[Keyboard] Initial firmware and keymaps for the CO60 PCB (#5959)

* Add: Initial firmware and keymaps for the CO60 PCB

* Apply suggestions from code review

Co-Authored-By: noroadsleft <18669334+noroadsleft@users.noreply.github.com>
Co-Authored-By: Drashna Jaelre <drashna@live.com>
Co-Authored-By: fauxpark <fauxpark@gmail.com>

* Update: Address reviewer comments

* Apply suggestions from code review

Co-Authored-By: Drashna Jaelre <drashna@live.com>

* Update: Reviewer changes

1 files changed, 240 insertions, 0 deletions

diff --git a/keyboards/handwired/co60/rev6/led.c b/keyboards/handwired/co60/rev6/led.c
new file mode 100644
index 0000000000..fe28ce2e8f
--- /dev/null
+++ b/keyboards/handwired/co60/rev6/led.c
@@ -0,0 +1,240 @@
+/*
+Copyright 2012 Jun Wako <wakojun@gmail.com>
+
+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 "hal.h"
+#include "led_custom.h"
+#include "rev6.h"
+#include "printf.h"
+
+static void breathing_callback(PWMDriver *pwmp);
+
+static PWMConfig pwmCFG = {
+  0xFFFF,                              /* PWM clock frequency  */
+  256,                                 /* PWM period (in ticks) 1S (1/10kHz=0.1mS 0.1ms*10000 ticks=1S) */
+  NULL,                                /* No Callback */
+  {
+      {PWM_OUTPUT_DISABLED, NULL},
+      {PWM_OUTPUT_DISABLED, NULL},
+      {PWM_OUTPUT_ACTIVE_HIGH, NULL}, /* Enable Channel 3 */
+      {PWM_OUTPUT_DISABLED, NULL}
+  },
+  0,                                  /* HW dependent part.*/
+  0
+};
+
+static PWMConfig pwmCFG_breathing = {
+  0xFFFF,                              /* 10kHz PWM clock frequency  */
+  256,                                 /* PWM period (in ticks) 1S (1/10kHz=0.1mS 0.1ms*10000 ticks=1S) */
+  breathing_callback,                  /* Breathing Callback */
+  {
+      {PWM_OUTPUT_DISABLED, NULL},
+      {PWM_OUTPUT_DISABLED, NULL},
+      {PWM_OUTPUT_ACTIVE_HIGH, NULL}, /* Enable Channel 3 */
+      {PWM_OUTPUT_DISABLED, NULL}
+  },
+  0,                                  /* HW dependent part.*/
+  0
+};
+
+// See http://jared.geek.nz/2013/feb/linear-led-pwm
+static uint16_t cie_lightness(uint16_t v) {
+  if (v <= 5243)   // if below 8% of max
+    return v / 9;  // same as dividing by 900%
+  else {
+    uint32_t y = (((uint32_t)v + 10486) << 8) / (10486 + 0xFFFFUL);  // add 16% of max and compare
+    // to get a useful result with integer division, we shift left in the expression above
+    // and revert what we've done again after squaring.
+    y = y * y * y >> 8;
+    if (y > 0xFFFFUL)  // prevent overflow
+      return 0xFFFFU;
+    else
+      return (uint16_t)y;
+  }
+}
+
+void backlight_init_ports(void) {
+  palSetPadMode(GPIOB, 8, PAL_MODE_ALTERNATE(2));
+  pwmStart(&PWMD4, &pwmCFG);
+  if (kb_backlight_config.enable) {
+    if (kb_backlight_config.breathing) {
+      breathing_enable();
+    } else {
+      backlight_set(kb_backlight_config.level);
+    }
+  } else {
+    backlight_set(0);
+  }
+}
+
+void backlight_set(uint8_t level) {
+  uint32_t duty = (uint32_t)(cie_lightness(0xFFFF * (uint32_t)level / BACKLIGHT_LEVELS));
+  if (level == 0) {
+    // Turn backlight off
+    // Disable channel 3 on PWM4
+    pwmDisableChannel(&PWMD4, 2);
+  } else {
+    // Turn backlight on
+    if (!is_breathing()) {
+      // Enable channel 3 on PWM4
+      pwmEnableChannel(&PWMD4, 2, PWM_FRACTION_TO_WIDTH(&PWMD4, 0xFFFF, duty));
+    }
+  }
+}
+
+uint8_t backlight_tick = 0;
+
+void backlight_task(void) {
+}
+
+#define BREATHING_NO_HALT  0
+#define BREATHING_HALT_OFF 1
+#define BREATHING_HALT_ON  2
+#define BREATHING_STEPS 128
+
+static uint8_t breathing_period = BREATHING_PERIOD;
+static uint8_t breathing_halt = BREATHING_NO_HALT;
+static uint16_t breathing_counter = 0;
+
+bool is_breathing(void) {
+    return PWMD4.config == &pwmCFG_breathing;
+}
+
+#define breathing_min() do {breathing_counter = 0;} while (0)
+#define breathing_max() do {breathing_counter = breathing_period * 256 / 2;} while (0)
+
+
+void breathing_interrupt_enable(void){
+    pwmStop(&PWMD4);
+    pwmStart(&PWMD4, &pwmCFG_breathing);
+    chSysLockFromISR();
+    pwmEnablePeriodicNotification(&PWMD4);
+    pwmEnableChannelI(
+      &PWMD4,
+      2,
+      PWM_FRACTION_TO_WIDTH(
+        &PWMD4,
+        0xFFFF,
+        0xFFFF
+      )
+    );
+    chSysUnlockFromISR();
+}
+
+void breathing_interrupt_disable(void){
+    pwmStop(&PWMD4);
+    pwmStart(&PWMD4, &pwmCFG);
+}
+
+void breathing_enable(void)
+{
+  breathing_counter = 0;
+  breathing_halt = BREATHING_NO_HALT;
+  breathing_interrupt_enable();
+}
+
+void breathing_pulse(void)
+{
+    if (kb_backlight_config.level == 0)
+      breathing_min();
+    else
+      breathing_max();
+    breathing_halt = BREATHING_HALT_ON;
+    breathing_interrupt_enable();
+}
+
+void breathing_disable(void)
+{
+    breathing_interrupt_disable();
+    // Restore backlight level
+    backlight_set(kb_backlight_config.level);
+}
+
+void breathing_self_disable(void)
+{
+  if (kb_backlight_config.level == 0)
+    breathing_halt = BREATHING_HALT_OFF;
+  else
+    breathing_halt = BREATHING_HALT_ON;
+}
+
+void breathing_toggle(void) {
+  if (is_breathing()){
+    breathing_disable();
+  } else {
+    breathing_enable();
+  }
+}
+
+void breathing_period_set(uint8_t value)
+{
+  if (!value)
+    value = 1;
+  breathing_period = value;
+}
+
+void breathing_period_default(void) {
+  breathing_period_set(BREATHING_PERIOD);
+}
+
+void breathing_period_inc(void)
+{
+  breathing_period_set(breathing_period+1);
+}
+
+void breathing_period_dec(void)
+{
+  breathing_period_set(breathing_period-1);
+}
+
+/* To generate breathing curve in python:
+ * from math import sin, pi; [int(sin(x/128.0*pi)**4*255) for x in range(128)]
+ */
+static const uint8_t breathing_table[BREATHING_STEPS] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 17, 20, 24, 28, 32, 36, 41, 46, 51, 57, 63, 70, 76, 83, 91, 98, 106, 113, 121, 129, 138, 146, 154, 162, 170, 178, 185, 193, 200, 207, 213, 220, 225, 231, 235, 240, 244, 247, 250, 252, 253, 254, 255, 254, 253, 252, 250, 247, 244, 240, 235, 231, 225, 220, 213, 207, 200, 193, 185, 178, 170, 162, 154, 146, 138, 129, 121, 113, 106, 98, 91, 83, 76, 70, 63, 57, 51, 46, 41, 36, 32, 28, 24, 20, 17, 15, 12, 10, 8, 6, 5, 4, 3, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+
+// Use this before the cie_lightness function.
+static inline uint16_t scale_backlight(uint16_t v) {
+  return v / BACKLIGHT_LEVELS * kb_backlight_config.level;
+}
+
+static void breathing_callback(PWMDriver *pwmp)
+{
+  (void)pwmp;
+  uint16_t interval = (uint16_t) breathing_period * 256 / BREATHING_STEPS;
+  // resetting after one period to prevent ugly reset at overflow.
+  breathing_counter = (breathing_counter + 1) % (breathing_period * 256);
+  uint8_t index = breathing_counter / interval % BREATHING_STEPS;
+
+  if (((breathing_halt == BREATHING_HALT_ON) && (index == BREATHING_STEPS / 2)) ||
+      ((breathing_halt == BREATHING_HALT_OFF) && (index == BREATHING_STEPS - 1)))
+  {
+      breathing_interrupt_disable();
+  }
+
+  uint32_t duty = cie_lightness(scale_backlight(breathing_table[index] * 256));
+
+  chSysLockFromISR();
+  pwmEnableChannelI(
+    &PWMD4,
+    2,
+    PWM_FRACTION_TO_WIDTH(
+      &PWMD4,
+      0xFFFF,
+      duty
+    )
+  );
+  chSysUnlockFromISR();
+}