saul/gpio: add support to initialized state

drivers/include/saul/periph.h

@@ -34,8 +34,8 @@ extern "C" {
 #ifdef MODULE_SAUL_GPIO
 typedef enum {
     SAUL_GPIO_INVERTED   = (1 << 0),  /**< pin is used as inverted */
-    SAUL_GPIO_INIT_CLEAR = 1 << 1, /**< set pin inactive after initialization */
-    SAUL_GPIO_INIT_SET   = 1 << 2, /**< set pin active after initialization */
+    SAUL_GPIO_INIT_CLEAR = (1 << 1),  /**< set pin inactive after init */
+    SAUL_GPIO_INIT_SET   = (1 << 2),  /**< set pin active after init */
 } saul_gpio_flags_t;
 
 /**

sys/auto_init/saul/auto_init_gpio.c

@@ -66,6 +66,12 @@ void auto_init_gpio(void)
         }
         /* initialize the GPIO pin */
         gpio_init(p->pin, p->mode);
+        /* set initial pin state if configured */
+        if (p->flags & (SAUL_GPIO_INIT_CLEAR | SAUL_GPIO_INIT_SET)) {
+            phydat_t s;
+            s.val[0] = (p->flags & SAUL_GPIO_INIT_SET);
+            saul_reg_entries[i].driver->write(p, &s);
+        }
         /* add to registry */
         saul_reg_add(&(saul_reg_entries[i]));
     }