
 #ifndef I2C_DEV_1_USED
-#define I2C_DEV_1_USED
+#define I2C_DEV_1_USED  0
 #endif
 
 /**
@@ -46,7 +51,7 @@ extern "C" {
  * The default I2C device configuration allows to define up to two I2C devices
  * `I2C_DEV(0)` and `I2C_DEV(1)`. `I2C_DEV(0)` is always defined if the I2C
  * peripheral is enabled by the module `periph_spi`. The second I2C device
- * `I2C_DEV(1)` is only defined if `I2C_DEV_1_USED` is defined by the board.
+ * `I2C_DEV(1)` is only defined if `I2C_DEV_1_USED` is set to 1 by the board.
  * This allows to use the default configuration with one or two I2C devices
  * depending on whether other peripherals are enabled that would collide with
  * the I2C devices.
@@ -60,6 +65,7 @@ static const i2c_conf_t i2c_config[] = {
         .rcu_mask       = RCU_APB1EN_I2C0EN_Msk,
         .irqn           = I2C0_EV_IRQn,
     },
+#if I2C_DEV_1_USED
     {
         .dev            = I2C1,
         .speed          = I2C_SPEED_NORMAL,
@@ -68,6 +74,7 @@ static const i2c_conf_t i2c_config[] = {
         .rcu_mask       = RCU_APB1EN_I2C1EN_Msk,
         .irqn           = I2C1_EV_IRQn,
     }
+#endif
 };
 
 #define I2C_NUMOF   ARRAY_SIZE(i2c_config)

boards/common/gd32v/include/cfg_spi_default.h

@@ -33,11 +33,16 @@ extern "C" {
  */
 
 /**
- * @brief   Enable the second SPI device `SPI_DEV(1)` by default
+ * @brief   Disable the second SPI device `SPI_DEV(1)` by default
  *
+ * The second SPI device `SPI_DEV(1)` is only defined if `SPI_DEV_1_USED`
+ * is set to 1 by the board.
+ * This allows to use the default configuration with one or two SPI devices
+ * depending on whether other peripherals are enabled that would collide with
+ * the SPI devices.
  */
 #ifndef SPI_DEV_1_USED
-#define SPI_DEV_1_USED
+#define SPI_DEV_1_USED  0
 #endif
 
 /**
@@ -57,7 +62,7 @@ extern "C" {
  * the default CS signal is connected to an unused hardware.
  */
 #ifndef SPI_DEV_1_CS
-#define SPI_DEV_1_CS    GPIO_PIN(PORT_A, 4)
+#define SPI_DEV_1_CS    GPIO_PIN(PORT_B, 5)
 #endif
 
 /**
@@ -66,7 +71,7 @@ extern "C" {
  * The default SPI device configuration allows to define up to two SPI devices
  * `SPI_DEV(0)` and `SPI_DEV(1)`. `SPI_DEV(0)` is always defined if the SPI
  * peripheral is enabled by the module `periph_spi`. The second SPI device
- * `SPI_DEV(1)` is only defined if `SPI_DEV_1_USED` is defined by the board.
+ * `SPI_DEV(1)` is only defined if `SPI_DEV_1_USED` is set to 1 by the board.
  * This allows to use the default configuration with one or two SPI devices
  * depending on whether other peripherals are enabled that would collide with
  * the SPI devices.
@@ -81,11 +86,11 @@ static const spi_conf_t spi_config[] = {
         .rcumask  = RCU_APB1EN_SPI1EN_Msk,
         .apbbus   = APB1,
     },
-#ifdef SPI_DEV_1_USED
+#if SPI_DEV_1_USED
     {
         .dev      = SPI0,
         .mosi_pin = GPIO_PIN(PORT_A, 7),
-        .miso_pin = GPIO_PIN(PORT_A, 6),
+        .m iso_pin = GPIO_PIN(PORT_A, 6),
         .sclk_pin = GPIO_PIN(PORT_A, 5),
         .cs_pin   = SPI_DEV_1_CS,
         .rcumask  = RCU_APB2EN_SPI0EN_Msk,