ARM backlight - timer implementation (#8291)
* Add GPT timer based backlight driver * Update to tim15 to avoid conflict with audio * Update quantum/backlight/backlight_timer.cmaster
Joel Challis
James Young
parent
568cae28ec
commit
21a00b7f02
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@ -264,7 +264,7 @@ ifeq ($(strip $(BACKLIGHT_CUSTOM_DRIVER)), yes)
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BACKLIGHT_DRIVER := custom
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endif
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VALID_BACKLIGHT_TYPES := pwm software custom
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VALID_BACKLIGHT_TYPES := pwm timer software custom
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BACKLIGHT_ENABLE ?= no
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BACKLIGHT_DRIVER ?= pwm
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@ -144,7 +144,7 @@
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#define STM32_GPT_USE_TIM6 TRUE
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#define STM32_GPT_USE_TIM7 TRUE
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#define STM32_GPT_USE_TIM8 TRUE
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#define STM32_GPT_USE_TIM15 FALSE
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#define STM32_GPT_USE_TIM15 TRUE
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#define STM32_GPT_USE_TIM16 FALSE
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#define STM32_GPT_USE_TIM17 FALSE
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#define STM32_GPT_TIM1_IRQ_PRIORITY 7
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@ -0,0 +1,167 @@
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#include "quantum.h"
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#include "backlight.h"
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#include "backlight_driver_common.h"
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#include "debug.h"
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#ifndef BACKLIGHT_GPT_DRIVER
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# define BACKLIGHT_GPT_DRIVER GPTD15
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#endif
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// Platform specific implementations
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static void backlight_timer_configure(bool enable);
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static void backlight_timer_set_duty(uint16_t duty);
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static uint16_t backlight_timer_get_duty(void);
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// See http://jared.geek.nz/2013/feb/linear-led-pwm
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static uint16_t cie_lightness(uint16_t v) {
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if (v <= 5243) // if below 8% of max
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return v / 9; // same as dividing by 900%
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else {
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uint32_t y = (((uint32_t)v + 10486) << 8) / (10486 + 0xFFFFUL); // add 16% of max and compare
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// to get a useful result with integer division, we shift left in the expression above
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// and revert what we've done again after squaring.
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y = y * y * y >> 8;
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if (y > 0xFFFFUL) // prevent overflow
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return 0xFFFFU;
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else
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return (uint16_t)y;
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}
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}
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void backlight_init_ports(void) {
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backlight_pins_init();
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backlight_set(get_backlight_level());
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#ifdef BACKLIGHT_BREATHING
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if (is_backlight_breathing()) {
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breathing_enable();
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}
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#endif
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}
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void backlight_set(uint8_t level) {
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if (level > BACKLIGHT_LEVELS) level = BACKLIGHT_LEVELS;
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backlight_pins_off();
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backlight_timer_set_duty(cie_lightness(0xFFFFU / BACKLIGHT_LEVELS * level));
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backlight_timer_configure(level != 0);
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}
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static void backlight_timer_top(void) {
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#ifdef BACKLIGHT_BREATHING
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if (is_breathing()) {
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breathing_task();
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}
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#endif
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if (backlight_timer_get_duty() > 256) {
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backlight_pins_on();
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}
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}
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static void backlight_timer_cmp(void) { backlight_pins_off(); }
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void backlight_task(void) {}
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#ifdef BACKLIGHT_BREATHING
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# define BREATHING_STEPS 128
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static bool breathing = false;
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static uint16_t breathing_counter = 0;
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/* To generate breathing curve in python:
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* from math import sin, pi; [int(sin(x/128.0*pi)**4*255) for x in range(128)]
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*/
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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};
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// Use this before the cie_lightness function.
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static inline uint16_t scale_backlight(uint16_t v) { return v / BACKLIGHT_LEVELS * get_backlight_level(); }
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void breathing_task(void) {
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uint8_t breathing_period = get_breathing_period();
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uint16_t interval = (uint16_t)breathing_period * 256 / BREATHING_STEPS;
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// resetting after one period to prevent ugly reset at overflow.
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breathing_counter = (breathing_counter + 1) % (breathing_period * 256);
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uint8_t index = breathing_counter / interval % BREATHING_STEPS;
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// printf("index:%u\n", index);
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backlight_timer_set_duty(cie_lightness(scale_backlight((uint16_t)breathing_table[index] * 256)));
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}
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bool is_breathing(void) { return breathing; }
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void breathing_enable(void) {
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breathing_counter = 0;
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breathing = true;
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}
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void breathing_disable(void) { breathing = false; }
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void breathing_pulse(void) {
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backlight_set(is_backlight_enabled() ? 0 : BACKLIGHT_LEVELS);
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wait_ms(10);
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backlight_set(is_backlight_enabled() ? get_backlight_level() : 0);
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}
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#endif
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#ifdef PROTOCOL_CHIBIOS
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// On Platforms where timers fire every tick and have no capture/top events
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// - fake event in the normal timer callback
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uint16_t s_duty = 0;
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static void timerCallback(void) {
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/* Software PWM
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* timer:1111 1111 1111 1111
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* \______/| \_______/____ count(0-255)
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* \ \______________ unused(1)
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* \__________________ index of step table(0-127)
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*/
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// this works for cca 65536 irqs/sec
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static union {
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uint16_t raw;
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struct {
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uint16_t count : 8;
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uint8_t dummy : 1;
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uint8_t index : 7;
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} pwm;
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} timer = {.raw = 0};
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timer.raw++;
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if (timer.pwm.count == 0) {
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// LED on
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backlight_timer_top();
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} else if (timer.pwm.count == (s_duty / 256)) {
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// LED off
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backlight_timer_cmp();
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}
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}
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static void backlight_timer_set_duty(uint16_t duty) { s_duty = duty; }
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static uint16_t backlight_timer_get_duty(void) { return s_duty; }
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// ChibiOS - Map GPT timer onto Software PWM
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static void gptTimerCallback(GPTDriver *gptp) {
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(void)gptp;
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timerCallback();
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}
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static void backlight_timer_configure(bool enable) {
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static const GPTConfig gptcfg = {1000000, gptTimerCallback, 0, 0};
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static bool s_init = false;
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if (!s_init) {
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gptStart(&BACKLIGHT_GPT_DRIVER, &gptcfg);
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s_init = true;
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}
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if (enable) {
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gptStartContinuous(&BACKLIGHT_GPT_DRIVER, gptcfg.frequency / 0xFFFF);
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} else {
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gptStopTimer(&BACKLIGHT_GPT_DRIVER);
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}
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}
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#endif
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