boards/stm32f746g-disco: enable LTDC peripheral

boards/stm32f746g-disco/Kconfig

@@ -16,6 +16,7 @@ config BOARD_STM32F746G_DISCO
     select HAS_PERIPH_DMA
     select HAS_PERIPH_ETH
     select HAS_PERIPH_I2C
+    select HAS_PERIPH_LTDC
     select HAS_PERIPH_RTC
     select HAS_PERIPH_RTT
     select HAS_PERIPH_SPI

boards/stm32f746g-disco/Makefile.features

@@ -5,6 +5,7 @@ CPU_MODEL = stm32f746ng
 FEATURES_PROVIDED += periph_dma
 FEATURES_PROVIDED += periph_eth
 FEATURES_PROVIDED += periph_i2c
+FEATURES_PROVIDED += periph_ltdc
 FEATURES_PROVIDED += periph_rtc
 FEATURES_PROVIDED += periph_rtt
 FEATURES_PROVIDED += periph_spi

boards/stm32f746g-disco/board.c

@@ -18,9 +18,19 @@
  * @}
  */
 
+#include "kernel_defines.h"
 #include "board.h"
 #include "periph/gpio.h"
 
 void board_init(void)
 {
+    gpio_init(BACKLIGHT_PIN, GPIO_OUT);
+    if (IS_USED(MODULE_PERIPH_LTDC)) {
+        gpio_init(LCD_DISP_PIN, GPIO_OUT);
+        gpio_set(LCD_DISP_PIN);
+        gpio_set(BACKLIGHT_PIN);
+    }
+    else {
+        gpio_clear(BACKLIGHT_PIN);
+    }
 }

boards/stm32f746g-disco/doc.txt

@@ -27,7 +27,7 @@ Current hardware support:
 | Ethernet | X |  |
 | USB OTG FS | X |  |
 | USB OTG HS | - |  |
-| TFT LCD | - |  |
+| TFT LCD | X |  |
 | Capacitive touch screen | - | |
 | User microphones | - | |
 | External Quad-SPI Flash | - | |

boards/stm32f746g-disco/include/board.h

@@ -27,6 +27,36 @@
 extern "C" {
 #endif
 
+/**
+ * @name    LCD Backlight control defines
+ * @{
+ */
+#define BACKLIGHT_PIN       GPIO_PIN(PORT_K, 3)     /**< Backlight pin */
+#define BACKLIGHT_MASK      (1 << 3)                /**< Backlight pin mask */
+
+/** Set the backlight pin */
+#define BACKLIGHT_ON        (GPIOK->BSRR = BACKLIGHT_MASK)
+/** Clear the backlight pin */
+#define BACKLIGHT_OFF       (GPIOK->BSRR = (BACKLIGHT_MASK << 16))
+/** Toggle the backlight pin */
+#define BACKLIGHT_TOGGLE    (GPIOK->ODR  ^= BACKLIGHT_MASK)
+/** @} */
+
+/**
+ * @name    LCD display enable pin
+ * @{
+ */
+#define LCD_DISP_PIN        GPIO_PIN(PORT_I, 12)    /**< LCD screen enable pin */
+/** @} */
+
+/**
+ * @name    LCD screen dimensions
+ * @{
+ */
+#define LCD_SCREEN_WIDTH        480     /**< LCD screen width */
+#define LCD_SCREEN_HEIGHT       272     /**< LCD screen height */
+/** @} */
+
 /**
  * @name User button
  * @{

boards/stm32f746g-disco/include/periph_conf.h

@@ -173,6 +173,62 @@ static const eth_conf_t eth_config = {
 #define ETH_DMA_ISR        isr_dma2_stream0
 /** @} */
 
+/**
+ * @name LTDC configuration
+ * @{
+ */
+/** LTDC static configuration struct */
+static const ltdc_conf_t ltdc_config = {
+    .bus        = APB2,
+    .rcc_mask   = RCC_APB2ENR_LTDCEN,
+    .clk_pin    = { .pin = GPIO_PIN(PORT_I, 14), .af = GPIO_AF14, },
+    .de_pin     = { .pin = GPIO_PIN(PORT_K, 7), .af = GPIO_AF14, },
+    .hsync_pin  = { .pin = GPIO_PIN(PORT_I, 10), .af = GPIO_AF14, },
+    .vsync_pin  = { .pin = GPIO_PIN(PORT_I, 9), .af = GPIO_AF14, },
+    .r_pin      = {
+        { .pin = GPIO_PIN(PORT_I, 15), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 0), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 1), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 2), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 3), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 4), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 5), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 6), .af = GPIO_AF14, },
+    },
+    .g_pin      = {
+        { .pin = GPIO_PIN(PORT_J, 7), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 8), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 9), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 10), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 11), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_K, 0), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_K, 1), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_K, 2), .af = GPIO_AF14, },
+    },
+    .b_pin      = {
+        { .pin = GPIO_PIN(PORT_E, 4), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 13), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 14), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_J, 15), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_G, 12), .af = GPIO_AF9, },
+        { .pin = GPIO_PIN(PORT_K, 4), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_K, 5), .af = GPIO_AF14, },
+        { .pin = GPIO_PIN(PORT_K, 6), .af = GPIO_AF14, },
+    },
+    /* values below come from STM32CubeF7 code and differ from the typical
+     * values mentioned in the RK043FN48H datasheet. Both sets of values work
+     * with the display.
+     * See the discussion in https://community.st.com/s/question/0D50X0000BOvdWP/how-to-set-displays-parameters-
+     */
+    .hsync      = 41,
+    .vsync      = 10,
+    .hbp        = 13,
+    .hfp        = 32,
+    .vbp        = 2,
+    .vfp        = 2,
+};
+/** @} */
+
 #ifdef __cplusplus
 }
 #endif