cpu/stm32: add FMC support for LCD with parallel interface

cpu/stm32/Kconfig

@@ -78,6 +78,7 @@ rsource "periph/Kconfig.fmc"
 
 if TEST_KCONFIG
 
+rsource "lcd_fmc/Kconfig"
 rsource "periph/Kconfig"
 rsource "stmclk/Kconfig"
 rsource "vectors/Kconfig"

cpu/stm32/Makefile

@@ -6,4 +6,8 @@ ifneq (,$(filter bootloader_stm32,$(USEMODULE)))
   DIRS += bootloader
 endif
 
+ifneq (,$(filter lcd_fmc,$(USEMODULE)))
+  DIRS += lcd_fmc
+endif
+
 include $(RIOTBASE)/Makefile.base

cpu/stm32/Makefile.dep

@@ -54,6 +54,10 @@ ifneq (,$(filter stm32_eth,$(USEMODULE)))
   endif
 endif
 
+ifneq (,$(filter lcd_parallel_ll_mcu,$(USEMODULE)))
+  USEMODULE += lcd_fmc
+endif
+
 ifneq (,$(filter periph_can,$(FEATURES_USED)))
   FEATURES_REQUIRED += periph_gpio
   FEATURES_REQUIRED += periph_gpio_irq

cpu/stm32/include/lcd_fmc.h

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2023 Gunar Schorcht
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @defgroup    cpu_stm32_lcd_fmc STM32 FMC/FSMC LCD low-level parallel interface driver
+ * @ingroup     cpu_stm32
+ *
+ * @{
+ */
+
+#ifndef LCD_FMC_H
+#define LCD_FMC_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Number of LCDs using FMC banks
+ *
+ * It represents the number of elements in LCD FMC bank descriptor array of
+ * type @ref lcd_fmc_desc_t. Because it is used by the preprocessor, it has
+ * to be defined as a number. It is not possible to use the @ref ARRAY_SIZE
+ * macro here.
+ *
+ * @note `LCD_FMC_NUMOF` has to be equal to the number of elements in the
+ *       LCD FMC bank descriptor array of type @ref lcd_fmc_desc_t.
+ */
+#if DOXYGEN
+#define LCD_FMC_NUMOF  1
+#endif
+
+/**
+ * @brief   Descriptor of the FMC bank used for a LCD
+ *
+ * The board definition has to specify the array @ref lcd_fmc_desc of type
+ * @ref lcd_fmc_desc_t which defines the FMC banks and the address offsets used
+ * for the LCD displays that are connected to FMC banks.
+ *
+ * @note In the case that multiple LCDs are connected to FMC banks, the FMC
+ *       bank descriptors for LCDs of type @ref lcd_fmc_desc_t
+ *       must be defined in same order as the LCD devices.
+ */
+typedef struct {
+    const fmc_bank_conf_t *bank;    /**< FMC bank config used for the LCD */
+    uint32_t cmd_offset;            /**< offset to the bank address used for commands */
+    uint32_t data_offset;           /**< offset to the bank address used for data */
+} lcd_fmc_desc_t;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LCD_FMC_H */
+/** @} */

cpu/stm32/include/periph/cpu_fmc.h

@@ -64,6 +64,17 @@
 extern "C" {
 #endif
 
+/**
+ * @brief   Gives the configuration of n-th bank
+ *
+ * This macro gives a pointer to the n-th entry of type @ref fmc_bank_conf_t of
+ * the banks configured by the board in the @ref fmc_bank_config array. n is in
+ * the range 0 ... @ref FMC_BANK_NUMOF - 1.
+ */
+#ifndef FMC_BANK_CONFIG
+#define FMC_BANK_CONFIG(n)  (&fmc_bank_config[n])
+#endif
+
 /**
  * @brief   Number of data pins used
  *

cpu/stm32/lcd_fmc/Kconfig

@@ -0,0 +1,13 @@
+# Copyright (c) 2023 Gunar Schorcht
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+#
+
+config MODULE_LCD_FMC
+    bool
+    depends on MODULE_LCD
+    select MODULE_PERIPH_FMC
+    select MODULE_PERIPH_FMC_NOR_SRAM
+    default y if HAVE_LCD_PARALLEL_LL_MCU

cpu/stm32/lcd_fmc/Makefile

@@ -0,0 +1,3 @@
+MODULE = lcd_fmc
+
+include $(RIOTBASE)/Makefile.base

cpu/stm32/lcd_fmc/lcd_fmc.c

@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2023 Gunar Schorcht
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     cpu_stm32
+ * @ingroup     drivers_periph_fmc
+ * @{
+ *
+ * @file
+ * @brief       FMC peripheral driver implementation
+ *
+ * @author      Gunar Schorcht <gunar@schorcht.net>
+ * @}
+ */
+
+#include <assert.h>
+
+#include "periph/gpio.h"
+#include "lcd.h"
+#include "lcd_internal.h"
+#include "ztimer.h"
+
+#define ENABLE_DEBUG 0
+#include "debug.h"
+
+#ifndef LCD_FMC_NUMOF
+#define LCD_FMC_NUMOF  1
+#endif
+
+#define FMC_LCD_CMD(d)  (*((__IO uint16_t *)(d->bank->address + d->cmd_offset)))
+#define FMC_LCD_DATA(d) (*((__IO uint16_t *)(d->bank->address + d->data_offset)))
+
+/* sanity check */
+static_assert(LCD_FMC_NUMOF == ARRAY_SIZE(lcd_fmc_desc),
+              "LCD_FMC_NUMOF is not equal to the number of elements in lcd_fmc_desc");
+
+#if LCD_FMC_NUMOF > 1
+/* In the case that multiple LCDs are connected to FMC banks, an array
+ * for mapping the LCD device pointer to the FMC bank descriptor is used.
+ * This requires that the FMC bank descriptors for LCDs in `lcd_fmc_desc`
+ * are defined in same order as the LCD devices. */
+static lcd_t *_lcd_fmc_desc_map[LCD_FMC_NUMOF];
+static uint8_t _lcd_index = 0;
+
+static inline uint8_t _dev_to_lcd_fmc_desc(lcd_t *dev)
+{
+    for (uint8_t i = 0; i < LCD_FMC_NUMOF; i++) {
+        if (_lcd_fmc_desc_map[i] == dev) {
+            return i;
+        }
+    }
+    assert(false);
+}
+#endif
+
+static void lcd_ll_mcu_init(lcd_t *dev)
+{
+#if LCD_FMC_NUMOF > 1
+    /* The FMC bank descriptors for LCDs in `lcd_fmc_desc` must be defined
+     * in same order as the LCD display devices. We suppose that the
+     * LCDs are initialized in that order. */
+    assert(_lcd_index < LCD_FMC_NUMOF);
+    _lcd_fmc_desc_map[_lcd_index++] = dev;
+#else
+    (void)dev;
+#endif
+}
+
+static void lcd_ll_mcu_set_data_dir(lcd_t *dev, bool output)
+{
+    /* no action needed */
+    (void)dev;
+    (void)output;
+}
+
+static void lcd_ll_mcu_cmd_start(lcd_t *dev, uint8_t cmd, bool cont)
+{
+    DEBUG("[lcd_ll_mcu] write cmd: %02x\n", cmd);
+
+    (void)cont;
+#if LCD_FMC_NUMOF > 1
+    const lcd_fmc_desc_t *desc = &lcd_fmc_desc[_dev_to_lcd_fmc_desc(dev)];
+#else
+    (void)dev;
+    const lcd_fmc_desc_t *desc = lcd_fmc_desc;
+#endif
+
+    FMC_LCD_CMD(desc) = cmd;
+    /* data synchronization barrier seems to be necessary on some STM32 MCUs. */
+    __DSB();
+}
+
+static void lcd_ll_mcu_write_byte(lcd_t *dev, bool cont, uint8_t out)
+{
+    DEBUG("[lcd_ll_mcu] write byte: %02x\n", out);
+
+    (void)cont;
+#if LCD_FMC_NUMOF > 1
+    const lcd_fmc_desc_t *desc = &lcd_fmc_desc[_dev_to_lcd_fmc_desc(dev)];
+#else
+    (void)dev;
+    const lcd_fmc_desc_t *desc = lcd_fmc_desc;
+#endif
+
+    FMC_LCD_DATA(desc) = out;
+    /* data synchronization barrier seems to be necessary on some STM32 MCUs. */
+    __DSB();
+}
+
+static uint8_t lcd_ll_mcu_read_byte(lcd_t *dev, bool cont)
+{
+    (void)cont;
+#if LCD_FMC_NUMOF > 1
+    const lcd_fmc_desc_t *desc = &lcd_fmc_desc[_dev_to_lcd_fmc_desc(dev)];
+#else
+    (void)dev;
+    const lcd_fmc_desc_t *desc = lcd_fmc_desc;
+#endif
+
+    uint8_t in = FMC_LCD_DATA(desc);
+    DEBUG("[lcd_ll_mcu] read byte: %02x\n", in);
+    return in;
+}
+
+#if IS_USED(MODULE_LCD_PARALLEL_16BIT)
+
+static void lcd_ll_mcu_write_word(lcd_t *dev, bool cont, uint16_t out)
+{
+    DEBUG("[lcd_ll_mcu] write word: %04x\n", out);
+
+    (void)cont;
+#if LCD_FMC_NUMOF > 1
+    const lcd_fmc_desc_t *desc = &lcd_fmc_desc[_dev_to_lcd_fmc_desc(dev)];
+#else
+    (void)dev;
+    const lcd_fmc_desc_t *desc = lcd_fmc_desc;
+#endif
+
+    FMC_LCD_DATA(desc) = out;
+    /* data synchronization barrier seems to be necessary on some STM32 MCUs. */
+    __DSB();
+}
+
+static uint16_t lcd_ll_mcu_read_word(lcd_t *dev, bool cont)
+{
+    (void)cont;
+#if LCD_FMC_NUMOF > 1
+    const lcd_fmc_desc_t *desc = &lcd_fmc_desc[_dev_to_lcd_fmc_desc(dev)];
+#else
+    (void)dev;
+    const lcd_fmc_desc_t *desc = lcd_fmc_desc;
+#endif
+
+    uint16_t in = FMC_LCD_DATA(desc);
+    DEBUG("[lcd_ll_mcu] read word: %04x\n", in);
+    return in;
+}
+
+#endif /* MODULE_LCD_PARALLEL_16BIT */
+
+const lcd_ll_par_driver_t lcd_ll_par_driver = {
+    .init = lcd_ll_mcu_init,
+    .set_data_dir = lcd_ll_mcu_set_data_dir,
+    .cmd_start = lcd_ll_mcu_cmd_start,
+    .write_byte = lcd_ll_mcu_write_byte,
+    .read_byte = lcd_ll_mcu_read_byte,
+#if IS_USED(MODULE_LCD_PARALLEL_16BIT)
+    .write_word = lcd_ll_mcu_write_word,
+    .read_word = lcd_ll_mcu_read_word,
+#endif
+};