Merge pull request #4847 from haukepetersen/add_samr21_3rdpwm

boards/samr21-xpro: added third channel for PWM1

boards/samr21-xpro/include/periph_conf.h

@@ -122,7 +122,7 @@ static const uart_conf_t uart_config[] = {
  */
 #define PWM_0_EN            1
 #define PWM_1_EN            1
-#define PWM_MAX_CHANNELS    2
+#define PWM_MAX_CHANNELS    3
 /* for compatibility with test application */
 #define PWM_0_CHANNELS      PWM_MAX_CHANNELS
 #define PWM_1_CHANNELS      PWM_MAX_CHANNELS
@@ -132,16 +132,18 @@ static const pwm_conf_t pwm_config[] = {
 #if PWM_0_EN
     {TCC1, {
         /* GPIO pin, MUX value, TCC channel */
-        {GPIO_PIN(PA, 6), GPIO_MUX_E, 0},
-        {GPIO_PIN(PA, 7), GPIO_MUX_E, 1}
+        { GPIO_PIN(PA, 6), GPIO_MUX_E, 0 },
+        { GPIO_PIN(PA, 7), GPIO_MUX_E, 1 },
+        { GPIO_UNDEF, (gpio_mux_t)0, 2 }
     }},
 #endif
 #if PWM_1_EN
     {TCC0, {
         /* GPIO pin, MUX value, TCC channel */
-        {GPIO_PIN(PA, 18), GPIO_MUX_F, 2},
-        {GPIO_PIN(PA, 19), GPIO_MUX_F, 3}
-    }},
+        { GPIO_PIN(PA, 16), GPIO_MUX_F, 0 },
+        { GPIO_PIN(PA, 18), GPIO_MUX_F, 2 },
+        { GPIO_PIN(PA, 19), GPIO_MUX_F, 3 }
+    }}
 #endif
 };
 

cpu/samd21/include/periph_cpu.h

@@ -48,7 +48,7 @@ typedef struct {
  */
 typedef struct {
     Tcc *dev;                   /**< TCC device to use */
-    pwm_conf_chan_t chan[2];    /**< channel configuration */
+    pwm_conf_chan_t chan[3];    /**< channel configuration */
 } pwm_conf_t;
 
 /**

cpu/samd21/periph/pwm.c

@@ -106,8 +106,10 @@ uint32_t pwm_init(pwm_t dev, pwm_mode_t mode, uint32_t freq, uint16_t res)
 
     /* configure the used pins */
     for (int i = 0; i < PWM_MAX_CHANNELS; i++) {
-        gpio_init(pwm_config[dev].chan[i].pin, GPIO_DIR_OUT, GPIO_NOPULL);
-        gpio_init_mux(pwm_config[dev].chan[i].pin, pwm_config[dev].chan[i].mux);
+        if (pwm_config[dev].chan[i].pin != GPIO_UNDEF) {
+            gpio_init(pwm_config[dev].chan[i].pin, GPIO_DIR_OUT, GPIO_NOPULL);
+            gpio_init_mux(pwm_config[dev].chan[i].pin, pwm_config[dev].chan[i].mux);
+        }
     }
 
     /* power on the device */
@@ -152,7 +154,8 @@ uint8_t pwm_channels(pwm_t dev)
 
 void pwm_set(pwm_t dev, uint8_t channel, uint16_t value)
 {
-    if (channel >= PWM_MAX_CHANNELS) {
+    if ((channel >= PWM_MAX_CHANNELS) ||
+        (pwm_config[dev].chan[channel].pin == GPIO_UNDEF)) {
         return;
     }
     _tcc(dev)->CC[_chan(dev, channel)].reg = value;