Fix pwm out resets after suspend

UNITTESTS/stubs/pwmout_api_stub.c

@@ -51,6 +51,11 @@ void pwmout_period_us(pwmout_t *obj, int us)
 {
 }
 
+int pwmout_read_period_us(pwmout_t *obj)
+{
+    return 0;
+}
+
 void pwmout_pulsewidth(pwmout_t *obj, float seconds)
 {
 }
@@ -63,4 +68,9 @@ void pwmout_pulsewidth_us(pwmout_t *obj, int us)
 {
 }
 
+int pwmout_read_pulsewidth_us(pwmout_t *obj)
+{
+    return 0;
+}
+
 #endif // DEVICE_PWMOUT

drivers/include/drivers/PwmOut.h

@@ -110,6 +110,12 @@ class PwmOut {
      */
     void period_us(int us);
 
+    /** Read the PWM period
+     *  @returns
+     *   The PWM period, specified in microseconds (int)
+     */
+    int read_period_us();
+
     /** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
      *  @param seconds Change the pulse width of a PWM signal specified in seconds (float)
      */
@@ -125,6 +131,12 @@ class PwmOut {
      */
     void pulsewidth_us(int us);
 
+    /** Read the PWM pulsewidth
+     *  @returns
+     *   The PWM pulsewith, specified in microseconds (int)
+     */
+    int read_pulsewitdth_us();
+
     /** Suspend PWM operation
      *
      * Control the PWM state. This is primarily intended
@@ -191,6 +203,7 @@ class PwmOut {
     bool _deep_sleep_locked;
     bool _initialized;
     float _duty_cycle;
+    int _period_us;
 #endif
 };
 

drivers/source/PwmOut.cpp

@@ -30,7 +30,8 @@ PwmOut::PwmOut(PinName pin) :
     _pin(pin),
     _deep_sleep_locked(false),
     _initialized(false),
-    _duty_cycle(0)
+    _duty_cycle(0),
+    _period_us(0)
 {
     PwmOut::init();
 }
@@ -83,6 +84,14 @@ void PwmOut::period_us(int us)
     core_util_critical_section_exit();
 }
 
+int PwmOut::read_period_us()
+{
+    core_util_critical_section_enter();
+    auto val = pwmout_read_period_us(&_pwm);
+    core_util_critical_section_exit();
+    return val;
+}
+
 void PwmOut::pulsewidth(float seconds)
 {
     core_util_critical_section_enter();
@@ -104,11 +113,20 @@ void PwmOut::pulsewidth_us(int us)
     core_util_critical_section_exit();
 }
 
+int PwmOut::read_pulsewitdth_us()
+{
+    core_util_critical_section_enter();
+    auto val = pwmout_read_pulsewidth_us(&_pwm);
+    core_util_critical_section_exit();
+    return val;
+}
+
 void PwmOut::suspend()
 {
     core_util_critical_section_enter();
     if (_initialized) {
         _duty_cycle = PwmOut::read();
+        _period_us = PwmOut::read_period_us();
         PwmOut::deinit();
     }
     core_util_critical_section_exit();
@@ -120,6 +138,7 @@ void PwmOut::resume()
     if (!_initialized) {
         PwmOut::init();
         PwmOut::write(_duty_cycle);
+        PwmOut::period_us(_period_us);
     }
     core_util_critical_section_exit();
 }

hal/include/hal/pwmout_api.h

@@ -44,9 +44,11 @@ typedef struct pwmout_s pwmout_t;
  * * ::pwmout_period sets the PWM period specified in seconds, keeping the duty cycle the same
  * * ::pwmout_period_ms sets the PWM period specified in miliseconds, keeping the duty cycle the same
  * * ::pwmout_period_us sets the PWM period specified in microseconds, keeping the duty cycle the same
+ * * ::pwmout_read_period_us reads the PWM period specified in microseconds
  * * ::pwmout_pulsewidth sets the PWM pulsewidth specified in seconds, keeping the period the same
  * * ::pwmout_pulsewidth_ms sets the PWM pulsewidth specified in miliseconds, keeping the period the same
  * * ::pwmout_pulsewidth_us sets the PWM pulsewidth specified in microseconds, keeping the period the same
+ * * ::pwmout_read_pulsewidth_us read the PWM pulsewidth specified in microseconds
  * * The accuracy of the PWM is +/- 10%
  * * The PWM operations ::pwmout_write, ::pwmout_read, ::pwmout_read, ::pwmout_period_ms, ::pwmout_period_us
  *   ::pwmout_pulsewidth, ::pwmout_pulsewidth_ms, ::pwmout_pulsewidth_us take less than 20us to complete
@@ -125,6 +127,13 @@ void pwmout_period_ms(pwmout_t *obj, int ms);
  */
 void pwmout_period_us(pwmout_t *obj, int us);
 
+/** Read the PWM period specified in microseconds
+ *
+ * @param obj The pwmout object
+ * @return A int output period
+ */
+int pwmout_read_period_us(pwmout_t *obj);
+
 /** Set the PWM pulsewidth specified in seconds, keeping the period the same.
  *
  * @param obj     The pwmout object
@@ -146,6 +155,13 @@ void pwmout_pulsewidth_ms(pwmout_t *obj, int ms);
  */
 void pwmout_pulsewidth_us(pwmout_t *obj, int us);
 
+/** Read the PWM pulsewidth specified in microseconds
+ *
+ * @param obj The pwmout object
+ * @return A int output pulsewitdth
+ */
+int pwmout_read_pulsewidth_us(pwmout_t *obj);
+
 /** Get the pins that support PWM
  *
  * Return a PinMap array of pins that support PWM.

targets/TARGET_Cypress/TARGET_PSOC6/cy_pwmout_api.c

@@ -74,6 +74,11 @@ void pwmout_period_us(pwmout_t *obj, int us)
     }
 }
 
+int pwmout_read_period_us(pwmout_t *obj)
+{
+    return obj->period_us;
+}
+
 void pwmout_pulsewidth(pwmout_t *obj, float seconds)
 {
     pwmout_pulsewidth_us(obj, (int)(seconds * CY_US_PER_SECOND));
@@ -92,6 +97,11 @@ void pwmout_pulsewidth_us(pwmout_t *obj, int us)
     }
 }
 
+int pwmout_read_pulsewidth_us(pwmout_t *obj)
+{
+    return obj->width_us;
+}
+
 const PinMap *pwmout_pinmap(void)
 {
     return PinMap_PWM_OUT;

targets/TARGET_Freescale/TARGET_K20XX/pwmout_api.c

@@ -22,7 +22,8 @@
 
 static float pwm_clock = 0;
 
-void pwmout_init(pwmout_t* obj, PinName pin) {
+void pwmout_init(pwmout_t *obj, PinName pin)
+{
     // determine the channel
     PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
     MBED_ASSERT(pwm != (PWMName)NC);
@@ -36,8 +37,9 @@ void pwmout_init(pwmout_t* obj, PinName pin) {
     while (clkval > 1) {
         clkdiv++;
         clkval /= 2.0;
-        if (clkdiv == 7)
+        if (clkdiv == 7) {
             break;
+        }
     }
 
     pwm_clock = clkval;
@@ -53,7 +55,7 @@ void pwmout_init(pwmout_t* obj, PinName pin) {
     ftm->MODE = FTM_MODE_FTMEN_MASK;
     ftm->SYNC = FTM_SYNC_CNTMIN_MASK;
     ftm->SYNCONF = FTM_SYNCONF_SYNCMODE_MASK | FTM_SYNCONF_SWSOC_MASK | FTM_SYNCONF_SWWRBUF_MASK;
-    
+
     //Without SYNCEN set CnV does not seem to update
     ftm->COMBINE = FTM_COMBINE_SYNCEN0_MASK | FTM_COMBINE_SYNCEN1_MASK | FTM_COMBINE_SYNCEN2_MASK | FTM_COMBINE_SYNCEN3_MASK;
 
@@ -64,60 +66,86 @@ void pwmout_init(pwmout_t* obj, PinName pin) {
     // default to 20ms: standard for servos, and fine for e.g. brightness control
     pwmout_period_ms(obj, 20);
     pwmout_write(obj, 0.0);
-    
+
     // Wire pinout
     pinmap_pinout(pin, PinMap_PWM);
 }
 
-void pwmout_free(pwmout_t* obj) {}
+void pwmout_free(pwmout_t *obj) {}
 
-void pwmout_write(pwmout_t* obj, float value) {
+void pwmout_write(pwmout_t *obj, float value)
+{
     if (value < 0.0) {
         value = 0.0;
     } else if (value > 1.0) {
         value = 1.0;
     }
-    
-    while(*obj->SYNC & FTM_SYNC_SWSYNC_MASK);
+
+    while (*obj->SYNC & FTM_SYNC_SWSYNC_MASK);
     *obj->CnV = (uint32_t)((float)(*obj->MOD + 1) * value);
-    *obj->SYNC |= FTM_SYNC_SWSYNC_MASK;    
+    *obj->SYNC |= FTM_SYNC_SWSYNC_MASK;
 }
 
-float pwmout_read(pwmout_t* obj) {
-    while(*obj->SYNC & FTM_SYNC_SWSYNC_MASK);
+float pwmout_read(pwmout_t *obj)
+{
+    while (*obj->SYNC & FTM_SYNC_SWSYNC_MASK);
     float v = (float)(*obj->CnV) / (float)(*obj->MOD + 1);
     return (v > 1.0) ? (1.0) : (v);
 }
 
-void pwmout_period(pwmout_t* obj, float seconds) {
+void pwmout_period(pwmout_t *obj, float seconds)
+{
     pwmout_period_us(obj, seconds * 1000000.0f);
 }
 
-void pwmout_period_ms(pwmout_t* obj, int ms) {
+void pwmout_period_ms(pwmout_t *obj, int ms)
+{
     pwmout_period_us(obj, ms * 1000);
 }
 
 // Set the PWM period, keeping the duty cycle the same.
-void pwmout_period_us(pwmout_t* obj, int us) {
+void pwmout_period_us(pwmout_t *obj, int us)
+{
     float dc = pwmout_read(obj);
     *obj->MOD = (uint32_t)(pwm_clock * (float)us) - 1;
     *obj->SYNC |= FTM_SYNC_SWSYNC_MASK;
     pwmout_write(obj, dc);
 }
 
-void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
+int pwmout_read_period_us(pwmout_t *obj)
+{
+    uint32_t pwm_period = 0;
+    if (pwm_clock > 0) {
+        pwm_period = ((*obj->MOD) + 1) / pwm_clock;
+    }
+    return pwm_period;
+}
+
+void pwmout_pulsewidth(pwmout_t *obj, float seconds)
+{
     pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
 }
 
-void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
+void pwmout_pulsewidth_ms(pwmout_t *obj, int ms)
+{
     pwmout_pulsewidth_us(obj, ms * 1000);
 }
 
-void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
+void pwmout_pulsewidth_us(pwmout_t *obj, int us)
+{
     *obj->CnV = (uint32_t)(pwm_clock * (float)us);
     *obj->SYNC |= FTM_SYNC_SWSYNC_MASK;
 }
 
+int pwmout_read_pulsewidth_us(pwmout_t *obj)
+{
+    uint32_t pwm_pulsewidth = 0;
+    if (pwm_clock > 0) {
+        pwm_pulsewidth = (*obj->CnV) / pwm_clock;
+    }
+    return pwm_pulsewidth;
+}
+
 const PinMap *pwmout_pinmap()
 {
     return PinMap_PWM;