From f7aaad842b6200d79ce769f74a4d8c3957190582 Mon Sep 17 00:00:00 2001
From: mrfaptastic <12006953+mrfaptastic@users.noreply.github.com>
Date: Sat, 20 Feb 2021 22:29:22 +0000
Subject: [PATCH] Add stopDMAtransfer function

---
 ESP32-HUB75-MatrixPanel-I2S-DMA.h | 11 ++++++++++-
 esp32_i2s_parallel_v2.c           | 16 ++++++++++++++++
 esp32_i2s_parallel_v2.h           |  1 +
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/ESP32-HUB75-MatrixPanel-I2S-DMA.h b/ESP32-HUB75-MatrixPanel-I2S-DMA.h
index 8075051..dce549e 100644
--- a/ESP32-HUB75-MatrixPanel-I2S-DMA.h
+++ b/ESP32-HUB75-MatrixPanel-I2S-DMA.h
@@ -538,6 +538,16 @@ class MatrixPanel_I2S_DMA {
      * 
      */
     const HUB75_I2S_CFG& getCfg() const {return m_cfg;};
+	
+	
+	/** 
+	 * Stop the ESP32 DMA Engine. Screen will forever be black until next ESP reboot.
+	 */
+	void stopDMAoutput() {	
+		clearScreen();
+		i2s_parallel_stop_dma(I2S_NUM_1);
+	} 
+	
 
 
   // ------- PROTECTED -------
@@ -592,7 +602,6 @@ class MatrixPanel_I2S_DMA {
     void fillRectDMA(int16_t x_coord, int16_t y_coord, int16_t w, int16_t h, uint8_t r, uint8_t g, uint8_t b);
 #endif
 
-
    // ------- PRIVATE -------
   private:
 
diff --git a/esp32_i2s_parallel_v2.c b/esp32_i2s_parallel_v2.c
index 966aaee..cb298bf 100644
--- a/esp32_i2s_parallel_v2.c
+++ b/esp32_i2s_parallel_v2.c
@@ -299,6 +299,22 @@ esp_err_t i2s_parallel_driver_install(i2s_port_t port, i2s_parallel_config_t* co
   return ESP_OK;
 }
 
+ esp_err_t i2s_parallel_stop_dma(i2s_port_t port) {
+  if(port < I2S_NUM_0 || port >= I2S_NUM_MAX) {
+    return ESP_ERR_INVALID_ARG;
+  }
+
+  i2s_dev_t* dev = I2S[port];
+  
+  // Stop all ongoing DMA operations
+  dev->out_link.stop = 1;
+  dev->out_link.start = 0;
+  dev->conf.tx_start = 0;
+  
+   return ESP_OK;
+}
+
+
  esp_err_t i2s_parallel_send_dma(i2s_port_t port, lldesc_t* dma_descriptor) {
   if(port < I2S_NUM_0 || port >= I2S_NUM_MAX) {
     return ESP_ERR_INVALID_ARG;
diff --git a/esp32_i2s_parallel_v2.h b/esp32_i2s_parallel_v2.h
index d0c6749..e344b9a 100644
--- a/esp32_i2s_parallel_v2.h
+++ b/esp32_i2s_parallel_v2.h
@@ -66,6 +66,7 @@ void link_dma_desc(volatile lldesc_t *dmadesc, volatile lldesc_t *prevdmadesc, v
 // I2S DMA Peripheral Setup Functions
 esp_err_t 	i2s_parallel_driver_install(i2s_port_t port, i2s_parallel_config_t* conf);
 esp_err_t 	i2s_parallel_send_dma(i2s_port_t port, lldesc_t* dma_descriptor);
+esp_err_t 	i2s_parallel_stop_dma(i2s_port_t port);
 i2s_dev_t* 	i2s_parallel_get_dev(i2s_port_t port);
 
 // For frame buffer flipping / double buffering