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[Core] PWM Backlight for RP2040 (#17706)

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This commit is contained in:
Stefan Kerkmann 2022-10-04 23:10:24 +02:00 • committed by GitHub
parent b6ea8837e4
commit 996a9006d3
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GPG key ID: 4AEE18F83AFDEB23
14 changed files with 107 additions and 22 deletions
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51
quantum/backlight/backlight_chibios.c
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@ -40,16 +40,22 @@
# endif
#endif
static PWMConfig pwmCFG = {0xFFFF, /* PWM clock frequency */
256, /* PWM period (in ticks) 1S (1/10kHz=0.1mS 0.1ms*10000 ticks=1S) */
NULL, /* Breathing Callback */
{ /* Default all channels to disabled - Channels will be configured durring init */
{PWM_OUTPUT_DISABLED, NULL},
{PWM_OUTPUT_DISABLED, NULL},
{PWM_OUTPUT_DISABLED, NULL},
{PWM_OUTPUT_DISABLED, NULL}},
0, /* HW dependent part.*/
0};
#ifndef BACKLIGHT_PWM_COUNTER_FREQUENCY
# define BACKLIGHT_PWM_COUNTER_FREQUENCY 0xFFFF
#endif
#ifndef BACKLIGHT_PWM_PERIOD
# define BACKLIGHT_PWM_PERIOD 256
#endif
static PWMConfig pwmCFG = {
.frequency = BACKLIGHT_PWM_COUNTER_FREQUENCY, /* PWM clock frequency */
.period = BACKLIGHT_PWM_PERIOD, /* PWM period in counter ticks. e.g. clock frequency is 10KHz, period is 256 ticks then t_period is 25.6ms */
};
#ifdef BACKLIGHT_BREATHING
static virtual_timer_t breathing_vt;
#endif
// See http://jared.geek.nz/2013/feb/linear-led-pwm
static uint16_t cie_lightness(uint16_t v) {
@ -60,10 +66,11 @@ static uint16_t cie_lightness(uint16_t v) {
// 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
if (y > 0xFFFFUL) { // prevent overflow
return 0xFFFFU;
else
} else {
return (uint16_t)y;
}
}
}
@ -85,6 +92,7 @@ void backlight_init_ports(void) {
backlight_set(get_backlight_level());
#ifdef BACKLIGHT_BREATHING
chVTObjectInit(&breathing_vt);
if (is_backlight_breathing()) {
breathing_enable();
}
@ -92,7 +100,9 @@ void backlight_init_ports(void) {
}
void backlight_set(uint8_t level) {
if (level > BACKLIGHT_LEVELS) level = BACKLIGHT_LEVELS;
if (level > BACKLIGHT_LEVELS) {
level = BACKLIGHT_LEVELS;
}
if (level == 0) {
// Turn backlight off
@ -115,20 +125,19 @@ void backlight_task(void) {}
*/
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};
void breathing_callback(PWMDriver *pwmp);
static void breathing_callback(virtual_timer_t *vtp, void *p);
bool is_breathing(void) {
return pwmCFG.callback != NULL;
return chVTIsArmed(&breathing_vt);
}
void breathing_enable(void) {
pwmCFG.callback = breathing_callback;
pwmEnablePeriodicNotification(&BACKLIGHT_PWM_DRIVER);
/* Update frequency is 256Hz -> 3906us intervals */
chVTSetContinuous(&breathing_vt, TIME_US2I(3906), breathing_callback, NULL);
}
void breathing_disable(void) {
pwmCFG.callback = NULL;
pwmDisablePeriodicNotification(&BACKLIGHT_PWM_DRIVER);
chVTReset(&breathing_vt);
// Restore backlight level
backlight_set(get_backlight_level());
@ -139,7 +148,7 @@ static inline uint16_t scale_backlight(uint16_t v) {
return v / BACKLIGHT_LEVELS * get_backlight_level();
}
void breathing_callback(PWMDriver *pwmp) {
static void breathing_callback(virtual_timer_t *vtp, void *p) {
uint8_t breathing_period = get_breathing_period();
uint16_t interval = (uint16_t)breathing_period * 256 / BREATHING_STEPS;
@ -150,7 +159,7 @@ void breathing_callback(PWMDriver *pwmp) {
uint32_t duty = cie_lightness(rescale_limit_val(scale_backlight(breathing_table[index] * 256)));
chSysLockFromISR();
pwmEnableChannelI(pwmp, BACKLIGHT_PWM_CHANNEL - 1, PWM_FRACTION_TO_WIDTH(&BACKLIGHT_PWM_DRIVER, 0xFFFF, duty));
pwmEnableChannelI(&BACKLIGHT_PWM_DRIVER, BACKLIGHT_PWM_CHANNEL - 1, PWM_FRACTION_TO_WIDTH(&BACKLIGHT_PWM_DRIVER, 0xFFFF, duty));
chSysUnlockFromISR();
}