drivers: display: stm32_ltdc: Add SMH attribute for LTDC buffer.

The LTDC driver was using the video buffer SMH attribute.

Signed-off-by: Ibrahim Abdalkader <i.abdalkader@gmail.com>

Author: iabdalkader

drivers/display/Kconfig.stm32_ltdc

@@ -56,6 +56,17 @@ config STM32_LTDC_FB_NUM
 config STM32_LTDC_FB_USE_SHARED_MULTI_HEAP
 	bool "Use shared multi heap for the display buffer"
 
+config STM32_LTDC_FB_SMH_ATTRIBUTE
+	int "Shared multi heap attribute for the display buffer"
+	depends on STM32_LTDC_FB_USE_SHARED_MULTI_HEAP
+	default 0
+	range 0 2
+	help
+	  Shared multi heap attribute for the display buffer:
+	  0: SMH_REG_ATTR_CACHEABLE
+	  1: SMH_REG_ATTR_NON_CACHEABLE
+	  2: SMH_REG_ATTR_EXTERNAL
+
 config STM32_LTDC_DISABLE_FMC_BANK1
 	bool "Disable FMC bank1 for STM32F7/H7 series"
 	depends on SOC_SERIES_STM32H7X || SOC_SERIES_STM32F7X

drivers/display/display_stm32_ltdc.c

@@ -419,7 +419,7 @@ static int stm32_ltdc_init(const struct device *dev)
 
 #if defined(CONFIG_STM32_LTDC_FB_USE_SHARED_MULTI_HEAP)
 	data->frame_buffer = shared_multi_heap_aligned_alloc(
-			CONFIG_VIDEO_BUFFER_SMH_ATTRIBUTE,
+			CONFIG_STM32_LTDC_FB_SMH_ATTRIBUTE,
 			32,
 			CONFIG_STM32_LTDC_FB_NUM * data->frame_buffer_len);