Fix incorrect delay when setting WS2812 (and similar) leds (#9302)

* Fix incorrect delay when setting WS2812 (and similar) leds

* Add documentation for WS2812_DELAY_MICROSECONDS

* Remove improper cast to uint8_t

Co-authored-by: Sergey Vlasov <sigprof@gmail.com>

* Remove unneeded cast to uint8_t and correct math

Co-authored-by: Sergey Vlasov <sigprof@gmail.com>

* microseconds -> µs

Co-authored-by: Ryan <fauxpark@gmail.com>

* Make documentation better match the spec sheet.

Co-authored-by: Ryan <fauxpark@gmail.com>

* Rename macro to match spec sheet

* Further correction to the delay maths for the SPI case.

Co-authored-by: Joel Challis <git@zvecr.com>

* Move ws2812_common.h to the drivers directory

* Revert "Further correction to the delay maths for the SPI case."

This reverts commit e61b56a2cfc7dfec9992a7a3af92afa50e5b8ec0.

* Remove ws2812_setleds_pin(); consolidate ws2812.h

Co-authored-by: Sergey Vlasov <sigprof@gmail.com>
Co-authored-by: Ryan <fauxpark@gmail.com>
Co-authored-by: Joel Challis <git@zvecr.com>

docs/ws2812_driver.md

@@ -19,6 +19,15 @@ These LEDs are called "addressable" because instead of using a wire per color, e
 
 ## Driver configuration
 
+### All drivers
+
+Different versions of the addressable LEDs have differing requirements for the T<sub>RST</sub> period between frames.
+The default setting is 280 µs, which should work for most cases, but this can be overridden in your config.h. e.g.:
+
+```c
+#define WS2812_TRST_US 80
+```
+
 ### Bitbang
 Default driver, the absence of configuration assumes this driver. To configure it, add this to your rules.mk:
 

drivers/avr/ws2812.c

@@ -36,25 +36,15 @@
 
 static inline void ws2812_sendarray_mask(uint8_t *data, uint16_t datlen, uint8_t masklo, uint8_t maskhi);
 
-// Setleds for standard RGB
-void inline ws2812_setleds(LED_TYPE *ledarray, uint16_t number_of_leds) {
-    // wrap up usage of RGB_DI_PIN
-    ws2812_setleds_pin(ledarray, number_of_leds, RGB_DI_PIN);
-}
-
-void ws2812_setleds_pin(LED_TYPE *ledarray, uint16_t number_of_leds, uint8_t pin) {
-    DDRx_ADDRESS(RGB_DI_PIN) |= pinmask(pin);
+void ws2812_setleds(LED_TYPE *ledarray, uint16_t number_of_leds) {
+    DDRx_ADDRESS(RGB_DI_PIN) |= pinmask(RGB_DI_PIN);
 
-    uint8_t masklo = ~(pinmask(pin)) & PORTx_ADDRESS(pin);
-    uint8_t maskhi = pinmask(pin) | PORTx_ADDRESS(pin);
+    uint8_t masklo = ~(pinmask(RGB_DI_PIN)) & PORTx_ADDRESS(RGB_DI_PIN);
+    uint8_t maskhi = pinmask(RGB_DI_PIN) | PORTx_ADDRESS(RGB_DI_PIN);
 
     ws2812_sendarray_mask((uint8_t *)ledarray, number_of_leds * sizeof(LED_TYPE), masklo, maskhi);
 
-#ifdef RGBW
-    _delay_us(80);
-#else
-    _delay_us(50);
-#endif
+    _delay_us(WS2812_TRST_US);
 }
 
 /*

drivers/chibios/ws2812.c

@@ -51,7 +51,7 @@
 
 // The reset gap can be 6000 ns, but depending on the LED strip it may have to be increased
 // to values like 600000 ns. If it is too small, the pixels will show nothing most of the time.
-#define RES 10000  // Width of the low gap between bits to cause a frame to latch
+#define RES (1000 * WS2812_TRST_US) // Width of the low gap between bits to cause a frame to latch
 
 void sendByte(uint8_t byte) {
     // WS2812 protocol wants most significant bits first

drivers/chibios/ws2812.h

@@ -1,16 +0,0 @@
-#pragma once
-
-#include "quantum/color.h"
-
-/* User Interface
- *
- * Input:
- *         ledarray:           An array of GRB data describing the LED colors
- *         number_of_leds:     The number of LEDs to write
- *
- * The functions will perform the following actions:
- *         - Set the data-out pin as output
- *         - Send out the LED data
- *         - Wait 50us to reset the LEDs
- */
-void ws2812_setleds(LED_TYPE *ledarray, uint16_t number_of_leds);

drivers/chibios/ws2812_pwm.c

@@ -53,11 +53,10 @@
 /**
  * @brief   Number of bit-periods to hold the data line low at the end of a frame
  *
- * The reset period for each frame must be at least 50 uS; so we add in 50 bit-times
- * of zeroes at the end. (50 bits)*(1.25 uS/bit) = 62.5 uS, which gives us some
- * slack in the timing requirements
+ * The reset period for each frame is defined in WS2812_TRST_US.
+ * Calculate the number of zeroes to add at the end assuming 1.25 uS/bit:
  */
-#define WS2812_RESET_BIT_N (50)
+#define WS2812_RESET_BIT_N (1000 * WS2812_TRST_US / 1250)
 #define WS2812_COLOR_BIT_N (RGBLED_NUM * 24)                   /**< Number of data bits */
 #define WS2812_BIT_N (WS2812_COLOR_BIT_N + WS2812_RESET_BIT_N) /**< Total number of bits in a frame */
 

drivers/chibios/ws2812_spi.c

@@ -36,7 +36,7 @@
 #define NB_COLORS 3
 #define BYTES_FOR_LED (BYTES_FOR_LED_BYTE * NB_COLORS)
 #define DATA_SIZE (BYTES_FOR_LED * RGBLED_NUM)
-#define RESET_SIZE 200
+#define RESET_SIZE (1000 * WS2812_TRST_US / (2 * 1250))
 #define PREAMBLE_SIZE 4
 
 static uint8_t txbuf[PREAMBLE_SIZE + DATA_SIZE + RESET_SIZE] = {0};

drivers/avr/ws2812.h → drivers/ws2812.h

@@ -1,11 +1,4 @@
 /*
- * light weight WS2812 lib include
- *
- * Version 2.3  - Nev 29th 2015
- * Author: Tim (cpldcpu@gmail.com)
- *
- * Please do not change this file! All configuration is handled in "ws2812_config.h"
- *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 2 of the License, or
@@ -24,12 +17,20 @@
 
 #include "quantum/color.h"
 
+/*
+ * Older WS2812s can handle a reset time (TRST) of 50us, but recent 
+ * component revisions require a minimum of 280us.
+ */
+
+#if !defined(WS2812_TRST_US)
+#define WS2812_TRST_US 280
+#endif
+
 /* User Interface
  *
  * Input:
  *         ledarray:           An array of GRB data describing the LED colors
  *         number_of_leds:     The number of LEDs to write
- *         pin (optional):     A pin_t definition for the line to drive
  *
  * The functions will perform the following actions:
  *         - Set the data-out pin as output
@@ -37,4 +38,3 @@
  *         - Wait 50us to reset the LEDs
  */
 void ws2812_setleds(LED_TYPE *ledarray, uint16_t number_of_leds);
-void ws2812_setleds_pin(LED_TYPE *ledarray, uint16_t number_of_leds, uint8_t pin);

keyboards/wilba_tech/wt_rgb_backlight.c

@@ -55,7 +55,7 @@
 #endif
 
 #if defined(RGB_BACKLIGHT_DAWN60)
-#include "drivers/avr/ws2812.h"
+#include "ws2812.h"
 LED_TYPE g_ws2812_leds[WS2812_LED_TOTAL];
 #endif