pwm: Updated API

* Greater use of maa_result_t
* Added raw mode.
* Updated cycle-pwm3 to use new api.

Signed-off-by: Thomas Ingleby <thomas.c.ingleby@intel.com>

api/pwm.h

@@ -33,24 +33,49 @@ extern "C" {
 
 #include "maa.h"
 
+/**
+ * A strucutre representing a PWM pin
+ */
 typedef struct {
-    int chipid, pin;
+    /*@{*/
-    FILE *duty_fp;
+    int pin; /**< the pin number, as known to the os. */
+    int chipid; /**< the chip id, which the pwm resides */
+    FILE *duty_fp; /**< File pointer to duty file */
+    /*@}*/
 } maa_pwm_context;
 
-maa_pwm_context* maa_pwm_init(int chipin, int pin);
+/** Initialise pwm_context, uses board mapping.
+ *
+ * @param pin The PWM PIN.
+ *
+ * @return maa_pwm_context The returned initialised pwm context
+ */
+maa_pwm_context* maa_pwm_init(int pin);
+
+/** Initialise pwm_context, raw mode.
+ *
+ * @param chipid The chip inwhich the PWM is under in SYSFS
+ * @param pin The PWM PIN.
+ *
+ * @return maa_pwm_context The returned initialised pwm context
+ */
+maa_pwm_context* maa_pwm_init_raw(int chipid, int pin);
 
 /** Set the ouput duty-cycle percentage, as a float
  *
- *  @param percentage A floating-point value representing percentage of output.
+ * @param pwm The PWM context to use.
+ * @param percentage A floating-point value representing percentage of output.
  *    The value should lie between 0.0f (representing on 0%) and 1.0f
  *    Values above or below this range will be set at either 0.0f or 1.0f.
+ *
+ * @return maa_result_t the maa result.
  */
-void maa_pwm_write(maa_pwm_context* pwm, float percentage);
+maa_result_t maa_pwm_write(maa_pwm_context* pwm, float percentage);
 
 /** Read the ouput duty-cycle percentage, as a float
  *
- *  @return percentage A floating-point value representing percentage of output.
+ * @param pwm The PWM context to use.
+ * @return percentage A floating-point value representing percentage of output.
  *    The value should lie between 0.0f (representing on 0%) and 1.0f
  *    Values above or below this range will be set at either 0.0f or 1.0f.
  */
@@ -58,44 +83,75 @@ float maa_pwm_read(maa_pwm_context* pwm);
 
 /** Set the PWM period as seconds represented in a float
  *
- *  @param seconds Peroid represented as a float in seconds.
+ * @param pwm The PWM context to use.
+ * @param seconds Peroid represented as a float in seconds.
+ *
+ * @return maa_result_t the maa result.
  */
-void maa_pwm_period(maa_pwm_context* pwm, float seconds);
+maa_result_t maa_pwm_period(maa_pwm_context* pwm, float seconds);
 
 /** Set period. milli-oseconds.
- *  @param ms milli-seconds for period.
+ *
+ * @param pwm The PWM context to use.
+ * @param ms milli-seconds for period.
+ *
+ * @return maa_result_t the maa result.
  */
-void maa_pwm_period_ms(maa_pwm_context* pwm, int ms);
+maa_result_t maa_pwm_period_ms(maa_pwm_context* pwm, int ms);
 
 /** Set period. microseconds
- *  @param ns microseconds as period.
+ *
+ * @param pwm The PWM context to use.
+ * @param ns microseconds as period.
+ *
+ * @return maa_result_t the maa result.
  */
-void maa_pwm_period_us(maa_pwm_context* pwm, int us);
+maa_result_t maa_pwm_period_us(maa_pwm_context* pwm, int us);
 
 /** Set pulsewidth, As represnted by seconds in a (float).
- *  @param seconds The duration of a pulse
+ *
+ * @param pwm The PWM context to use.
+ * @param seconds The duration of a pulse
+ *
+ * @return maa_result_t the maa result.
  */
-void maa_pwm_pulsewidth(maa_pwm_context* pwm, float seconds);
+maa_result_t maa_pwm_pulsewidth(maa_pwm_context* pwm, float seconds);
 
- /** Set pulsewidth. Milliseconds
+/** Set pulsewidth. Milliseconds
- *  @param ms milliseconds for pulsewidth.
+ *
+ * @param pwm The PWM context to use.
+ * @param ms milliseconds for pulsewidth.
+ *
+ * @return maa_result_t the maa result.
  */
-void maa_pwm_pulsewidth_ms(maa_pwm_context* pwm, int ms);
+maa_result_t maa_pwm_pulsewidth_ms(maa_pwm_context* pwm, int ms);
 
-  /** Set pulsewidth, microseconds.
+/** Set pulsewidth, microseconds.
- *  @param us microseconds for pulsewidth.
+ *
+ * @param pwm The PWM context to use.
+ * @param us microseconds for pulsewidth.
+ *
+ * @return maa_result_t the maa result.
  */
-void maa_pwm_pulsewidth_us(maa_pwm_context* pwm, int us);
+maa_result_t maa_pwm_pulsewidth_us(maa_pwm_context* pwm, int us);
 
 /** Set the enable status of the PWM pin. None zero will assume on with output being driven.
  *   and 0 will disable the output.
- *  @param enable enable status of pin
+ *
+ * @param pwm The PWM context to use.
+ * @param enable enable status of pin
+ *
+ * @return maa_result_t the maa result.
  */
-void maa_pwm_enable(maa_pwm_context* pwm, int enable);
+maa_result_t maa_pwm_enable(maa_pwm_context* pwm, int enable);
 
- /** Close and unexport the PWM pin.
+/** Close and unexport the PWM pin.
+ * 
+ * @param pwm The PWM context to use.
+ *
+ * @return maa_result_t the maa result.
  */
-void maa_pwm_close(maa_pwm_context* pwm);
+maa_result_t maa_pwm_close(maa_pwm_context* pwm);
 
 #ifdef __cplusplus
 }

examples/cycle-pwm3.c

@@ -30,7 +30,7 @@ int
 main ()
 {
     maa_pwm_context* pwm;
-    pwm = maa_pwm_init(0, 3);
+    pwm = maa_pwm_init(3);
     if (pwm == NULL) {
         return 1;
     }

src/pwm/pwm.c

@@ -38,7 +38,7 @@ maa_pwm_setup_duty_fp(maa_pwm_context* dev)
     return 0;
 }
 
-static void
+static maa_result_t
 maa_pwm_write_period(maa_pwm_context* dev, int period)
 {
     FILE *period_f;
@@ -47,12 +47,16 @@ maa_pwm_write_period(maa_pwm_context* dev, int period)
 
     if ((period_f = fopen(bu, "r+b")) == NULL) {
         fprintf(stderr, "Failed to open period for writing!\n");
+        return MAA_ERROR_INVALID_RESOURCE;
     }
     fprintf(period_f, "%d", period);
     fclose(period_f);
+    if (ferror(period_f) != 0)
+        return MAA_ERROR_INVALID_RESOURCE;
+    return MAA_SUCCESS;
 }
 
-static void
+static maa_result_t
 maa_pwm_write_duty(maa_pwm_context* dev, int duty)
 {
     if (dev->duty_fp == NULL) {
@@ -61,6 +65,9 @@ maa_pwm_write_duty(maa_pwm_context* dev, int duty)
     fprintf(dev->duty_fp, "%d", duty);
     rewind(dev->duty_fp);
     fflush(dev->duty_fp);
+     if (ferror(dev->duty_fp) != 0)
+        return MAA_ERROR_INVALID_RESOURCE;
+    return MAA_SUCCESS;
 }
 
 static int
@@ -93,7 +100,13 @@ maa_pwm_get_duty(maa_pwm_context* dev)
 }
 
 maa_pwm_context*
-maa_pwm_init(int chipin, int pin)
+maa_pwm_init(int pin) {
+    //TODO
+    return maa_pwm_init_raw(0, pin);
+}
+
+maa_pwm_context*
+maa_pwm_init_raw(int chipin, int pin)
 {
     maa_pwm_context* dev = (maa_pwm_context*) malloc(sizeof(maa_pwm_context));
     if (dev == NULL)
@@ -118,10 +131,10 @@ maa_pwm_init(int chipin, int pin)
     return dev;
 }
 
-void
+maa_result_t
 maa_pwm_write(maa_pwm_context* dev, float percentage)
 {
-    maa_pwm_write_duty(dev, percentage * maa_pwm_get_period(dev));
+   return maa_pwm_write_duty(dev, percentage * maa_pwm_get_period(dev));
 }
 
 float
@@ -131,43 +144,43 @@ maa_pwm_read(maa_pwm_context* dev)
     return output;
 }
 
-void
+maa_result_t
 maa_pwm_period(maa_pwm_context* dev, float seconds)
 {
-    maa_pwm_period_ms(dev, seconds*1000);
+    return maa_pwm_period_ms(dev, seconds*1000);
 }
 
-void
+maa_result_t
 maa_pwm_period_ms(maa_pwm_context* dev, int ms)
 {
-    maa_pwm_period_us(dev, ms*1000);
+    return maa_pwm_period_us(dev, ms*1000);
 }
 
-void
+maa_result_t
 maa_pwm_period_us(maa_pwm_context* dev, int us)
 {
-    maa_pwm_write_period(dev, us*1000);
+    return maa_pwm_write_period(dev, us*1000);
 }
 
-void
+maa_result_t
 maa_pwm_pulsewidth(maa_pwm_context* dev, float seconds)
 {
-    maa_pwm_pulsewidth_ms(dev, seconds*1000);
+    return maa_pwm_pulsewidth_ms(dev, seconds*1000);
 }
 
-void
+maa_result_t
 maa_pwm_pulsewidth_ms(maa_pwm_context* dev, int ms)
 {
-    maa_pwm_pulsewidth_us(dev, ms*1000);
+    return maa_pwm_pulsewidth_us(dev, ms*1000);
 }
 
-void
+maa_result_t
 maa_pwm_pulsewidth_us(maa_pwm_context* dev, int us)
 {
-    maa_pwm_write_duty(dev, us*1000);
+    return maa_pwm_write_duty(dev, us*1000);
 }
 
-void
+maa_result_t
 maa_pwm_enable(maa_pwm_context* dev, int enable)
 {
     int status;
@@ -181,15 +194,17 @@ maa_pwm_enable(maa_pwm_context* dev, int enable)
     sprintf(bu, "/sys/class/pwm/pwmchip%d/pwm%d/enable", dev->chipid, dev->pin);
 
     if ((enable_f = fopen(bu, "w")) == NULL) {
-        fprintf(stderr, "Failed to open export for writing!\n");
+        fprintf(stderr, "Failed to open enable for writing!\n");
-    } else {
+        return MAA_ERROR_INVALID_RESOURCE;
-        fprintf(enable_f, "%d", status);
-        fclose(enable_f);
     }
-    //Do Something
+    fprintf(enable_f, "%d", status);
+    fclose(enable_f);
+    if (ferror(enable_f) != 0)
+        return MAA_ERROR_INVALID_RESOURCE;
+    return MAA_SUCCESS;
 }
 
-void
+maa_result_t
 maa_pwm_close(maa_pwm_context* dev)
 {
     maa_pwm_enable(dev, 0);
@@ -199,9 +214,12 @@ maa_pwm_close(maa_pwm_context* dev)
 
     if ((unexport_f = fopen(buffer, "w")) == NULL) {
         fprintf(stderr, "Failed to open unexport for writing!\n");
-    } else {
+        return MAA_ERROR_INVALID_RESOURCE;
-        fprintf(unexport_f, "%d", dev->pin);
-        fclose(unexport_f);
     }
+    fprintf(unexport_f, "%d", dev->pin);
+    fclose(unexport_f);
     free(dev);
+    if (ferror(unexport_f) != 0)
+        return MAA_ERROR_INVALID_RESOURCE;
+    return MAA_SUCCESS;
 }