[stm32wb, spi] Initial SPI implementation

AlexLanzano · AlexLanzano · commit ab80d13f7b81 · 2026-02-15T21:51:28.000-05:00
diff --git a/examples/stm32wb/stm32wb55xx_nucleo.c b/examples/stm32wb/stm32wb55xx_nucleo.c
@@ -30,9 +30,13 @@ whal_Gpio g_whalGpio = {
 
     .cfg = &(whal_Stm32wbGpio_Cfg) {
         .clkCtrl = &g_whalClock,
-        .clk = &(whal_Stm32wbRcc_Clk) {WHAL_STM32WB55_GPIOB_CLOCK},
+        .clk = (const void *[2]) {
+            &(whal_Stm32wbRcc_Clk){WHAL_STM32WB55_GPIOA_CLOCK},
+            &(whal_Stm32wbRcc_Clk){WHAL_STM32WB55_GPIOB_CLOCK},
+        },
+        .clkCount = 2,
 
-        .pinCfg = (whal_Stm32wbGpio_PinCfg[3]) {
+        .pinCfg = (whal_Stm32wbGpio_PinCfg[7]) {
             [LED_PIN] = { /* LED */
                 .port = WHAL_STM32WB_GPIO_PORT_B,
                 .pin = 5,
@@ -60,8 +64,44 @@ whal_Gpio g_whalGpio = {
                 .pull = WHAL_STM32WB_GPIO_PULL_UP,
                 .altFn = 7,
             },
+            [SPI1_SCK_PIN] = { /* SPI1 SCK */
+                .port = WHAL_STM32WB_GPIO_PORT_A,
+                .pin = 5,
+                .mode = WHAL_STM32WB_GPIO_MODE_ALTFN,
+                .outType = WHAL_STM32WB_GPIO_OUTTYPE_PUSHPULL,
+                .speed = WHAL_STM32WB_GPIO_SPEED_FAST,
+                .pull = WHAL_STM32WB_GPIO_PULL_UP,
+                .altFn = 5,
+            },
+            [SPI1_MISO_PIN] = { /* SPI1 MISO */
+                .port = WHAL_STM32WB_GPIO_PORT_A,
+                .pin = 6,
+                .mode = WHAL_STM32WB_GPIO_MODE_ALTFN,
+                .outType = WHAL_STM32WB_GPIO_OUTTYPE_PUSHPULL,
+                .speed = WHAL_STM32WB_GPIO_SPEED_FAST,
+                .pull = WHAL_STM32WB_GPIO_PULL_UP,
+                .altFn = 5,
+            },
+            [SPI1_MOSI_PIN] = { /* SPI1 MOSI */
+                .port = WHAL_STM32WB_GPIO_PORT_A,
+                .pin = 7,
+                .mode = WHAL_STM32WB_GPIO_MODE_ALTFN,
+                .outType = WHAL_STM32WB_GPIO_OUTTYPE_PUSHPULL,
+                .speed = WHAL_STM32WB_GPIO_SPEED_FAST,
+                .pull = WHAL_STM32WB_GPIO_PULL_UP,
+                .altFn = 5,
+            },
+            [CS_PIN] = { /* SPI1 CS */
+                .port = WHAL_STM32WB_GPIO_PORT_A,
+                .pin = 4,
+                .mode = WHAL_STM32WB_GPIO_MODE_OUT,
+                .outType = WHAL_STM32WB_GPIO_OUTTYPE_PUSHPULL,
+                .speed = WHAL_STM32WB_GPIO_SPEED_LOW,
+                .pull = WHAL_STM32WB_GPIO_PULL_UP,
+                .altFn = 0,
+            },
         },
-        .pinCount = 3,
+        .pinCount = 7,
     },
 };
 
@@ -97,3 +137,12 @@ whal_Flash g_whalFlash = {
         .size = 0x100000,
     },
 };
+
+whal_Spi g_whalSpi = {
+    WHAL_STM32WB55_SPI1_DEVICE,
+
+    .cfg = &(whal_Stm32wbSpi_Cfg) {
+        .clkCtrl = &g_whalClock,
+        .clk = &(whal_Stm32wbRcc_Clk) {WHAL_STM32WB55_SPI1_CLOCK},
+    },
+};
diff --git a/examples/stm32wb/stm32wb55xx_nucleo.h b/examples/stm32wb/stm32wb55xx_nucleo.h
@@ -13,6 +13,10 @@ enum {
     LED_PIN,
     LPUART1_TX_PIN,
     LPUART1_RX_PIN,
+    SPI1_SCK_PIN,
+    SPI1_MISO_PIN,
+    SPI1_MOSI_PIN,
+    CS_PIN,
 };
 
 /* RCC clock controller instance. */
@@ -30,5 +34,7 @@ extern whal_Uart g_whalUart;
 /* Flash controller instance. */
 extern whal_Flash g_whalFlash;
 
+/* SPI controller instance. */
+extern whal_Spi g_whalSpi;
 
 #endif /* STM32WB55XX_NUCLEO_H */
diff --git a/src/gpio/stm32wb_gpio.c b/src/gpio/stm32wb_gpio.c
@@ -109,10 +109,12 @@ whal_Error whal_Stm32wbGpio_Init(whal_Gpio *gpioDev)
     cfg = (whal_Stm32wbGpio_Cfg *)gpioDev->cfg;
     pinCfg = cfg->pinCfg;
 
-    /* Enable GPIO port clock before accessing registers */
-    err = whal_Clock_Enable(cfg->clkCtrl, cfg->clk);
-    if (err) {
-        return err;
+    for (size_t i = 0; i < cfg->clkCount; ++i) {
+        /* Enable GPIO port clock before accessing registers */
+        err = whal_Clock_Enable(cfg->clkCtrl, cfg->clk[i]);
+        if (err) {
+            return err;
+        }
     }
 
     /* Initialize each pin in the configuration array */
@@ -130,12 +132,15 @@ whal_Error whal_Stm32wbGpio_Deinit(whal_Gpio *gpioDev)
 {
     whal_Error err;
     whal_Stm32wbGpio_Cfg *cfg;
+
     cfg = (whal_Stm32wbGpio_Cfg *)gpioDev->cfg;
 
-    /* Disable GPIO port clock */
-    err = whal_Clock_Disable(cfg->clkCtrl, cfg->clk);
-    if (err) {
-        return err;
+    for (size_t i = 0; i < cfg->clkCount; ++i) {
+        /* Disable GPIO port clock */
+        err = whal_Clock_Disable(cfg->clkCtrl, cfg->clk[i]);
+        if (err) {
+            return err;
+        }
     }
 
     return WHAL_SUCCESS;
diff --git a/src/spi/stm32wb_spi.c b/src/spi/stm32wb_spi.c
@@ -1,56 +1,205 @@
 #include <stdint.h>
 #include <wolfHAL/spi/stm32wb_spi.h>
 #include <wolfHAL/spi/spi.h>
+#include <wolfHAL/clock/clock.h>
 #include <wolfHAL/error.h>
+#include <wolfHAL/regmap.h>
+#include <wolfHAL/bitops.h>
 
 /*
- * STM32WB SPI Driver - Stub Implementation
+ * STM32WB SPI Register Definitions
  *
- * TODO: Implement SPI register configuration and data transfer.
+ * The SPI peripheral provides full-duplex synchronous serial communication.
+ * This driver configures it in master mode with software slave management
+ * and 8-bit data frames.
  */
 
+/* Control Register 1 - master config, clock, enable */
+#define SSPI_CR1_REG  0x00
+#define SSPI_CR1_CPHA WHAL_MASK(0)           /* Clock phase */
+#define SSPI_CR1_CPOL WHAL_MASK(1)           /* Clock polarity */
+#define SSPI_CR1_MSTR WHAL_MASK(2)           /* Master selection */
+#define SSPI_CR1_BR   WHAL_MASK_RANGE(5, 3)  /* Baud rate prescaler */
+#define SSPI_CR1_SPE  WHAL_MASK(6)           /* SPI enable */
+#define SSPI_CR1_SSI  WHAL_MASK(8)           /* Internal slave select */
+#define SSPI_CR1_SSM  WHAL_MASK(9)           /* Software slave management */
+
+/* Control Register 2 - data size, FIFO threshold */
+#define SSPI_CR2_REG   0x04
+#define SSPI_CR2_DS    WHAL_MASK_RANGE(11, 8) /* Data size (0111 = 8-bit) */
+#define SSPI_CR2_FRXTH WHAL_MASK(12)          /* FIFO reception threshold */
+
+/* Status Register */
+#define SSPI_SR_REG  0x08
+#define SSPI_SR_RXNE WHAL_MASK(0) /* Receive buffer not empty */
+#define SSPI_SR_TXE  WHAL_MASK(1) /* Transmit buffer empty */
+#define SSPI_SR_BSY  WHAL_MASK(7) /* Busy flag */
+
+/* Data Register - 8/16-bit access */
+#define SSPI_DR_REG  0x0C
+#define SSPI_DR_MASK WHAL_MASK_RANGE(7, 0)
+
+/* 8-bit data size value for DS field */
+#define SSPI_DS_8BIT 0x7
+
+/*
+ * Calculate the baud rate prescaler index for a target baud rate.
+ *
+ * SPI baud rate = fPCLK / (2 ^ (BR + 1))
+ *   BR=0 -> /2,  BR=1 -> /4,  BR=2 -> /8, ... BR=7 -> /256
+ *
+ * Returns the smallest prescaler that does not exceed the target baud.
+ */
+static uint32_t whal_Stm32wbSpi_CalcBr(size_t pclk, uint32_t targetBaud)
+{
+    uint32_t br;
+
+    for (br = 0; br < 7; br++) {
+        if ((pclk / (2u << br)) <= targetBaud) {
+            return br;
+        }
+    }
+
+    return 7;
+}
+
+/*
+ * Configure SPI mode and baud rate, then enable the peripheral.
+ * Must be called with SPE disabled.
+ */
+static void whal_Stm32wbSpi_ApplyComCfg(const whal_Regmap *reg,
+                                        whal_Stm32wbSpi_Cfg *cfg,
+                                        whal_Stm32wbSpi_ComCfg *comCfg)
+{
+    size_t pclk;
+    uint32_t cpol, cpha, br;
+
+    whal_Clock_GetRate(cfg->clkCtrl, &pclk);
+
+    br = whal_Stm32wbSpi_CalcBr(pclk, comCfg->baud);
+
+    cpol = (comCfg->mode >> 1) & 1;
+    cpha = comCfg->mode & 1;
+
+    /* Disable SPE before reconfiguring */
+    whal_Reg_Update(reg->base, SSPI_CR1_REG, SSPI_CR1_SPE,
+                    whal_SetBits(SSPI_CR1_SPE, 0));
+
+    /* Set mode and baud rate */
+    whal_Reg_Update(reg->base, SSPI_CR1_REG,
+                    SSPI_CR1_CPOL | SSPI_CR1_CPHA | SSPI_CR1_BR,
+                    whal_SetBits(SSPI_CR1_CPOL, cpol) |
+                    whal_SetBits(SSPI_CR1_CPHA, cpha) |
+                    whal_SetBits(SSPI_CR1_BR, br));
+
+    /* Re-enable SPE */
+    whal_Reg_Update(reg->base, SSPI_CR1_REG, SSPI_CR1_SPE,
+                    whal_SetBits(SSPI_CR1_SPE, 1));
+}
+
 whal_Error whal_Stm32wbSpi_Init(whal_Spi *spiDev)
 {
-    (void)spiDev;
+    whal_Error err;
+    whal_Stm32wbSpi_Cfg *cfg;
+    const whal_Regmap *reg = &spiDev->regmap;
+
+    cfg = (whal_Stm32wbSpi_Cfg *)spiDev->cfg;
+
+    err = whal_Clock_Enable(cfg->clkCtrl, cfg->clk);
+    if (err != WHAL_SUCCESS) {
+        return err;
+    }
+
+    /* Master mode with software slave management */
+    whal_Reg_Update(reg->base, SSPI_CR1_REG,
+                    SSPI_CR1_MSTR | SSPI_CR1_SSM | SSPI_CR1_SSI,
+                    whal_SetBits(SSPI_CR1_MSTR, 1) |
+                    whal_SetBits(SSPI_CR1_SSM, 1) |
+                    whal_SetBits(SSPI_CR1_SSI, 1));
+
+    /* 8-bit data size and FIFO receive threshold for 8-bit */
+    whal_Reg_Update(reg->base, SSPI_CR2_REG,
+                    SSPI_CR2_DS | SSPI_CR2_FRXTH,
+                    whal_SetBits(SSPI_CR2_DS, SSPI_DS_8BIT) |
+                    whal_SetBits(SSPI_CR2_FRXTH, 1));
+
     return WHAL_SUCCESS;
 }
 
 whal_Error whal_Stm32wbSpi_Deinit(whal_Spi *spiDev)
 {
-    (void)spiDev;
+    whal_Error err;
+    const whal_Regmap *reg = &spiDev->regmap;
+    whal_Stm32wbSpi_Cfg *cfg = (whal_Stm32wbSpi_Cfg *)spiDev->cfg;
+
+    /* Disable SPI */
+    whal_Reg_Update(reg->base, SSPI_CR1_REG, SSPI_CR1_SPE,
+                    whal_SetBits(SSPI_CR1_SPE, 0));
+
+    err = whal_Clock_Disable(cfg->clkCtrl, cfg->clk);
+    if (err) {
+        return err;
+    }
+
     return WHAL_SUCCESS;
 }
 
 whal_Error whal_Stm32wbSpi_SendRecv(whal_Spi *spiDev, void *spiComCfg, const uint8_t *tx,
                                     size_t txLen, uint8_t *rx, size_t rxLen)
 {
-    (void)spiDev;
-    (void)spiComCfg;
-    (void)tx;
-    (void)txLen;
-    (void)rx;
-    (void)rxLen;
+    const whal_Regmap *reg = &spiDev->regmap;
+    whal_Stm32wbSpi_Cfg *cfg = (whal_Stm32wbSpi_Cfg *)spiDev->cfg;
+    whal_Stm32wbSpi_ComCfg *comCfg = (whal_Stm32wbSpi_ComCfg *)spiComCfg;
+    size_t totalLen = txLen > rxLen ? txLen : rxLen;
+    size_t status;
+    size_t d;
+
+    whal_Stm32wbSpi_ApplyComCfg(reg, cfg, comCfg);
+
+    for (size_t i = 0; i < totalLen; i++) {
+        if (txLen) {
+            /* Wait for TX buffer empty */
+            do {
+                whal_Reg_Get(reg->base, SSPI_SR_REG, SSPI_SR_TXE, &status);
+            } while (!status);
+
+            /* Write data or dummy byte */
+            uint8_t txByte = (i >= txLen) ? tx[txLen-1] : tx[i];
+            *(volatile uint8_t *)(reg->base + SSPI_DR_REG) = txByte;
+        }
+
+        if (rxLen) {
+            /* Wait for RX buffer not empty */
+            do {
+                whal_Reg_Get(reg->base, SSPI_SR_REG, SSPI_SR_RXNE, &status);
+            } while (!status);
+
+            /* Read received byte */
+            d = *(volatile uint8_t *)(reg->base + SSPI_DR_REG);
+            if (i < rxLen) {
+                rx[i] = (uint8_t)d;
+            }
+        }
+    }
+
+    /* Wait for not busy */
+    do {
+        whal_Reg_Get(reg->base, SSPI_SR_REG, SSPI_SR_BSY, &status);
+    } while (status);
+
     return WHAL_SUCCESS;
 }
 
 whal_Error whal_Stm32wbSpi_Send(whal_Spi *spiDev, void *spiComCfg, const uint8_t *data,
                                 size_t dataSz)
 {
-    (void)spiDev;
-    (void)spiComCfg;
-    (void)data;
-    (void)dataSz;
-    return WHAL_SUCCESS;
+    return whal_Stm32wbSpi_SendRecv(spiDev, spiComCfg, data, dataSz, NULL, 0);
 }
 
 whal_Error whal_Stm32wbSpi_Recv(whal_Spi *spiDev, void *spiComCfg, uint8_t *data,
                                 size_t dataSz)
 {
-    (void)spiDev;
-    (void)spiComCfg;
-    (void)data;
-    (void)dataSz;
-    return WHAL_SUCCESS;
+    return whal_Stm32wbSpi_SendRecv(spiDev, spiComCfg, NULL, 0, data, dataSz);
 }
 
 const whal_SpiDriver whal_Stm32wbSpi_Driver = {
diff --git a/wolfHAL/gpio/stm32wb_gpio.h b/wolfHAL/gpio/stm32wb_gpio.h
@@ -104,7 +104,8 @@ typedef struct {
  */
 typedef struct {
     whal_Clock *clkCtrl; /* Clock controller for enabling GPIO clock */
-    void *clk;           /* Clock descriptor (whal_Stm32wbRcc_Clk) */
+    const void **clk;    /* Array of clock descriptors */
+    size_t clkCount;     /* Number of clock descriptors */
 
     whal_Stm32wbGpio_PinCfg *pinCfg; /* Array of pin configurations */
     size_t pinCount;                  /* Number of pins to configure */
diff --git a/wolfHAL/platform/st/stm32wb55xx.h b/wolfHAL/platform/st/stm32wb55xx.h
@@ -6,6 +6,7 @@
 #include <wolfHAL/clock/stm32wb_rcc.h>
 #include <wolfHAL/gpio/stm32wb_gpio.h>
 #include <wolfHAL/uart/stm32wb_uart.h>
+#include <wolfHAL/spi/stm32wb_spi.h>
 #include <wolfHAL/flash/stm32wb_flash.h>
 
 /*
@@ -87,4 +88,8 @@
     .regOffset = 0x60,              \
     .enableMask = (1 << 14)
 
+#define WHAL_STM32WB55_SPI1_CLOCK   \
+    .regOffset = 0x60,              \
+    .enableMask = (1 << 12)
+
 #endif /* WHAL_STM32WB55XX_H */
diff --git a/wolfHAL/spi/stm32wb_spi.h b/wolfHAL/spi/stm32wb_spi.h
