pwm.c: make it usable from non-atomic blocks

[bike-lights.git] / firmware / pwm.c

diff --git a/firmware/pwm.c b/firmware/pwm.c
index b9b42c926cbd49cd449d36a76986bcdbc494b24d..56fb0884e125113a6885a3deb45cba9efe5ad6c8 100644 (file)
--- a/firmware/pwm.c
+++ b/firmware/pwm.c
@@ -1,12 +1,25 @@
 #include <avr/io.h>
 #include <avr/interrupt.h>
 #include <util/delay.h>
+#include <util/atomic.h>
 
 #include "lights.h"
 
 static uint16_t pwm[N_PWMLEDS];
 static volatile unsigned char step;
 
+static void enable_pll()
+{
+       /* Async clock */
+       PLLCSR = _BV(PLLE);
+
+       /* Synchronize to the phase lock */
+       _delay_us(100);
+       while ((PLLCSR & _BV(PLOCK)) == 0)
+               ;
+       PLLCSR |= _BV(PCKE);
+}
+
 void init_pwm()
 {
        int i;
@@ -16,14 +29,7 @@ void init_pwm()
        for (i = 0; i < N_PWMLEDS; i++)
                pwm[i] = 0;
 
-       /* Async clock */
-       PLLCSR = _BV(PLLE);
-
-       /* Synchronize to the phase lock */
-       _delay_ms(1);
-       while ((PLLCSR & _BV(PLOCK)) == 0)
-               ;
-       PLLCSR |= _BV(PCKE);
+       enable_pll();
 
        // PWM channel D is inverted, ...
        TCCR1C = _BV(COM1D1) | _BV(COM1D0) | _BV(PWM1D);
@@ -56,16 +62,20 @@ void susp_pwm()
        TCCR1D = TCCR1C = TCCR1B = TCCR1A = 0;
        TIMSK = 0;
        TIFR = 0;
+
+       PLLCSR &= ~(_BV(PLLE) | _BV(PCKE));
 }
 
 void pwm_off(unsigned char n)
 {
-       pwm[n] = 0;
-
-       switch (n) {
-       case 0: DDRB &= ~_BV(PB1); break;
-       case 1: DDRB &= ~_BV(PB3); break;
-       case 2: DDRB &= ~_BV(PB5); break;
+       ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+               pwm[n] = 0;
+
+               switch (n) {
+               case 0: DDRB &= ~_BV(PB1); break;
+               case 1: DDRB &= ~_BV(PB3); break;
+               case 2: DDRB &= ~_BV(PB5); break;
+               }
        }
 }
 
@@ -84,17 +94,14 @@ static void pwm_update_hw(unsigned char n)
        case 0:
                TC1H = hi;
                OCR1A = lo;
-               DDRB |= _BV(PB1);
                break;
        case 1:
                TC1H = hi;
                OCR1B = lo;
-               DDRB |= _BV(PB3);
                break;
        case 2:
                TC1H = hi;
                OCR1D = lo;
-               DDRB |= _BV(PB5);
                break;
        }
 }
@@ -104,8 +111,17 @@ void pwm_set(unsigned char n, uint16_t stride)
        if (((stride + (1 << PWM_STEP_SHIFT)) >> PWM_STEP_SHIFT) >= PWM_MAX)
                stride = PWM_MAX << PWM_STEP_SHIFT;
 
-       pwm[n] = stride;
-       pwm_update_hw(n);
+       ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+               pwm[n] = stride;
+
+               pwm_update_hw(n);
+
+               switch(n) {
+               case 0: DDRB |= _BV(PB1); break;
+               case 1: DDRB |= _BV(PB3); break;
+               case 2: DDRB |= _BV(PB5); break;
+               }
+       }
 }
 
 void pwm_timer()
@@ -120,18 +136,3 @@ void pwm_timer()
                        pwm_update_hw(i);
 }
 
-#if 0
-static void inline pwm_handler()
-{
-       OCR1A = pwmval[0];
-       OCR1B = pwmval[1];
-       OCR1D = pwmval[2];
-       TIMSK &= ~_BV(TOIE1);
-}
-
-ISR(TIMER1_OVF_vect)
-{
-       pwm_handler();
-}
-#endif
-