From c6b7a0d386c347f20117943831a0215659d37c47 Mon Sep 17 00:00:00 2001
From: Nick Brassel <nick@tzarc.org>
Date: Thu, 16 Jul 2020 16:39:49 +1000
Subject: [PATCH] Add support for DMAMUX-capable MCU configuration with WS2812
 PWM driver. (#9471)

---
 docs/ws2812_driver.md        | 3 ++-
 drivers/chibios/ws2812_pwm.c | 8 ++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/docs/ws2812_driver.md b/docs/ws2812_driver.md
index 941e1bde08..c1b96329e9 100644
--- a/docs/ws2812_driver.md
+++ b/docs/ws2812_driver.md
@@ -92,6 +92,7 @@ Configure the hardware via your config.h:
 #define WS2812_PWM_PAL_MODE 2  // Pin "alternate function", see the respective datasheet for the appropriate values for your MCU. default: 2
 #define WS2812_DMA_STREAM STM32_DMA1_STREAM2  // DMA Stream for TIMx_UP, see the respective reference manual for the appropriate values for your MCU.
 #define WS2812_DMA_CHANNEL 2  // DMA Channel for TIMx_UP, see the respective reference manual for the appropriate values for your MCU.
+#define WS2812_DMAMUX_ID STM32_DMAMUX1_TIM2_UP // DMAMUX configuration for TIMx_UP -- only required if your MCU has a DMAMUX peripheral, see the respective reference manual for the appropriate values for your MCU.
 ```
 
 You must also turn on the PWM feature in your halconf.h and mcuconf.h
@@ -117,5 +118,5 @@ Note: This only applies to STM32 boards.
 
  To configure the `RGB_DI_PIN` to open drain configuration add this to your config.h file: 
 ```c
- #define WS2812_EXTERNAL_PULLUP 
+#define WS2812_EXTERNAL_PULLUP
 ```
diff --git a/drivers/chibios/ws2812_pwm.c b/drivers/chibios/ws2812_pwm.c
index 7113db11e0..d93fa24735 100644
--- a/drivers/chibios/ws2812_pwm.c
+++ b/drivers/chibios/ws2812_pwm.c
@@ -23,6 +23,9 @@
 #ifndef WS2812_DMA_CHANNEL
 #    define WS2812_DMA_CHANNEL 2  // DMA Channel for TIMx_UP
 #endif
+#if (STM32_DMA_SUPPORTS_DMAMUX == TRUE) && !defined(WS2812_DMAMUX_ID)
+#    error "please consult your MCU's datasheet and specify in your config.h: #define WS2812_DMAMUX_ID STM32_DMAMUX1_TIM?_UP"
+#endif
 
 // Push Pull or Open Drain Configuration
 // Default Push Pull
@@ -184,6 +187,11 @@ void ws2812_init(void) {
     dmaStreamSetMode(WS2812_DMA_STREAM, STM32_DMA_CR_CHSEL(WS2812_DMA_CHANNEL) | STM32_DMA_CR_DIR_M2P | STM32_DMA_CR_PSIZE_WORD | STM32_DMA_CR_MSIZE_WORD | STM32_DMA_CR_MINC | STM32_DMA_CR_CIRC | STM32_DMA_CR_PL(3));
     // M2P: Memory 2 Periph; PL: Priority Level
 
+#if (STM32_DMA_SUPPORTS_DMAMUX == TRUE)
+    // If the MCU has a DMAMUX we need to assign the correct resource
+    dmaSetRequestSource(WS2812_DMA_STREAM, WS2812_DMAMUX_ID);
+#endif
+
     // Start DMA
     dmaStreamEnable(WS2812_DMA_STREAM);