allow for different GPIO pins to drive multiple led stripes with one SPI

lib/ledspitask/GwLedSpiTask.cpp

@@ -105,6 +105,9 @@ static size_t ledsToBuffer(int numLeds,const Color *leds,uint8_t *buffer){
     return p-buffer;
 }
 
+/**
+ * prepare a GPIO pin to be used as the data line for an led stripe
+*/
 bool prepareGpio(GwLog *logger, uint8_t pin){
     esp_err_t err=gpio_set_direction((gpio_num_t)pin,GPIO_MODE_OUTPUT);
     if (err != ESP_OK){
@@ -118,6 +121,106 @@ bool prepareGpio(GwLog *logger, uint8_t pin){
     }
     return true;
 }
+/**
+ * initialize the SPI bus and add a device for the LED output
+ * it still does not attach any PINs to the bus
+ * this will be done later when sending out
+ * this way we can use one hardware SPI for multiple led stripes
+ * @param bus : the SPI bus
+ * @param device: <out> the device handle being filled
+ * @return false on error
+*/
+bool prepareSpi(GwLog *logger,spi_host_device_t bus,spi_device_handle_t *device){
+    spi_bus_config_t buscfg = {
+        .mosi_io_num = -1,
+        .miso_io_num = -1,
+        .sclk_io_num = -1,
+        .quadwp_io_num = -1,
+        .quadhd_io_num = -1,
+        .max_transfer_sz = 0,
+        .flags=SPICOMMON_BUSFLAG_GPIO_PINS
+        };   
+    esp_err_t err=spi_bus_initialize(bus,&buscfg,SPI_DMA_CH_AUTO);    
+    if (err != ESP_OK){
+        LOG_DEBUG(GwLog::ERROR,"unable to initialize SPI bus %d,mosi=%d, error=%d",
+        (int)bus,-1,(int)err);
+        return false;
+    }
+    spi_device_interface_config_t devcfg = {
+        .command_bits = 0,
+        .address_bits = 0,
+        .dummy_bits = 0,
+        .mode = 0,
+        .duty_cycle_pos = 128,
+        .cs_ena_pretrans = 0,
+        .cs_ena_posttrans =0,
+        .clock_speed_hz = 2500000, //2.5 Mhz 
+        .input_delay_ns =0,
+        .spics_io_num = -1,             //CS pin
+        .queue_size = 1 //see https://github.com/espressif/esp-idf/issues/9450
+        };
+    err=spi_bus_add_device(bus,&devcfg,device);
+    if (err != ESP_OK){
+        LOG_DEBUG(GwLog::ERROR,"unable to add device to SPI bus %d,mosi=%d, error=%d",
+        (int)bus,-1,(int)err);
+        return false;
+    }
+    return true;
+}
+
+/**
+ * send out a set of Color values to a connected led stripe
+ * this method will block until sen dis complete
+ * But as the transfer is using DMA the CPU is not busy during the wait time
+ * @param pin: the IO pin to be used. Will be attached to the SPI device before and deattached after 
+ * @param numLeds: the number of Color values
+ * @param leds: pointer to the first Color value
+ * @param bus: the SPI bus
+ * @param device: the SPI device handle
+ **/
+bool sendToLeds(GwLog *logger, uint8_t pin, int numLeds, Color *leds, spi_host_device_t bus, spi_device_handle_t &device, uint8_t *buffer = NULL)
+{
+    bool ownsBuffer = false;
+    size_t bufferSize = numLeds * 3 * 3;
+    if (buffer == NULL)
+    {
+        ownsBuffer = true;
+        buffer = (uint8_t *)heap_caps_malloc(bufferSize, MALLOC_CAP_DMA);
+        if (!buffer)
+        {
+            LOG_DEBUG(GwLog::ERROR, "unable to allocate %d bytes of DMA buffer", (int)bufferSize);
+            return false;
+        }
+    }
+    bool rv = true;
+    ledsToBuffer(numLeds, leds, buffer);
+    struct spi_transaction_t ta = {
+        .flags = 0,
+        .cmd = 0,
+        .addr = 0,
+        .length = bufferSize * 8,
+        .rxlength = 0,
+        .tx_buffer = buffer};
+    int64_t now = esp_timer_get_time();
+    esp_rom_gpio_connect_out_signal(pin, spi_periph_signal[bus].spid_out, false, false);
+    esp_err_t ret = spi_device_transmit(device, &ta);
+    esp_rom_gpio_connect_out_signal(pin, SIG_GPIO_OUT_IDX, false, false);
+    int64_t end = esp_timer_get_time();
+    if (ret != ESP_OK)
+    {
+        LOG_DEBUG(GwLog::ERROR, "unable to send led data: %d", (int)ret);
+        rv = false;
+    }
+    else
+    {
+        LOG_DEBUG(GwLog::DEBUG, "successfully send led data for %d leds, %lld us", numLeds, end - now);
+    }
+    if (ownsBuffer)
+    {
+        heap_caps_free(buffer);
+    }
+    return rv;
+}
 
 #define EXIT_TASK delay(50);vTaskDelete(NULL);return;
 void handleSpiLeds(GwApi *api){
@@ -150,53 +253,22 @@ void handleSpiLeds(GwApi *api){
         EXIT_TASK;
     }
     LOG_DEBUG(GwLog::ERROR,"SpiLed task started");
-    uint8_t ledPin=GWLED_PIN;
-    spi_bus_config_t buscfg = {
-        .mosi_io_num = -1,
-        .miso_io_num = -1,
-        .sclk_io_num = -1,
-        .quadwp_io_num = -1,
-        .quadhd_io_num = -1,
-        .max_transfer_sz = 0,
-        .flags=SPICOMMON_BUSFLAG_GPIO_PINS
-        };   
-    esp_err_t err=spi_bus_initialize(bus,&buscfg,SPI_DMA_CH_AUTO);    
-    if (err != ESP_OK){
-        LOG_DEBUG(GwLog::ERROR,"unable to initialize SPI bus %d,mosi=%d, error=%d",
-        (int)bus,ledPin,(int)err);
+
+    if (! prepareGpio(logger,GWLED_PIN)){
         EXIT_TASK;
     }
-    spi_device_interface_config_t devcfg = {
-        .command_bits = 0,
-        .address_bits = 0,
-        .dummy_bits = 0,
-        .mode = 0,
-        .duty_cycle_pos = 128,
-        .cs_ena_pretrans = 0,
-        .cs_ena_posttrans =0,
-        .clock_speed_hz = 2500000, //2.5 Mhz 
-        .input_delay_ns =0,
-        .spics_io_num = -1,             //CS pin
-        .queue_size = 1 //see https://github.com/espressif/esp-idf/issues/9450
-        };
-    spi_device_handle_t device;
-    err=spi_bus_add_device(bus,&devcfg,&device);
-    if (err != ESP_OK){
-        LOG_DEBUG(GwLog::ERROR,"unable to add device to SPI bus %d,mosi=%d, error=%d",
-        (int)bus,ledPin,(int)err);
+    #ifdef GWLED_PIN2
+        if (! prepareGpio(logger,GWLED_PIN2)){
         EXIT_TASK;
     }
-    if (! prepareGpio(logger,ledPin)){
+    #endif
+    spi_device_handle_t device;
+    if (! prepareSpi(logger,bus,&device)){
         EXIT_TASK;
     }
     const int NUMLEDS=2;
     Color leds[NUMLEDS];
-    size_t bufferSize=NUMLEDS*3*3;
-    uint8_t *outbuffer=(uint8_t*) heap_caps_malloc(bufferSize,MALLOC_CAP_DMA);
-    if (! outbuffer){
-        LOG_DEBUG(GwLog::ERROR,"unable to allocate %d bytes of DMA buffer",(int)bufferSize);
-        EXIT_TASK;
-    }
+
     uint8_t brightness=api->getConfig()->getInt(GwConfigDefinitions::ledBrightness,128);
     GwLedMode currentMode=LED_GREEN;
     bool first=true;
@@ -205,6 +277,10 @@ void handleSpiLeds(GwApi *api){
     int seccount=0;
     int modeIndex=0;
     GwLedMode modes[4]={LED_WHITE,LED_GREEN,LED_RED,LED_BLUE};
+    /*
+    currently there is somple simple testcode in the loop
+    that changes colors every 5s
+    */
     while (true)
     {
         delay(50);
@@ -216,6 +292,11 @@ void handleSpiLeds(GwApi *api){
         }
         GwLedMode newMode = currentMode;
         /*
+        by using the task API you can easily build a safe communication between
+        another task and this one
+        So the other task could set the colors and this task would just output them
+        */
+        /*
         IButtonTask buttonState = api->taskInterfaces()->get<IButtonTask>(apiResult);
         if (apiResult >= 0 )
         {
@@ -249,27 +330,24 @@ void handleSpiLeds(GwApi *api){
             first=false;
             leds[0] = setBrightness(colorFromMode(newMode),brightness);
             leds[1] = leds[0];
+            //swap g and r for led1 to see differences
+            uint8_t t=leds[1].g;
+            leds[1].g=leds[1].r;
+            leds[1].r=t;
             LOG_DEBUG(GwLog::DEBUG,"(%d) mode=%d,setting color g=%d,r=%d,b=%d",modeIndex,(int)newMode,leds[0].g,leds[0].r,leds[0].b);
-            ledsToBuffer(NUMLEDS,leds,outbuffer);
-            struct spi_transaction_t ta = {
-                .flags = 0,
-                .cmd = 0,
-                .addr = 0,
-                .length = bufferSize*8,
-                .rxlength = 0,
-                .tx_buffer = outbuffer
-                };
-            int64_t now=esp_timer_get_time();
-            esp_rom_gpio_connect_out_signal(ledPin,spi_periph_signal[bus].spid_out,false,false);
-            esp_err_t ret = spi_device_transmit(device, &ta);
-            esp_rom_gpio_connect_out_signal(ledPin,SIG_GPIO_OUT_IDX,false,false);
-            int64_t end=esp_timer_get_time();
-            if (ret != ESP_OK){
-                LOG_DEBUG(GwLog::ERROR,"unable to send led data: %d",(int)ret);
-            }
-            else{
-                LOG_DEBUG(GwLog::DEBUG,"successfully send led data for %d leds, %lld us",NUMLEDS,end-now);
-            }
+            /**
+             * by defining GWLED_PIN2 you can control 2 different stripes on different GPIOs
+             * in this example it would be just 1 led on each
+             * if GWLED_PIN2 is not defined both leds are assumed to be connected to one GPIO
+             * the second LED will always have r<->g swapped to see that they are working independently
+            */
+            #ifdef GWLED_PIN2
+            //send the 2 leds separately to different gpios
+            sendToLeds(logger,GWLED_PIN,1,leds,bus,device);
+            sendToLeds(logger,GWLED_PIN2,1,&leds[1],bus,device);
+            #else
+            sendToLeds(logger,GWLED_PIN,NUMLEDS,leds,bus,device);
+            #endif
             currentMode = newMode;
         }
     }

lib/ledspitask/GwLedSpiTask.h

@@ -4,5 +4,5 @@
 //task function
 void handleSpiLeds(GwApi *param);
 
-DECLARE_USERTASK(handleSpiLeds);
+DECLARE_USERTASK_PARAM(handleSpiLeds,4000);
 #endif

lib/ledspitask/platformio.ini

@@ -10,6 +10,7 @@ build_flags =
 	-D BOARD_HOMBERGER
     -D GWLED_SPI=1
     -D GWLED_PIN=33
+    -D GWLED_PIN2=32
 	${env.build_flags}
 upload_port = /dev/esp32
 upload_protocol = esptool