Remove all MAX7456 specific code, replace it with generic interfaces

- Rename max7456_symbols.h to osd_symbols.h. We'll expect all supported
OSD drivers to use the same font style.
- Introduce drivers/osd.h, which defines the supported video systems
and the format for the OSD characters that all drivers must support.
- Remove drivers/vcd.h, since having a file for a single enum is
kind of annoying, move this enum to the new drivers/osd.h file.
- Add osdGetDisplayPort() for retriving the display port used by
the OSD.
- Add a new display function named writeFontCharacter() which takes
a character address and its data.
- Use the aforementioned 2 functions to implement character font
uploading in fc_msp.c, so it's not MAX7456-specific anymore.

Author: fiam

src/main/drivers/display.c

@@ -229,6 +229,14 @@ bool displayGetFontMetadata(displayFontMetadata_t *metadata, const displayPort_t
     return false;
 }
 
+int displayWriteFontCharacter(displayPort_t *instance, uint16_t addr, const osdCharacter_t *chr)
+{
+    if (instance->vTable->writeFontCharacter) {
+        return instance->vTable->writeFontCharacter(instance, addr, chr);
+    }
+    return -1;
+}
+
 void displayInit(displayPort_t *instance, const displayPortVTable_t *vTable)
 {
     instance->vTable = vTable;

src/main/drivers/display.h

@@ -22,6 +22,8 @@
 
 #include "config/parameter_group.h"
 
+typedef struct osdCharacter_s osdCharacter_t;
+
 typedef struct displayConfig_s {
     bool force_sw_blink; // Enable SW blinking. Used for chips which don't work correctly with HW blink.
 } displayConfig_t;
@@ -91,6 +93,7 @@ typedef struct displayPortVTable_s {
     uint32_t (*txBytesFree)(const displayPort_t *displayPort);
     textAttributes_t (*supportedTextAttributes)(const displayPort_t *displayPort);
     bool (*getFontMetadata)(displayFontMetadata_t *metadata, const displayPort_t *displayPort);
+    int (*writeFontCharacter)(displayPort_t *instance, uint16_t addr, const osdCharacter_t *chr);
 } displayPortVTable_t;
 
 typedef struct displayPortProfile_s {
@@ -119,4 +122,5 @@ void displayHeartbeat(displayPort_t *instance);
 void displayResync(displayPort_t *instance);
 uint16_t displayTxBytesFree(const displayPort_t *instance);
 bool displayGetFontMetadata(displayFontMetadata_t *metadata, const displayPort_t *instance);
+int displayWriteFontCharacter(displayPort_t *instance, uint16_t addr, const osdCharacter_t *chr);
 void displayInit(displayPort_t *instance, const displayPortVTable_t *vTable);

src/main/drivers/max7456.c

@@ -29,15 +29,13 @@
 #include "common/utils.h"
 
 #include "drivers/bus.h"
-#include "drivers/light_led.h"
+#include "drivers/dma.h"
 #include "drivers/io.h"
-#include "drivers/time.h"
+#include "drivers/light_led.h"
 #include "drivers/nvic.h"
-#include "drivers/dma.h"
-#include "drivers/vcd.h"
+#include "drivers/time.h"
 
 #include "max7456.h"
-#include "max7456_symbols.h"
 
 // VM0 bits
 #define VIDEO_BUFFER_DISABLE        0x01
@@ -637,7 +635,7 @@ void max7456RefreshAll(void)
     }
 }
 
-void max7456ReadNvm(uint16_t char_address, max7456Character_t *chr)
+void max7456ReadNvm(uint16_t char_address, osdCharacter_t *chr)
 {
     // Check if device is available
     if (state.dev == NULL) {
@@ -669,7 +667,7 @@ void max7456ReadNvm(uint16_t char_address, max7456Character_t *chr)
     max7456Unlock();
 }
 
-void max7456WriteNvm(uint16_t char_address, const max7456Character_t *chr)
+void max7456WriteNvm(uint16_t char_address, const osdCharacter_t *chr)
 {
     uint8_t spiBuff[(sizeof(chr->data) * 2 + 2) * 2];
     int bufPtr = 0;

src/main/drivers/max7456.h

@@ -18,7 +18,8 @@
 #pragma once
 
 #include <stdbool.h>
-#include "drivers/vcd.h"
+
+#include "drivers/osd.h"
 
 #ifndef WHITEBRIGHTNESS
   #define WHITEBRIGHTNESS 0x01
@@ -41,14 +42,10 @@ enum VIDEO_TYPES { AUTO = 0, PAL, NTSC };
 #define MAX7456_MODE_BLINK    (1 << 4)
 #define MAX7456_MODE_SOLID_BG (1 << 5)
 
-typedef struct max7456Character_s {
-    uint8_t data[54];
-} max7456Character_t;
-
 void max7456Init(const videoSystem_e videoSystem);
 void max7456Update(void);
-void max7456ReadNvm(uint16_t char_address, max7456Character_t *chr);
-void max7456WriteNvm(uint16_t char_address, const max7456Character_t *chr);
+void max7456ReadNvm(uint16_t char_address, osdCharacter_t *chr);
+void max7456WriteNvm(uint16_t char_address, const osdCharacter_t *chr);
 uint16_t max7456GetScreenSize(void);
 uint8_t max7456GetRowsCount(void);
 void max7456Write(uint8_t x, uint8_t y, const char *buff, uint8_t mode);

src/main/drivers/osd.h

@@ -0,0 +1,56 @@
+/*
+ * This file is part of Cleanflight, Betaflight and INAV
+ *
+ * Cleanflight, Betaflight and INAV are free software. You can
+ * redistribute this software and/or modify this software under
+ * the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License,
+ * or (at your option) any later version.
+ *
+ * Cleanflight, Betaflight and INAV are distributed in the hope that
+ * they will be useful, but WITHOUT ANY WARRANTY; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software.
+ *
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+#define OSD_CHAR_WIDTH 12
+#define OSD_CHAR_HEIGHT 18
+#define OSD_CHAR_BITS_PER_PIXEL 2
+#define OSD_CHAR_BYTES (OSD_CHAR_WIDTH * OSD_CHAR_HEIGHT * OSD_CHAR_BITS_PER_PIXEL / 8)
+
+#define OSD_CHARACTER_COLOR_BLACK 0
+#define OSD_CHARACTER_COLOR_TRANSPARENT 1
+#define OSD_CHARACTER_COLOR_WHITE 2
+
+// 3 is unused but it's interpreted as transparent by all drivers
+
+
+// Video Character Display parameters
+
+typedef enum {
+    VIDEO_SYSTEM_AUTO = 0,
+    VIDEO_SYSTEM_PAL,
+    VIDEO_SYSTEM_NTSC
+} videoSystem_e;
+
+typedef enum {
+    OSD_DRIVER_NONE = 0,
+    OSD_DRIVER_MAX7456 = 1,
+} osdDriver_e;
+
+// osdCharacter_t represents the binary data for an OSD
+// character. All OSD drivers use the same character format
+// as defined by OSD_CHARACTER_WIDTH, OSD_CHARACTER_HEIGHT
+// and OSD_CHARACTER_BITS_PER_PIXEL.
+typedef struct osdCharacter_s {
+    uint8_t data[OSD_CHAR_BYTES];
+} osdCharacter_t;

src/main/drivers/max7456_symbols.h src/main/drivers/osd_symbols.hsrc/main/drivers/max7456_symbols.h renamed to src/main/drivers/osd_symbols.h

@@ -1,5 +1,5 @@
-/* @file max7456_symbols.h
- * @brief max7456 symbols for the mwosd font set
+/* @file osd_symbols.h
+ * @brief Based on max7456 symbols for the mwosd font set
  *
  * @author Nathan Tsoi [email protected]
  *
@@ -21,7 +21,7 @@
 
 #pragma once
 
-#ifdef USE_MAX7456
+#ifdef USE_OSD
 
 #define SYM_RSSI                  0x01 // 001 Icon RSSI
 #define SYM_AH_LEFT               0x02 // 002 Arrow left
@@ -53,8 +53,8 @@
 #define SYM_HEADING_S             0x19 // 025 Heading Graphic south
 #define SYM_HEADING_E             0x1A // 026 Heading Graphic east
 #define SYM_HEADING_W             0x1B // 027 Heading Graphic west
-#define SYM_HEADING_DIVIDED_LINE  0x1C // 028 Heading Graphic 
-#define SYM_HEADING_LINE          0x1D // 029 Heading Graphic 
+#define SYM_HEADING_DIVIDED_LINE  0x1C // 028 Heading Graphic
+#define SYM_HEADING_LINE          0x1D // 029 Heading Graphic
 
 #define SYM_SAT_L                 0x1E // 030 Sats left
 #define SYM_SAT_R                 0x1F // 031 Sats right
@@ -124,13 +124,13 @@
 #define SYM_BATT_FULL             0x90 // 144 Battery full
 #define SYM_BATT_5                0x91 // 145 Battery
 #define SYM_BATT_4                0x92 // 146 Battery
-#define SYM_BATT_3                0x93 // 147 Battery 
+#define SYM_BATT_3                0x93 // 147 Battery
 #define SYM_BATT_2                0x94 // 148 Battery
 #define SYM_BATT_1                0x95 // 149 Battery
 #define SYM_BATT_EMPTY            0x96 // 150 Battery empty
 
 #define SYM_AIR                   0x97 // 151 Air speed
-//                                0x98 // 152 Home point map                                   
+//                                0x98 // 152 Home point map
 #define SYM_FTS                   0x99 // 153 FT/S
 #define SYM_AMP                   0x9A // 154 A
 #define SYM_ON_M                  0x9B // 155 On MN
@@ -187,9 +187,9 @@
 #define SYM_ZERO_HALF_LEADING_DOT 0xD0 // 208 to 217 Numbers with leading dot
 
 #define SYM_AH_CH_AIRCRAFT0       0xDA // 218 Crossair aircraft left
-#define SYM_AH_CH_AIRCRAFT1       0xDB // 219 Crossair aircraft 
+#define SYM_AH_CH_AIRCRAFT1       0xDB // 219 Crossair aircraft
 #define SYM_AH_CH_AIRCRAFT2       0xDC // 220 Crossair aircraft center
-#define SYM_AH_CH_AIRCRAFT3       0xDD // 221 Crossair aircraft 
+#define SYM_AH_CH_AIRCRAFT3       0xDD // 221 Crossair aircraft
 #define SYM_AH_CH_AIRCRAFT4       0xDE // 222 Crossair aircraft right
 
 #define SYM_PITCH_DOWN            0xDF // 223 Pitch down

src/main/drivers/vcd.h

@@ -56,7 +56,7 @@ extern uint8_t __config_end;
 #include "drivers/io.h"
 #include "drivers/io_impl.h"
 #include "drivers/logging.h"
-#include "drivers/max7456_symbols.h"
+#include "drivers/osd_symbols.h"
 #include "drivers/rx_pwm.h"
 #include "drivers/sdcard.h"
 #include "drivers/sensor.h"

src/main/fc/cli.c

@@ -54,6 +54,7 @@
 #include "drivers/light_led.h"
 #include "drivers/logging.h"
 #include "drivers/nvic.h"
+#include "drivers/osd.h"
 #include "drivers/pwm_esc_detect.h"
 #include "drivers/pwm_mapping.h"
 #include "drivers/pwm_output.h"
@@ -70,7 +71,6 @@
 #include "drivers/time.h"
 #include "drivers/timer.h"
 #include "drivers/uart_inverter.h"
-#include "drivers/vcd.h"
 #include "drivers/io.h"
 #include "drivers/exti.h"
 #include "drivers/io_pca9685.h"

src/main/fc/fc_init.c

@@ -41,8 +41,9 @@
 #include "drivers/accgyro/accgyro.h"
 #include "drivers/bus_i2c.h"
 #include "drivers/compass/compass.h"
-#include "drivers/max7456.h"
-#include "drivers/max7456_symbols.h"
+#include "drivers/display.h"
+#include "drivers/osd.h"
+#include "drivers/osd_symbols.h"
 #include "drivers/pwm_mapping.h"
 #include "drivers/sdcard.h"
 #include "drivers/serial.h"
@@ -315,7 +316,7 @@ static bool mspFcProcessOutCommand(uint16_t cmdMSP, sbuf_t *dst, mspPostProcessF
         // 0 = no OSD
         // 1 = OSD slave (not supported in INAV)
         // 2 = OSD chip on board
-#if defined(USE_OSD) && defined(USE_MAX7456)
+#if defined(USE_OSD)
         sbufWriteU8(dst, 2);
 #else
         sbufWriteU8(dst, 0);
@@ -1020,13 +1021,9 @@ static bool mspFcProcessOutCommand(uint16_t cmdMSP, sbuf_t *dst, mspPostProcessF
 
     case MSP_OSD_CONFIG:
 #ifdef USE_OSD
-        sbufWriteU8(dst, 1); // OSD supported
+        sbufWriteU8(dst, OSD_DRIVER_MAX7456); // OSD supported
         // send video system (AUTO/PAL/NTSC)
-#ifdef USE_MAX7456
         sbufWriteU8(dst, osdConfig()->video_system);
-#else
-        sbufWriteU8(dst, 0);
-#endif
         sbufWriteU8(dst, osdConfig()->units);
         sbufWriteU8(dst, osdConfig()->rssi_alarm);
         sbufWriteU16(dst, currentBatteryProfile->capacity.warning);
@@ -1038,7 +1035,7 @@ static bool mspFcProcessOutCommand(uint16_t cmdMSP, sbuf_t *dst, mspPostProcessF
             sbufWriteU16(dst, osdConfig()->item_pos[0][i]);
         }
 #else
-        sbufWriteU8(dst, 0); // OSD not supported
+        sbufWriteU8(dst, OSD_DRIVER_NONE); // OSD not supported
 #endif
         break;
 
@@ -2234,11 +2231,7 @@ static mspResult_e mspFcProcessInCommand(uint16_t cmdMSP, sbuf_t *src)
         // set all the other settings
         if ((int8_t)tmp_u8 == -1) {
             if (dataSize >= 10) {
-#ifdef USE_MAX7456
                 osdConfigMutable()->video_system = sbufReadU8(src);
-#else
-                sbufReadU8(src); // Skip video system
-#endif
                 osdConfigMutable()->units = sbufReadU8(src);
                 osdConfigMutable()->rssi_alarm = sbufReadU8(src);
                 currentBatteryProfileMutable->capacity.warning = sbufReadU16(src);
@@ -2264,23 +2257,26 @@ static mspResult_e mspFcProcessInCommand(uint16_t cmdMSP, sbuf_t *src)
         break;
 
     case MSP_OSD_CHAR_WRITE:
-#ifdef USE_MAX7456
         if (dataSize >= 55) {
-            max7456Character_t chr;
+            osdCharacter_t chr;
             uint16_t addr;
             if (dataSize >= 56) {
+                // 16 bit character address
                 addr = sbufReadU16(src);
             } else {
+                // 8 bit character address, for backwards compatibility
                 addr = sbufReadU8(src);
             }
             for (unsigned ii = 0; ii < sizeof(chr.data); ii++) {
                 chr.data[ii] = sbufReadU8(src);
             }
-            // !!TODO - replace this with a device independent implementation
-            max7456WriteNvm(addr, &chr);
-        } else
+            displayPort_t *osdDisplayPort = osdGetDisplayPort();
+            if (osdDisplayPort) {
+                displayWriteFontCharacter(osdDisplayPort, addr, &chr);
+            }
+        } else {
             return MSP_RESULT_ERROR;
-#endif // USE_MAX7456
+        }
         break;
 #endif // USE_OSD