drivers/soft_onewire: add soft onewire driver

Author: Enoch247

drivers/include/soft_onewire.h

@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2023 Prime Controls
+ *
+ * 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.
+ */
+
+/**
+ * @defgroup    drivers_soft_onewire Soft 1-Wire Bus Driver
+ * @ingroup     drivers_onewire
+ * @ingroup     drivers_soft_periph
+ * @brief       Software implemented 1-Wire bus master
+ *
+ * This is a soft driver implementation of a 1-Wire bus master. Minimally, the
+ * only required hardware is a GPIO pin.
+ *
+ * The pseudomodule `soft_onewire_hwtimer` is provided. When enabled, the driver
+ * will use a dedicated `periph_timer` rather than `ztimer` to manage time
+ * critical bus operations.
+ *
+ * @{
+ * @file
+ * @brief       1-Wire driver interface
+ *
+ * @author      Joshua DeWeese <[email protected]>
+ */
+
+#ifndef SOFT_ONEWIRE_H
+#define SOFT_ONEWIRE_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "mutex.h"
+#include "onewire.h"
+#include "periph/gpio.h"
+#include "periph/timer.h"
+#include "ztimer.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct soft_onewire_t soft_onewire_t;
+
+/** timer callback function signature internally used to schedule events */
+typedef void (*soft_onewire_timer_cb_t)(soft_onewire_t*);
+
+/**
+ * @brief   Soft 1-Wire configuration parameters
+ */
+typedef struct {
+    gpio_t pin;                 /**< GPIO pin the bus is connected to */
+    gpio_mode_t pin_imode;      /**< GPIO pin input mode */
+#ifdef MODULE_SOFT_ONEWIRE_HWTIMER
+    tim_t timer;                /**< peripherial timer that driver should use */
+#endif
+} soft_onewire_params_t;
+
+/**
+ * @brief   Soft 1-Wire bus device descriptor
+ */
+struct soft_onewire_t {
+    /** devices's configuration params */
+    const soft_onewire_params_t *params;
+
+    /** mutext to sync thread with ISRs */
+    mutex_t sync;
+
+    /** TODO: rm or doc */
+    uint8_t mask;
+
+    /** Pointer to transmit and receive buffers. Only one at a time will be
+        used, so they are in a union to save RAM. */
+    union {
+        const uint8_t *tx_buf;  /**< pointer to buffer of bits to send */
+        uint8_t *rx_buf;        /**< pointer to buffer for received bits */
+    };
+
+    /** number of bits to send or receive, also used to return errors from
+        ISR */
+    int buf_size;
+
+#ifdef MODULE_SOFT_ONEWIRE_HWTIMER
+
+    /** pointer to callback of next bus event */
+    soft_onewire_timer_cb_t timer_cb;
+#else
+    /** timer used to trigger bus events */
+    ztimer_t timer;
+#endif
+};
+
+/** onewire driver callbacks for soft_onewire implementation */
+extern const onewire_driver_t soft_onewire_driver;
+
+#endif /* SOFT_ONEWIRE_H */
+/** @} */

drivers/soft_onewire/Makefile

@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base

drivers/soft_onewire/Makefile.dep

@@ -0,0 +1,11 @@
+FEATURES_REQUIRED += periph_gpio
+
+ifneq (,$(filter soft_onewire_hwtimer,$(USEMODULE)))
+  FEATURES_REQUIRED += periph_timer
+else
+  # this is needed to get ztimer accurate enough for use in this application
+  DEFAULT_MODULE += ztimer_auto_adjust
+
+  USEMODULE += ztimer
+  USEMODULE += ztimer_usec
+endif

drivers/soft_onewire/Makefile.include

@@ -0,0 +1,2 @@
+USEMODULE_INCLUDES_soft_onewire := $(LAST_MAKEFILEDIR)/include
+USEMODULE_INCLUDES += $(USEMODULE_INCLUDES_soft_onewire)

drivers/soft_onewire/include/soft_onewire_params.h

@@ -0,0 +1,39 @@
+#ifndef SOFT_ONEWIRE_PARAMS_H
+
+#include "board.h"
+
+#include "container.h"
+#include "soft_onewire.h"
+
+#ifndef SOFT_ONEWIRE_PARAMS_PIN
+#define SOFT_ONEWIRE_PARAMS_PIN GPIO_UNDEF
+#endif
+
+#ifndef SOFT_ONEWIRE_PARAMS_PIN_IMODE
+#define SOFT_ONEWIRE_PARAMS_PIN_IMODE GPIO_IN_PU
+#endif
+
+#ifndef SOFT_ONEWIRE_PARAMS_HWTIMER
+#define SOFT_ONEWIRE_PARAMS_HWTIMER TIMER_UNDEF
+#endif
+
+#ifdef MODULE_SOFT_ONEWIRE_HWTIMER
+#define SOFT_ONEWIRE_PARAMS_HWTIMER_ .timer = SOFT_ONEWIRE_PARAMS_HWTIMER,
+#endif
+
+#ifndef SOFT_ONEWIRE_PARAMS
+#define SOFT_ONEWIRE_PARAMS \
+    { \
+        .pin = SOFT_ONEWIRE_PARAMS_PIN, \
+        .pin_imode = SOFT_ONEWIRE_PARAMS_PIN_IMODE, \
+        SOFT_ONEWIRE_PARAMS_HWTIMER_ \
+    }
+#endif
+
+static const soft_onewire_params_t soft_onewire_params[] = {
+    SOFT_ONEWIRE_PARAMS
+};
+
+#define SOFT_ONEWIRE_NUMOF ARRAY_SIZE(soft_onewire_params)
+
+#endif