1 files changed, 151 insertions, 0 deletions

diff --git a/drivers/led/apa102.c b/drivers/led/apa102.c
new file mode 100644
index 000000000..7396dc3c5
--- /dev/null
+++ b/drivers/led/apa102.c
@@ -0,0 +1,151 @@
+/* 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);
+}