Rewrite APA102 support (#10894)

* Rewrite APA102 support

The APA102 source was broken by commit 16a15c1cfcbfd0feb2c2cf1383676747e2f97d73 as it did not include the
quantum header. This commit addresses that, as well as other issues with
transferring bytes over the SPI interface, i.e. it was not setting the
clock pin back to low after sending a bit.

The deviation when sending the end frame is kept, but updated to the
latest from the referenced project.

Finally, these changes expose the global LED brightness parameter
of the APA102. Brightness values are configurable through
`APA102_DEFAULT_BRIGHTNESS` and `APA102_MAX_BRIGHTNESS`.

* Fix typo in led brightness extern

* Move driver out of AVR directory and add delay for ARM

* Experimental APA102 support on AVR and ARM

Co-authored-by: Alde Rojas <hello@alde.io>

* Refactor apa102_send_byte() calls to a loop

* Implement io_wait function for ARM

* Move APA102 drivers to own directory, fix copyright notice

* Add APA102 keymap to handwired/onekey

* Simplify RGBLIGHT_ENABLE/DRIVER option handling

Co-authored-by: Mikkel Jeppesen <2756925+Duckle29@users.noreply.github.com>

2 files changed, 192 insertions, 0 deletions

diff --git a/drivers/apa102/apa102.c b/drivers/apa102/apa102.c
new file mode 100644
index 0000000000..7396dc3c55
--- /dev/null
+++ b/drivers/apa102/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);
+}
diff --git a/drivers/apa102/apa102.h b/drivers/apa102/apa102.h
new file mode 100644
index 0000000000..58cf020c1e
--- /dev/null
+++ b/drivers/apa102/apa102.h
@@ -0,0 +1,41 @@
+/* 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/>.
+ */
+
+#pragma once
+
+#include "color.h"
+
+#ifndef APA102_DEFAULT_BRIGHTNESS
+#    define APA102_DEFAULT_BRIGHTNESS 31
+#endif
+
+#define APA102_MAX_BRIGHTNESS 31
+
+extern uint8_t apa102_led_brightness;
+
+/* User Interface
+ *
+ * Input:
+ *         start_led:          An array of GRB data describing the LED colors
+ *         num_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
+ */
+void apa102_setleds(LED_TYPE *start_led, uint16_t num_leds);
+void apa102_set_brightness(uint8_t brightness);