drivers/spi: stm32: Use alt clock freq if available

Add support for an alternate clock. If available,
alternate clock is enabled and used to get the
device clock rate.

Fixes #41650

Signed-off-by: Erwan Gouriou <[email protected]>

Author: erwango

drivers/spi/spi_ll_stm32.c

@@ -489,10 +489,18 @@ static int spi_stm32_configure(const struct device *dev,
 #endif
 }
 
-	if (clock_control_get_rate(DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE),
-			(clock_control_subsys_t) &cfg->pclken, &clock) < 0) {
-		LOG_ERR("Failed call clock_control_get_rate");
-		return -EIO;
+	if (IS_ENABLED(STM32_SPI_OPT_CLOCK_SUPPORT) && (cfg->pclk_len > 1)) {
+		if (clock_control_get_rate(DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE),
+				(clock_control_subsys_t) &cfg->pclken[1], &clock) < 0) {
+			LOG_ERR("Failed call clock_control_get_rate(pclk[1])");
+			return -EIO;
+		}
+	} else {
+		if (clock_control_get_rate(DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE),
+				(clock_control_subsys_t) &cfg->pclken[0], &clock) < 0) {
+			LOG_ERR("Failed call clock_control_get_rate(pclk[0])");
+			return -EIO;
+		}
 	}
 
 	for (br = 1 ; br <= ARRAY_SIZE(scaler) ; ++br) {
@@ -861,11 +869,20 @@ static int spi_stm32_init(const struct device *dev)
 	int err;
 
 	if (clock_control_on(DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE),
-			       (clock_control_subsys_t) &cfg->pclken) != 0) {
+			       (clock_control_subsys_t) &cfg->pclken[0]) != 0) {
 		LOG_ERR("Could not enable SPI clock");
 		return -EIO;
 	}
 
+	if (IS_ENABLED(STM32_SPI_OPT_CLOCK_SUPPORT) && (cfg->pclk_len > 1)) {
+		if (clock_control_configure(DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE),
+					    (clock_control_subsys_t) &cfg->pclken[1],
+					    NULL) != 0) {
+			LOG_ERR("Could not select SPI soutce clock");
+			return -EIO;
+		}
+	}
+
 	if (!spi_stm32_is_subghzspi(dev)) {
 		/* Configure dt provided device signals when available */
 		err = pinctrl_apply_state(cfg->pcfg, PINCTRL_STATE_DEFAULT);
@@ -971,17 +988,20 @@ static void spi_stm32_irq_config_func_##id(const struct device *dev)		\
 #define STM32_SPI_USE_SUBGHZSPI_NSS_CONFIG(id)
 #endif
 
+
+
 #define STM32_SPI_INIT(id)						\
 STM32_SPI_IRQ_HANDLER_DECL(id);						\
 									\
 PINCTRL_DT_INST_DEFINE(id);						\
 									\
+static const struct stm32_pclken pclken_##id[] =			\
+					       STM32_DT_INST_CLOCKS(id);\
+									\
 static const struct spi_stm32_config spi_stm32_cfg_##id = {		\
 	.spi = (SPI_TypeDef *) DT_INST_REG_ADDR(id),			\
-	.pclken = {							\
-		.enr = DT_INST_CLOCKS_CELL(id, bits),			\
-		.bus = DT_INST_CLOCKS_CELL(id, bus)			\
-	},								\
+	.pclken = pclken_##id,						\
+	.pclk_len = DT_INST_NUM_CLOCKS(id),				\
 	.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(id),			\
 	STM32_SPI_IRQ_HANDLER_FUNC(id)					\
 	STM32_SPI_USE_SUBGHZSPI_NSS_CONFIG(id)				\

drivers/spi/spi_ll_stm32.h

@@ -11,8 +11,15 @@
 
 typedef void (*irq_config_func_t)(const struct device *port);
 
+/* This symbol takes the value 1 if one of the device instances */
+/* is configured in dts with an optional clock */
+#if STM32_DT_INST_DEV_OPT_CLOCK_SUPPORT
+#define STM32_SPI_OPT_CLOCK_SUPPORT 1
+#else
+#define STM32_SPI_OPT_CLOCK_SUPPORT 0
+#endif
+
 struct spi_stm32_config {
-	struct stm32_pclken pclken;
 	SPI_TypeDef *spi;
 	const struct pinctrl_dev_config *pcfg;
 #ifdef CONFIG_SPI_STM32_INTERRUPT
@@ -21,6 +28,8 @@ struct spi_stm32_config {
 #if DT_HAS_COMPAT_STATUS_OKAY(st_stm32_spi_subghz)
 	bool use_subghzspi_nss;
 #endif
+	size_t pclk_len;
+	const struct stm32_pclken *pclken;
 };
 
 #ifdef CONFIG_SPI_STM32_DMA