nrf5x_common: Add qdec peripheral implementation

cpu/nrf5x_common/include/periph_cpu_common.h

@@ -188,6 +188,17 @@ typedef enum {
 #define NWDT_TIME_UPPER_LIMIT          ((UINT32_MAX >> 15) * US_PER_MS + 1)
 /** @} */
 
+/**
+ * @brief Quadrature decoder configuration struct
+ */
+typedef struct {
+    gpio_t a_pin;          /**< GPIO Pin for phase A */
+    gpio_t b_pin;          /**< GPIO Pin for phase B */
+    gpio_t led_pin;        /**< LED GPIO, GPIO_UNDEF to disable */
+    uint8_t sample_period; /**< Sample period used, e.g. QDEC_SAMPLEPER_SAMPLEPER_128us */
+    bool debounce_filter;  /**< Enable/disable debounce filter */
+} qdec_conf_t;
+
 /**
  * @brief Retrieve the exti(GPIOTE) channel associated with a gpio
  *

cpu/nrf5x_common/periph/qdec.c

@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2021 Koen Zandberg <koen@bergzand.net>
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     cpu_nrf5x_common
+ * @ingroup     drivers_periph_qdec
+ * @{
+ *
+ * @file
+ * @brief       Low-level QDEC driver implementation
+ *
+ * @author      Koen Zandberg <koen@bergzand.net>
+ *
+ * @}
+ */
+#include <errno.h>
+
+#include "cpu.h"
+#include "periph_conf.h"
+#include "periph/qdec.h"
+#include "periph/gpio.h"
+
+#ifdef QDEC_NUMOF
+
+
+/**
+ * @brief   Interrupt context for each configured qdec
+ */
+static qdec_isr_ctx_t isr_ctx[QDEC_NUMOF];
+
+static inline NRF_QDEC_Type* dev(qdec_t qdec)
+{
+    (void)qdec;
+    return NRF_QDEC;
+}
+
+static inline const qdec_conf_t* conf(qdec_t qdec)
+{
+    return &qdec_config[qdec];
+}
+
+int32_t qdec_init(qdec_t qdec, qdec_mode_t mode, qdec_cb_t cb, void *arg)
+{
+    (void)mode;
+    /* Verify parameters */
+    assert((qdec < QDEC_NUMOF));
+
+    /* The nrf5x peripheral counts all edges */
+    if (mode != QDEC_X4) {
+        return -EINVAL;
+    }
+
+    isr_ctx[qdec].cb = cb;
+    isr_ctx[qdec].arg = arg;
+
+    if (cb) {
+        NVIC_EnableIRQ(QDEC_IRQn);
+        dev(qdec)->INTENSET = QDEC_INTENSET_ACCOF_Msk;
+    }
+    else {
+        NVIC_DisableIRQ(QDEC_IRQn);
+        dev(qdec)->INTENCLR = QDEC_INTENCLR_ACCOF_Msk;
+    }
+
+    gpio_init(conf(qdec)->a_pin, GPIO_IN_PU);
+    gpio_init(conf(qdec)->b_pin, GPIO_IN_PU);
+
+    dev(qdec)->PSEL.A = conf(qdec)->a_pin;
+    dev(qdec)->PSEL.B = conf(qdec)->b_pin;
+
+    /** Optionally set or disable the LED */
+    dev(qdec)->PSEL.LED = gpio_is_valid(conf(qdec)->led_pin)
+        ? QDEC_PSEL_LED_CONNECT_Msk
+        : conf(qdec)->led_pin;
+
+    dev(qdec)->DBFEN = conf(qdec)->debounce_filter ? 1 : 0;
+
+    /* Enable the peripheral */
+    dev(qdec)->ENABLE = 1;
+    dev(qdec)->TASKS_START = 1;
+    return 0;
+}
+
+int32_t qdec_read_and_reset(qdec_t qdec)
+{
+    /* Read and clear ACC register */
+    dev(qdec)->TASKS_RDCLRACC = 1;
+    return dev(qdec)->ACCREAD;
+}
+
+int32_t qdec_read(qdec_t qdec)
+{
+    return dev(qdec)->ACC;
+}
+
+void qdec_start(qdec_t qdec)
+{
+    dev(qdec)->TASKS_START = 1;
+}
+
+void qdec_stop(qdec_t qdec)
+{
+    dev(qdec)->TASKS_STOP = 1;
+    while (dev(qdec)->EVENTS_STOPPED == 0) {}
+    dev(qdec)->EVENTS_STOPPED = 0;
+}
+
+void isr_qdec(void)
+{
+    qdec_t qdec = QDEC_DEV(0); /* only one available */
+    dev(qdec)->EVENTS_ACCOF = 0;
+    isr_ctx[qdec].cb(isr_ctx[qdec].arg);
+}
+#endif