Enable PWM Support for Planck EZ Indicator Lights (#6473)

* remove led layer code

* enable PWM on STM32F303

* Unusable PWM code

* Updated PWM Stuff?

* PWM Semi-working

* Both LEDs working at the same time

* Update names

* Add led level functions

* Add LED levels and persistent settings

* Revert change due to issues with timing related code

* Review feedback and minor cleanup

4 files changed, 164 insertions, 30 deletions

diff --git a/keyboards/planck/ez/ez.c b/keyboards/planck/ez/ez.c
index e739b90b8..8734042a4 100644
--- a/keyboards/planck/ez/ez.c
+++ b/keyboards/planck/ez/ez.c
@@ -14,6 +14,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include "ez.h"
+#include "ch.h"
+#include "hal.h"
+ keyboard_config_t keyboard_config;
+
 
 #ifdef RGB_MATRIX_ENABLE
 const is31_led g_is31_leds[DRIVER_LED_TOTAL] = {
@@ -112,39 +116,148 @@ void suspend_power_down_kb(void) {
 }
 #endif
 
-void matrix_init_kb(void) {
-  matrix_init_user();
+/* Left B9   Right B8 */
+
+// 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;
+  }
+}
+
+static PWMConfig pwmCFG = {
+    0xFFFF,/* PWM clock frequency  */
+    256,/* initial PWM period (in ticks) 1S (1/10kHz=0.1mS 0.1ms*10000 ticks=1S) */
+    NULL,
+    {
+        {PWM_OUTPUT_DISABLED, NULL}, /* channel 0 -> TIM1-CH1 = PA8 */
+        {PWM_OUTPUT_DISABLED, NULL}, /* channel 1 -> TIM1-CH2 = PA9 */
+        {PWM_OUTPUT_ACTIVE_HIGH, NULL},
+        {PWM_OUTPUT_ACTIVE_HIGH, NULL}
+    },
+    0, /* HW dependent part.*/
+    0
+};
+
+static uint32_t planck_ez_right_led_duty;
+static uint32_t planck_ez_left_led_duty;
+
+void planck_ez_right_led_level(uint8_t level) {
+    planck_ez_right_led_duty = (uint32_t)(cie_lightness(0xFFFF * (uint32_t) level / 255));
+    if (level == 0) {
+        // Turn backlight off
+        pwmDisableChannel(&PWMD4, 2);
+    } else {
+        // Turn backlight on
+        pwmEnableChannel(&PWMD4, 2, PWM_FRACTION_TO_WIDTH(&PWMD4,0xFFFF,planck_ez_right_led_duty));
+    }
+}
 
-  palSetPadMode(GPIOB, 8, PAL_MODE_OUTPUT_PUSHPULL);
-  palSetPadMode(GPIOB, 9, PAL_MODE_OUTPUT_PUSHPULL);
 
-  palClearPad(GPIOB, 8);
-  palClearPad(GPIOB, 9);
+void planck_ez_right_led_on(void){
+    pwmEnableChannel(&PWMD4, 2, PWM_FRACTION_TO_WIDTH(&PWMD4,0xFFFF,planck_ez_right_led_duty));
 }
 
-void matrix_scan_kb(void) {
-  matrix_scan_user();
+void planck_ez_right_led_off(void){
+    pwmDisableChannel(&PWMD4, 2);
 }
 
-uint32_t layer_state_set_kb(uint32_t state) {
-
-  palClearPad(GPIOB, 8);
-  palClearPad(GPIOB, 9);
-  state = layer_state_set_user(state);
-  uint8_t layer = biton32(state);
-  switch (layer) {
-      case 3:
-        palSetPad(GPIOB, 9);
-        break;
-      case 4:
-        palSetPad(GPIOB, 8);
-        break;
-      case 6:
-        palSetPad(GPIOB, 9);
-        palSetPad(GPIOB, 8);
-        break;
-      default:
-        break;
+void planck_ez_left_led_level(uint8_t level) {
+    planck_ez_left_led_duty = (uint32_t)(cie_lightness(0xFFFF * (uint32_t) level / 255));
+    if (level == 0) {
+        // Turn backlight off
+        pwmDisableChannel(&PWMD4, 3);
+    } else {
+        // Turn backlight on
+        pwmEnableChannel(&PWMD4, 3, PWM_FRACTION_TO_WIDTH(&PWMD4,0xFFFF,planck_ez_left_led_duty));
+    }
+}
+
+void planck_ez_left_led_on(void){
+    pwmEnableChannel(&PWMD4, 3, PWM_FRACTION_TO_WIDTH(&PWMD4,0xFFFF,planck_ez_left_led_duty));
+}
+
+void planck_ez_left_led_off(void){
+    pwmDisableChannel(&PWMD4, 3);
+}
+
+
+void led_initialize_hardware(void) {
+    pwmStart(&PWMD4, &pwmCFG);
+
+    // set up defaults
+    planck_ez_right_led_level((uint8_t)keyboard_config.led_level * 255 / 4 );
+    palSetPadMode(GPIOB, 8, PAL_MODE_ALTERNATE(2));
+    planck_ez_left_led_level((uint8_t)keyboard_config.led_level * 255 / 4 );
+    palSetPadMode(GPIOB, 9, PAL_MODE_ALTERNATE(2));
+
+
+    // turn LEDs off by default
+    planck_ez_left_led_off();
+    planck_ez_right_led_off();
+}
+
+void keyboard_pre_init_kb(void) {
+    // read kb settings from eeprom
+    keyboard_config.raw = eeconfig_read_kb();
+
+    // initialize settings for front LEDs
+    led_initialize_hardware();
+}
+
+void eeconfig_init_kb(void) {  // EEPROM is getting reset!
+    keyboard_config.raw = 0;
+    keyboard_config.led_level = 4;
+    eeconfig_update_kb(keyboard_config.raw);
+    eeconfig_init_user();
+}
+
+layer_state_t layer_state_set_kb(layer_state_t state) {
+    planck_ez_left_led_off();
+    planck_ez_right_led_off();
+    state = layer_state_set_user(state);
+    uint8_t layer = biton32(state);
+    switch (layer) {
+        case 3:
+            planck_ez_left_led_on();
+            break;
+        case 4:
+            planck_ez_right_led_on();
+            break;
+        case 6:
+            planck_ez_right_led_on();
+            planck_ez_left_led_on();
+            break;
+        default:
+            break;
     }
     return state;
 }
+
+
+bool process_record_kb(uint16_t keycode, keyrecord_t *record) {
+    switch (keycode) {
+        case LED_LEVEL:
+            if (record->event.pressed) {
+                 keyboard_config.led_level++;
+                 if (keyboard_config.led_level > 4) {
+                    keyboard_config.led_level = 0;
+                 }
+                 planck_ez_right_led_level((uint8_t)keyboard_config.led_level * 255 / 4 );
+                 planck_ez_left_led_level((uint8_t)keyboard_config.led_level * 255 / 4 );
+                 eeconfig_update_kb(keyboard_config.raw);
+                 layer_state_set_kb(layer_state);
+            }
+            break;
+    }
+    return true;
+}
diff --git a/keyboards/planck/ez/ez.h b/keyboards/planck/ez/ez.h
index 55c403242..e2ddaf3ce 100644
--- a/keyboards/planck/ez/ez.h
+++ b/keyboards/planck/ez/ez.h
@@ -50,3 +50,24 @@ LAYOUT_planck_1x2uC( \
 #define KEYMAP LAYOUT_ortho_4x12
 #define LAYOUT_planck_mit LAYOUT_planck_1x2uC
 #define LAYOUT_planck_grid LAYOUT_ortho_4x12
+
+void planck_ez_right_led_on(void);
+void planck_ez_right_led_off(void);
+void planck_ez_right_led_level(uint8_t level);
+void planck_ez_left_led_on(void);
+void planck_ez_left_led_off(void);
+void planck_ez_left_led_level(uint8_t level);
+
+enum planck_ez_keycodes {
+    LED_LEVEL = SAFE_RANGE,
+    EZ_SAFE_RANGE,
+};
+
+typedef union {
+  uint32_t raw;
+  struct {
+    uint8_t    led_level :3;
+  };
+} keyboard_config_t;
+
+extern keyboard_config_t keyboard_config;
diff --git a/quantum/stm32/halconf.h b/quantum/stm32/halconf.h
index c3e0cbb72..a14ace02b 100644
--- a/quantum/stm32/halconf.h
+++ b/quantum/stm32/halconf.h
@@ -111,7 +111,7 @@
  * @brief   Enables the PWM subsystem.
  */
 #if !defined(HAL_USE_PWM) || defined(__DOXYGEN__)
-#define HAL_USE_PWM                 FALSE
+#define HAL_USE_PWM                 TRUE
 #endif
 
 /**
diff --git a/quantum/stm32/mcuconf.h b/quantum/stm32/mcuconf.h
index 36f8ca225..32a73fb38 100644
--- a/quantum/stm32/mcuconf.h
+++ b/quantum/stm32/mcuconf.h
@@ -183,9 +183,9 @@
  */
 #define STM32_PWM_USE_ADVANCED              FALSE
 #define STM32_PWM_USE_TIM1                  FALSE
-#define STM32_PWM_USE_TIM2                  TRUE
+#define STM32_PWM_USE_TIM2                  FALSE
 #define STM32_PWM_USE_TIM3                  TRUE
-#define STM32_PWM_USE_TIM4                  FALSE
+#define STM32_PWM_USE_TIM4                  TRUE
 #define STM32_PWM_USE_TIM8                  FALSE
 #define STM32_PWM_TIM1_IRQ_PRIORITY         7
 #define STM32_PWM_TIM2_IRQ_PRIORITY         7