Merge pull request #1122 from stevew817/master

[Silicon Labs] Bugfixes in PwmOut

libraries/mbed/targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/pwmout_api.c

@@ -24,52 +24,31 @@
 #include "pinmap.h"
 #include "PeripheralPins.h"
 #include "device_peripherals.h"
+#include "sleepmodes.h"
 
 #include "em_cmu.h"
 #include "em_gpio.h"
 #include "em_timer.h"
 
-static int clockfreq;
-static int prescaler_div;
+static int pwm_clockfreq;
+static int pwm_prescaler_div;
 
-uint8_t pwmout_get_index(pwmout_t *obj)
-{
-    return 0;
-}
-
-void pwmout_preinit(pwmout_t *obj, PinName pin)
-{
-    obj->channel = (PWMName) pinmap_peripheral(pin, PinMap_PWM);
-    obj->pin = pin;
+uint32_t pwmout_get_channel_route(pwmout_t *obj) {
 	MBED_ASSERT(obj->channel != (PWMName) NC);
-}
 
-void pwmout_init(pwmout_t *obj, PinName pin)
-{
-	pwmout_preinit(obj, pin);
-
-    /* Enable correct channel */
 	switch (obj->channel) {
 		case PWM_CH0:
-            PWM_TIMER->ROUTE |= TIMER_ROUTE_CC0PEN;
+			return TIMER_ROUTE_CC0PEN;
 			break;
 		case PWM_CH1:
-            PWM_TIMER->ROUTE |= TIMER_ROUTE_CC1PEN;
+			return TIMER_ROUTE_CC1PEN;
 			break;
 		case PWM_CH2:
-            PWM_TIMER->ROUTE |= TIMER_ROUTE_CC2PEN;
+			return TIMER_ROUTE_CC2PEN;
 			break;
-
+		default:
+			return 0;
 	}
-
-    /* Route correct channel to location 1 */
-    PWM_TIMER->ROUTE |= PWM_ROUTE;
-
-    /*HFPER is the default clock we will use. It has a frequency of 14MHz*/
-    clockfreq = REFERENCE_FREQUENCY;
-
-    /* Set default 20ms frequency and 0ms pulse width */
-    pwmout_period(obj, 0.02);
 }
 
 void pwmout_enable_pins(pwmout_t *obj, uint8_t enable)
@@ -84,24 +63,71 @@ void pwmout_enable_pins(pwmout_t *obj, uint8_t enable)
 
 void pwmout_enable(pwmout_t *obj, uint8_t enable)
 {
-    TIMER_Init_TypeDef timerInit = TIMER_INIT_DEFAULT;
-
-    if (enable) {
 	/* Start with default CC (Compare/Capture) channel parameters */
 	TIMER_InitCC_TypeDef timerCCInit = TIMER_INITCC_DEFAULT;
-
+    if (enable) {
         /* Set mode to PWM */
         timerCCInit.mode = timerCCModePWM;
+    }
 
     /* Configure CC channel */
     TIMER_InitCC(PWM_TIMER, obj->channel, &timerCCInit);
-        TIMER_Init(PWM_TIMER, &timerInit);
-    } else {
-        timerInit.enable = false;
-        TIMER_Init(PWM_TIMER, &timerInit);
-    }
 }
 
+void pwmout_init(pwmout_t *obj, PinName pin)
+{
+	obj->channel = (PWMName) pinmap_peripheral(pin, PinMap_PWM);
+	obj->pin = pin;
+	MBED_ASSERT(obj->channel != (PWMName) NC);
+
+	/* Turn on clock */
+	CMU_ClockEnable(PWM_TIMER_CLOCK, true);
+
+	/* Turn on timer */
+	if(!(PWM_TIMER->STATUS & TIMER_STATUS_RUNNING)) {
+		TIMER_Init_TypeDef timerInit = TIMER_INIT_DEFAULT;
+		TIMER_Init(PWM_TIMER, &timerInit);
+	}
+
+    /* Enable correct channel */
+	uint32_t routeloc = pwmout_get_channel_route(obj);
+	if(PWM_TIMER->ROUTE & routeloc) {
+		//This channel was already in use
+		//TODO: gracefully handle this case
+	} else {
+		//This channel was unused up to now
+		PWM_TIMER->ROUTE |= routeloc;
+		blockSleepMode(EM1);
+
+		//TODO: check if any channel was up already, then don't re-init timer
+		pwmout_enable(obj, true);
+		pwmout_enable_pins(obj, true);
+	}
+
+    /* Route correct channel to location 1 */
+    PWM_TIMER->ROUTE &= ~_TIMER_ROUTE_LOCATION_MASK;
+    PWM_TIMER->ROUTE |= PWM_ROUTE;
+
+    /*HFPER is the default clock we will use. It has a frequency of 14MHz*/
+    pwm_clockfreq = REFERENCE_FREQUENCY;
+
+    /* Set default 20ms frequency and 0ms pulse width */
+    pwmout_period(obj, 0.02);
+}
+
+void pwmout_free(pwmout_t *obj) {
+	uint32_t routeloc = pwmout_get_channel_route(obj);
+	if(PWM_TIMER->ROUTE & routeloc) {
+		//This channel was in use, so disable
+		PWM_TIMER->ROUTE &= ~routeloc;
+		pwmout_enable_pins(obj, false);
+		unblockSleepMode(EM1);
+
+		//TODO: check if all channels are down, then switch off timer
+	} else {
+		//This channel was disabled already
+	}
+}
 
 void pwmout_write(pwmout_t *obj, float value)
 {
@@ -111,7 +137,7 @@ void pwmout_write(pwmout_t *obj, float value)
         value = 1;
     }
 
-    float pulse_period_in_s = obj->period_cycles / (float) clockfreq;
+    float pulse_period_in_s = obj->period_cycles / (float) pwm_clockfreq;
     pwmout_pulsewidth(obj, value * pulse_period_in_s);
 }
 
@@ -127,17 +153,17 @@ void pwmout_period(pwmout_t *obj, float seconds)
     // This gives us max resolution for a given period
 
     //The value of the top register if prescaler is set to 0
-    int cycles = clockfreq * seconds;
-    prescaler_div = 0;
+    int cycles = pwm_clockfreq * seconds;
+    pwm_prescaler_div = 0;
 
     //The top register is only 16 bits, so we keep dividing till we are below 0xFFFF
     while (cycles > 0xFFFF) {
         cycles /= 2;
-        prescaler_div++;
+        pwm_prescaler_div++;
 
-        //Max prescaler_div supported is 10
-        if (prescaler_div > 10) {
-            prescaler_div = 10;
+        //Max pwm_prescaler_div supported is 10
+        if (pwm_prescaler_div > 10) {
+            pwm_prescaler_div = 10;
             cycles = 0xFFFF; //Set it to max possible value;
             break;
         }
@@ -146,7 +172,7 @@ void pwmout_period(pwmout_t *obj, float seconds)
     obj->period_cycles = cycles;
 
     //Set prescaler
-    PWM_TIMER->CTRL = (PWM_TIMER->CTRL & ~_TIMER_CTRL_PRESC_MASK) | (prescaler_div << _TIMER_CTRL_PRESC_SHIFT);
+    PWM_TIMER->CTRL = (PWM_TIMER->CTRL & ~_TIMER_CTRL_PRESC_MASK) | (pwm_prescaler_div << _TIMER_CTRL_PRESC_SHIFT);
 
     /* Set Top Value, which controls the PWM period */
     TIMER_TopSet(PWM_TIMER, obj->period_cycles);
@@ -164,7 +190,7 @@ void pwmout_period_us(pwmout_t *obj, int us)
 
 void pwmout_pulsewidth(pwmout_t *obj, float seconds)
 {
-    obj->width_cycles = clockfreq * seconds;
+    obj->width_cycles = pwm_clockfreq * seconds;
     TIMER_CompareBufSet(PWM_TIMER, obj->channel, obj->width_cycles);
 }