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-rw-r--r--drivers/led/apa102.c151
1 files changed, 151 insertions, 0 deletions
diff --git a/drivers/led/apa102.c b/drivers/led/apa102.c
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+++ b/drivers/led/apa102.c
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+/* Copyright 2020 Aldehir Rojas
+ * Copyright 2017 Mikkel (Duckle29)
+ *
+ * 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
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "apa102.h"
+#include "quantum.h"
+
+#ifndef APA102_NOPS
+# if defined(__AVR__)
+# define APA102_NOPS 0 // AVR at 16 MHz already spends 62.5 ns per clock, so no extra delay is needed
+# elif defined(PROTOCOL_CHIBIOS)
+
+# include "hal.h"
+# if defined(STM32F0XX) || defined(STM32F1XX) || defined(STM32F3XX) || defined(STM32F4XX) || defined(STM32L0XX)
+# define APA102_NOPS (100 / (1000000000L / (STM32_SYSCLK / 4))) // This calculates how many loops of 4 nops to run to delay 100 ns
+# else
+# error("APA102_NOPS configuration required")
+# define APA102_NOPS 0 // this just pleases the compile so the above error is easier to spot
+# endif
+# endif
+#endif
+
+#define io_wait \
+ do { \
+ for (int i = 0; i < APA102_NOPS; i++) { \
+ __asm__ volatile("nop\n\t" \
+ "nop\n\t" \
+ "nop\n\t" \
+ "nop\n\t"); \
+ } \
+ } while (0)
+
+#define APA102_SEND_BIT(byte, bit) \
+ do { \
+ writePin(RGB_DI_PIN, (byte >> bit) & 1); \
+ io_wait; \
+ writePinHigh(RGB_CI_PIN); \
+ io_wait; \
+ writePinLow(RGB_CI_PIN); \
+ io_wait; \
+ } while (0)
+
+uint8_t apa102_led_brightness = APA102_DEFAULT_BRIGHTNESS;
+
+void static apa102_start_frame(void);
+void static apa102_end_frame(uint16_t num_leds);
+
+void static apa102_send_frame(uint8_t red, uint8_t green, uint8_t blue, uint8_t brightness);
+void static apa102_send_byte(uint8_t byte);
+
+void apa102_setleds(LED_TYPE *start_led, uint16_t num_leds) {
+ LED_TYPE *end = start_led + num_leds;
+
+ apa102_start_frame();
+ for (LED_TYPE *led = start_led; led < end; led++) {
+ apa102_send_frame(led->r, led->g, led->b, apa102_led_brightness);
+ }
+ apa102_end_frame(num_leds);
+}
+
+// Overwrite the default rgblight_call_driver to use apa102 driver
+void rgblight_call_driver(LED_TYPE *start_led, uint8_t num_leds) { apa102_setleds(start_led, num_leds); }
+
+void static apa102_init(void) {
+ setPinOutput(RGB_DI_PIN);
+ setPinOutput(RGB_CI_PIN);
+
+ writePinLow(RGB_DI_PIN);
+ writePinLow(RGB_CI_PIN);
+}
+
+void apa102_set_brightness(uint8_t brightness) {
+ if (brightness > APA102_MAX_BRIGHTNESS) {
+ apa102_led_brightness = APA102_MAX_BRIGHTNESS;
+ } else if (brightness < 0) {
+ apa102_led_brightness = 0;
+ } else {
+ apa102_led_brightness = brightness;
+ }
+}
+
+void static apa102_send_frame(uint8_t red, uint8_t green, uint8_t blue, uint8_t brightness) {
+ apa102_send_byte(0b11100000 | brightness);
+ apa102_send_byte(blue);
+ apa102_send_byte(green);
+ apa102_send_byte(red);
+}
+
+void static apa102_start_frame(void) {
+ apa102_init();
+ for (uint16_t i = 0; i < 4; i++) {
+ apa102_send_byte(0);
+ }
+}
+
+void static apa102_end_frame(uint16_t num_leds) {
+ // This function has been taken from: https://github.com/pololu/apa102-arduino/blob/master/APA102.h
+ // and adapted. The code is MIT licensed. I think thats compatible?
+ //
+ // The data stream seen by the last LED in the chain will be delayed by
+ // (count - 1) clock edges, because each LED before it inverts the clock
+ // line and delays the data by one clock edge. Therefore, to make sure
+ // the last LED actually receives the data we wrote, the number of extra
+ // edges we send at the end of the frame must be at least (count - 1).
+ //
+ // Assuming we only want to send these edges in groups of size K, the
+ // C/C++ expression for the minimum number of groups to send is:
+ //
+ // ((count - 1) + (K - 1)) / K
+ //
+ // The C/C++ expression above is just (count - 1) divided by K,
+ // rounded up to the nearest whole number if there is a remainder.
+ //
+ // We set K to 16 and use the formula above as the number of frame-end
+ // bytes to transfer. Each byte has 16 clock edges.
+ //
+ // We are ignoring the specification for the end frame in the APA102
+ // datasheet, which says to send 0xFF four times, because it does not work
+ // when you have 66 LEDs or more, and also it results in unwanted white
+ // pixels if you try to update fewer LEDs than are on your LED strip.
+ uint16_t iterations = (num_leds + 14) / 16;
+ for (uint16_t i = 0; i < iterations; i++) {
+ apa102_send_byte(0);
+ }
+
+ apa102_init();
+}
+
+void static apa102_send_byte(uint8_t byte) {
+ APA102_SEND_BIT(byte, 7);
+ APA102_SEND_BIT(byte, 6);
+ APA102_SEND_BIT(byte, 5);
+ APA102_SEND_BIT(byte, 4);
+ APA102_SEND_BIT(byte, 3);
+ APA102_SEND_BIT(byte, 2);
+ APA102_SEND_BIT(byte, 1);
+ APA102_SEND_BIT(byte, 0);
+}