[ion] Add a backlight namespace

Change-Id: I0b9ec9a1b342d4b949776f0303eca69a28d1de91

ion/include/ion.h

@@ -1,6 +1,7 @@
 #ifndef ION_ION_H
 #define ION_ION_H
 
+#include <ion/backlight.h>
 #include <ion/battery.h>
 #include <ion/display.h>
 #include <ion/events.h>

ion/include/ion/backlight.h

@@ -0,0 +1,15 @@
+#ifndef ION_BACKLIGHT_H
+#define ION_BACKLIGHT_H
+
+#include <stdint.h>
+
+namespace Ion {
+namespace Backlight {
+
+void setBrightness(uint8_t b);
+uint8_t brightness();
+
+}
+}
+
+#endif

ion/include/ion/display.h

@@ -21,8 +21,6 @@ void pushRect(KDRect r, const KDColor * pixels);
 void pushRectUniform(KDRect r, KDColor c);
 void pullRect(KDRect r, KDColor * pixels);
 
-void setBacklightIntensity(uint8_t intensity);
-
 constexpr int Width = 320;
 constexpr int Height = 240;
 

ion/src/device/Makefile

@@ -1,6 +1,7 @@
 include ion/src/shared/Makefile
 include ion/src/device/boot/Makefile
 objs += $(addprefix ion/src/device/, \
+  backlight.o \
   battery.o\
   device.o\
   display.o\

ion/src/device/backlight.cpp

@@ -0,0 +1,80 @@
+#include <ion.h>
+#include "regs/regs.h"
+#include "backlight.h"
+
+/* This driver controls the RT9365 LED driver.
+ * This chip allows the brightness to be set to 16 different values. It starts
+ * at full brightness on power on. Applying a pulse on the EN pin will select
+ * the next value in decreasing order. Once it reaches the minimal value, the
+ * next pulse will loop back to full brightness. */
+
+// Public Ion::Backlight methods
+
+namespace Ion {
+namespace Backlight {
+
+void setBrightness(uint8_t b) {
+  Device::setLevel(b >> 4);
+}
+
+uint8_t brightness() {
+  return Device::level() << 4;
+}
+
+}
+}
+
+// Private Ion::Backlight::Device methods
+
+namespace Ion {
+namespace Backlight {
+namespace Device {
+
+static uint8_t sLevel;
+
+void init() {
+  GPIOC.MODER()->setMode(6, GPIO::MODER::Mode::Output);
+  sLevel = 0xF;
+  resume();
+}
+
+void suspend() {
+  GPIOC.ODR()->set(6, false);
+  msleep(3); // Might not need to be blocking
+}
+
+void resume() {
+  GPIOC.ODR()->set(6, true);
+  usleep(50);
+  uint8_t level = sLevel;
+  sLevel = 0xF;
+  setLevel(level);
+}
+
+void setLevel(uint8_t level) {
+  // From sLevel = 12 to level 7 : 5 pulses
+  // From sLevel = 5 to level 9 : 12 pulses (5 to go to level 16, and 7 to 9)
+  if (sLevel < level) {
+    sendPulses(16 + sLevel - level);
+  } else {
+    sendPulses(sLevel - level);
+  }
+  sLevel = level;
+}
+
+uint8_t level() {
+  return sLevel;
+}
+
+void sendPulses(int n) {
+  for (int i=0; i<n; i++) {
+    GPIOC.ODR()->set(6, false);
+    usleep(20);
+    GPIOC.ODR()->set(6, true);
+    usleep(20);
+  }
+}
+
+}
+}
+}

ion/src/device/backlight.h

@@ -0,0 +1,27 @@
+#ifndef ION_DEVICE_BACKLIGHT_H
+#define ION_DEVICE_BACKLIGHT_H
+
+#include <ion/backlight.h>
+
+namespace Ion {
+namespace Backlight {
+namespace Device {
+
+/*  Pin | Role              | Mode                  | Function
+ * -----+-------------------+-----------------------+----------
+ *  PC6 | Backlight Enable  | Output                |
+ */
+
+void init();
+void suspend();
+void resume();
+void setLevel(uint8_t level);
+uint8_t level();
+
+void sendPulses(int n);
+
+}
+}
+}
+
+#endif

ion/src/device/device.cpp

@@ -9,6 +9,7 @@ extern "C" {
 #include "keyboard.h"
 #include "battery.h"
 #include "sd_card.h"
+#include "backlight.h"
 
 #define USE_SD_CARD 0
 
@@ -37,8 +38,7 @@ void Ion::Device::init() {
   Display::Device::init();
   Keyboard::Device::init();
   Battery::Device::init();
-
-  Display::setBacklightIntensity(0xFF);
+  Backlight::Device::init();
 #if USE_SD_CARD
   SDCard::Device::init();
 #endif

ion/src/device/led.cpp

@@ -11,9 +11,6 @@ void Ion::LED::setColor(KDColor c) {
   TIM3.CCR4()->set(Device::dutyCycleForUInt8(c.green()));
 }
 
-void Ion::Display::setBacklightIntensity(uint8_t intensity) {
-}
-
 // Private Ion::Device::LED methods
 
 namespace Ion {