backlight.cpp
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#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 shutdown() {
GPIOC.MODER()->setMode(6, GPIO::MODER::Mode::Analog);
GPIOC.PUPDR()->setPull(6, GPIO::PUPDR::Pull::None);
}
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);
}
}
}
}
}