Merge pull request #9948 from fiam/agh_max7456_delayed_init

MAX7456: Support delayed initialization

src/main/drivers/max7456.c

@@ -450,7 +450,7 @@ void max7456PreInit(const max7456Config_t *max7456Config)
 // Here we init only CS and try to init MAX for first time.
 // Also detect device type (MAX v.s. AT)
 
-bool max7456Init(const max7456Config_t *max7456Config, const vcdProfile_t *pVcdProfile, bool cpuOverclock)
+max7456InitStatus_e max7456Init(const max7456Config_t *max7456Config, const vcdProfile_t *pVcdProfile, bool cpuOverclock)
 {
     max7456DeviceDetected = false;
 
@@ -462,13 +462,13 @@ bool max7456Init(const max7456Config_t *max7456Config, const vcdProfile_t *pVcdP
     max7456HardwareReset();
 
     if (!max7456Config->csTag || !max7456Config->spiDevice) {
-        return false;
+        return MAX7456_INIT_NOT_CONFIGURED;
     }
 
     busdev->busdev_u.spi.csnPin = IOGetByTag(max7456Config->csTag);
 
     if (!IOIsFreeOrPreinit(busdev->busdev_u.spi.csnPin)) {
-        return false;
+        return MAX7456_INIT_NOT_CONFIGURED;
     }
 
     IOInit(busdev->busdev_u.spi.csnPin, OWNER_OSD_CS, 0);
@@ -492,7 +492,7 @@ bool max7456Init(const max7456Config_t *max7456Config, const vcdProfile_t *pVcdP
 
     if (osdm != 0x1B) {
         IOConfigGPIO(busdev->busdev_u.spi.csnPin, IOCFG_IPU);
-        return false;
+        return MAX7456_INIT_NOT_FOUND;
     }
 
     // At this point, we can claim the ownership of the CS pin
@@ -560,7 +560,7 @@ bool max7456Init(const max7456Config_t *max7456Config, const vcdProfile_t *pVcdP
 #endif
 
     // Real init will be made later when driver detect idle.
-    return true;
+    return MAX7456_INIT_OK;
 }
 
 /**

src/main/drivers/max7456.h

@@ -20,6 +20,8 @@
 
 #pragma once
 
+#include <stdint.h>
+
 #include "drivers/display.h"
 
 /** PAL or NTSC, value is number of chars total */
@@ -28,12 +30,23 @@
 #define VIDEO_LINES_NTSC          13
 #define VIDEO_LINES_PAL           16
 
+typedef enum {
+    // IO defined and MAX7456 was detected
+    MAX7456_INIT_OK = 0,
+    // IO defined, but MAX7456 could not be detected (maybe not yet
+    // powered on)
+    MAX7456_INIT_NOT_FOUND = -1,
+    // No MAX7456 IO defined, which means either the we don't have it or
+    // it's not properly configured
+    MAX7456_INIT_NOT_CONFIGURED = -2,
+} max7456InitStatus_e;
+
 extern uint16_t maxScreenSize;
 struct vcdProfile_s;
 void    max7456HardwareReset(void);
 struct max7456Config_s;
 void    max7456PreInit(const struct max7456Config_s *max7456Config);
-bool    max7456Init(const struct max7456Config_s *max7456Config, const struct vcdProfile_s *vcdProfile, bool cpuOverclock);
+max7456InitStatus_e max7456Init(const struct max7456Config_s *max7456Config, const struct vcdProfile_s *vcdProfile, bool cpuOverclock);
 void    max7456Invert(bool invert);
 void    max7456Brightness(uint8_t black, uint8_t white);
 void    max7456DrawScreen(void);

src/main/io/displayport_max7456.c

@@ -168,7 +168,15 @@ static bool isReady(displayPort_t *instance)
 {
     UNUSED(instance);
 
-    return max7456IsDeviceDetected();
+    if (!max7456IsDeviceDetected()) {
+        // Try to initialize the device
+        if (max7456Init(max7456Config(), vcdProfile(), systemConfig()->cpu_overclock) != MAX7456_INIT_OK) {
+            return false;
+        }
+        // At this point the device has been initialized and detected
+        resync(&max7456DisplayPort);
+    }
+    return true;
 }
 
 static const displayPortVTable_t max7456VTable = {
@@ -193,15 +201,24 @@ static const displayPortVTable_t max7456VTable = {
 
 displayPort_t *max7456DisplayPortInit(const vcdProfile_t *vcdProfile)
 {
-    if (
-        !max7456Init(max7456Config(), vcdProfile, systemConfig()->cpu_overclock)
-    ) {
+    switch (max7456Init(max7456Config(), vcdProfile, systemConfig()->cpu_overclock)) {
+    case MAX7456_INIT_NOT_FOUND:
+        // MAX7456 IO pins are defined, but we could not get a reply
+        // from it at this time. Delay full initialization to
+        // isReady()
+        displayInit(&max7456DisplayPort, &max7456VTable);
+        break;
+    case MAX7456_INIT_OK:
+        // MAX7456 configured and detected
+        displayInit(&max7456DisplayPort, &max7456VTable);
+        resync(&max7456DisplayPort);
+        break;
+    case MAX7456_INIT_NOT_CONFIGURED:
+        // MAX7456 IO pins are not defined. We either don't have
+        // it on board or either the configuration for it has
+        // not been set.
         return NULL;
     }
-
-    displayInit(&max7456DisplayPort, &max7456VTable);
-
-    resync(&max7456DisplayPort);
     return &max7456DisplayPort;
 }
 #endif // USE_MAX7456