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Diffstat (limited to 'platforms/chibios/drivers/backlight_pwm.c')
-rw-r--r--platforms/chibios/drivers/backlight_pwm.c173
1 files changed, 173 insertions, 0 deletions
diff --git a/platforms/chibios/drivers/backlight_pwm.c b/platforms/chibios/drivers/backlight_pwm.c
new file mode 100644
index 0000000000..01e6f71307
--- /dev/null
+++ b/platforms/chibios/drivers/backlight_pwm.c
@@ -0,0 +1,173 @@
+#include "backlight.h"
+#include "gpio.h"
+#include "wait.h"
+#include <hal.h>
+
+// Maximum duty cycle limit
+#ifndef BACKLIGHT_LIMIT_VAL
+# define BACKLIGHT_LIMIT_VAL 255
+#endif
+
+#ifndef BACKLIGHT_PAL_MODE
+# if defined(USE_GPIOV1)
+# define BACKLIGHT_PAL_MODE PAL_MODE_ALTERNATE_PUSHPULL
+# else
+// GPIOV2 && GPIOV3
+# define BACKLIGHT_PAL_MODE 2
+# endif
+#endif
+
+// GENERIC
+#ifndef BACKLIGHT_PWM_DRIVER
+# define BACKLIGHT_PWM_DRIVER PWMD4
+#endif
+#ifndef BACKLIGHT_PWM_CHANNEL
+# define BACKLIGHT_PWM_CHANNEL 3
+#endif
+
+// Support for pins which are on TIM1_CH1N - requires STM32_PWM_USE_ADVANCED
+#ifdef BACKLIGHT_PWM_COMPLEMENTARY_OUTPUT
+# if BACKLIGHT_ON_STATE == 1
+# define PWM_OUTPUT_MODE PWM_COMPLEMENTARY_OUTPUT_ACTIVE_LOW;
+# else
+# define PWM_OUTPUT_MODE PWM_COMPLEMENTARY_OUTPUT_ACTIVE_HIGH;
+# endif
+#else
+# if BACKLIGHT_ON_STATE == 1
+# define PWM_OUTPUT_MODE PWM_OUTPUT_ACTIVE_HIGH;
+# else
+# define PWM_OUTPUT_MODE PWM_OUTPUT_ACTIVE_LOW;
+# endif
+#endif
+
+#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) {
+ 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 uint32_t rescale_limit_val(uint32_t val) {
+ // rescale the supplied backlight value to be in terms of the value limit
+ return (val * (BACKLIGHT_LIMIT_VAL + 1)) / 256;
+}
+
+void backlight_init_ports(void) {
+#ifdef USE_GPIOV1
+ palSetPadMode(PAL_PORT(BACKLIGHT_PIN), PAL_PAD(BACKLIGHT_PIN), BACKLIGHT_PAL_MODE);
+#else
+ palSetPadMode(PAL_PORT(BACKLIGHT_PIN), PAL_PAD(BACKLIGHT_PIN), PAL_MODE_ALTERNATE(BACKLIGHT_PAL_MODE));
+#endif
+
+ pwmCFG.channels[BACKLIGHT_PWM_CHANNEL - 1].mode = PWM_OUTPUT_MODE;
+ pwmStart(&BACKLIGHT_PWM_DRIVER, &pwmCFG);
+
+ backlight_set(get_backlight_level());
+
+#ifdef BACKLIGHT_BREATHING
+ chVTObjectInit(&breathing_vt);
+ if (is_backlight_breathing()) {
+ breathing_enable();
+ }
+#endif
+}
+
+void backlight_set(uint8_t level) {
+ if (level > BACKLIGHT_LEVELS) {
+ level = BACKLIGHT_LEVELS;
+ }
+
+ if (level == 0) {
+ // Turn backlight off
+ pwmDisableChannel(&BACKLIGHT_PWM_DRIVER, BACKLIGHT_PWM_CHANNEL - 1);
+ } else {
+ // Turn backlight on
+ uint32_t duty = (uint32_t)(cie_lightness(rescale_limit_val(0xFFFF * (uint32_t)level / BACKLIGHT_LEVELS)));
+ pwmEnableChannel(&BACKLIGHT_PWM_DRIVER, BACKLIGHT_PWM_CHANNEL - 1, PWM_FRACTION_TO_WIDTH(&BACKLIGHT_PWM_DRIVER, 0xFFFF, duty));
+ }
+}
+
+void backlight_task(void) {}
+
+#ifdef BACKLIGHT_BREATHING
+
+# define BREATHING_STEPS 128
+
+/* To generate breathing curve in python:
+ * from math import sin, pi; [int(sin(x/128.0*pi)**4*255) for x in range(128)]
+ */
+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};
+
+static void breathing_callback(virtual_timer_t *vtp, void *p);
+
+bool is_breathing(void) {
+ return chVTIsArmed(&breathing_vt);
+}
+
+void breathing_enable(void) {
+ /* Update frequency is 256Hz -> 3906us intervals */
+ chVTSetContinuous(&breathing_vt, TIME_US2I(3906), breathing_callback, NULL);
+}
+
+void breathing_disable(void) {
+ chVTReset(&breathing_vt);
+
+ // Restore backlight level
+ backlight_set(get_backlight_level());
+}
+
+// Use this before the cie_lightness function.
+static inline uint16_t scale_backlight(uint16_t v) {
+ return v / BACKLIGHT_LEVELS * get_backlight_level();
+}
+
+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;
+
+ // resetting after one period to prevent ugly reset at overflow.
+ static uint16_t breathing_counter = 0;
+ breathing_counter = (breathing_counter + 1) % (breathing_period * 256);
+ uint8_t index = breathing_counter / interval % BREATHING_STEPS;
+ uint32_t duty = cie_lightness(rescale_limit_val(scale_backlight(breathing_table[index] * 256)));
+
+ chSysLockFromISR();
+ pwmEnableChannelI(&BACKLIGHT_PWM_DRIVER, BACKLIGHT_PWM_CHANNEL - 1, PWM_FRACTION_TO_WIDTH(&BACKLIGHT_PWM_DRIVER, 0xFFFF, duty));
+ chSysUnlockFromISR();
+}
+
+// TODO: integrate generic pulse solution
+void breathing_pulse(void) {
+ backlight_set(is_backlight_enabled() ? 0 : BACKLIGHT_LEVELS);
+ wait_ms(10);
+ backlight_set(is_backlight_enabled() ? get_backlight_level() : 0);
+}
+
+#endif