drivers: add at24mac driver

The AT24MAC is an EEPROM that provides unique ID functionality.
On one address it provides normal AT24xxx EEPROM operations, but
on a seperate i2c address a read-only EUI-64 and a 128-bit ID are
provided.

This adds a simply driver for this chip.

drivers/Makefile.dep

@@ -36,6 +36,10 @@ ifneq (,$(filter at,$(USEMODULE)))
   USEMODULE += isrpipe_read_timeout
 endif
 
+ifneq (,$(filter at24mac,$(USEMODULE)))
+  FEATURES_REQUIRED += periph_i2c
+endif
+
 ifneq (,$(filter at30tse75x,$(USEMODULE)))
   USEMODULE += xtimer
   FEATURES_REQUIRED += periph_i2c

drivers/Makefile.include

@@ -20,6 +20,10 @@ ifneq (,$(filter apa102,$(USEMODULE)))
   USEMODULE_INCLUDES += $(RIOTBASE)/drivers/apa102/include
 endif
 
+ifneq (,$(filter at24mac,$(USEMODULE)))
+  USEMODULE_INCLUDES += $(RIOTBASE)/drivers/at24mac/include
+endif
+
 ifneq (,$(filter at86rf2xx,$(USEMODULE)))
   USEMODULE_INCLUDES += $(RIOTBASE)/drivers/at86rf2xx/include
 endif

drivers/at24mac/Makefile

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

drivers/at24mac/at24mac.c

@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2019 Benjamin Valentin
+ *
+ * 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     drivers_at24mac
+ *
+ * @{
+ * @file
+ * @brief       Driver for AT24MAC unique ID chip.
+ *
+ * @author      Benjamin Valentin <benjamin.valentin@ml-pa.com>
+ *
+ * @}
+ */
+
+#include <errno.h>
+
+#include "at24mac.h"
+#include "at24mac_params.h"
+
+#define CMD_READ_EUI48      (0x9A)
+#define CMD_READ_EUI64      (0x98)
+#define CMD_READ_ID128      (0x80)
+
+static bool _is_valid(at24mac_type_t type, uint8_t reg)
+{
+    if (type == AT24MAC4XX && reg == CMD_READ_EUI64) {
+        return false;
+    }
+
+    if (type == AT24MAC6XX && reg == CMD_READ_EUI48) {
+        return false;
+    }
+
+    return true;
+}
+
+static int _read_reg(at24mac_t dev, uint8_t reg, void *dst, size_t size)
+{
+    if (dev >= ARRAY_SIZE(at24mac_params)) {
+        return -ERANGE;
+    }
+
+    int res = 0;
+    const at24mac_params_t *params = &at24mac_params[dev];
+
+    if (!_is_valid(params->type, reg)) {
+        return -ENOTSUP;
+    }
+
+    res = i2c_acquire(params->i2c_dev);
+    if (res) {
+        return res;
+    }
+
+    res = i2c_read_regs(params->i2c_dev, params->i2c_addr,
+                        reg, dst, size, 0);
+
+    i2c_release(params->i2c_dev);
+
+    return res;
+}
+
+int at24mac_get_eui48(at24mac_t dev, eui48_t *dst)
+{
+    return _read_reg(dev, CMD_READ_EUI48, dst, sizeof(*dst));
+}
+
+int at24mac_get_eui64(at24mac_t dev, eui64_t *dst)
+{
+    return _read_reg(dev, CMD_READ_EUI64, dst, sizeof(*dst));
+}
+
+int at24mac_get_id128(at24mac_t dev, void *dst)
+{
+    return _read_reg(dev, CMD_READ_ID128, dst, AT24MAC_ID_LEN);
+}
+
+at24mac_type_t at24mac_get_type(at24mac_t dev)
+{
+    if (dev >= ARRAY_SIZE(at24mac_params)) {
+        return -ERANGE;
+    }
+
+    return at24mac_params[dev].type;
+}

drivers/at24mac/include/at24mac_params.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2019 Benjamin Valentin
+ *
+ * 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     drivers_at24mac
+ *
+ * @{
+ * @file
+ * @brief       Default configuration for the AT24MAC chip
+ *
+ * @author      Benjamin Valentin <benjamin.valentin@ml-pa.com>
+ */
+
+#ifndef AT24MAC_PARAMS_H
+#define AT24MAC_PARAMS_H
+
+#include "board.h"
+#include "at24mac.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @name    Set default configuration parameters for AT24Mac driver
+ * @{
+ */
+#ifndef AT24MAC_PARAM_I2C_DEV
+#define AT24MAC_PARAM_I2C_DEV       I2C_DEV(0)
+#endif
+#ifndef AT24MAC_PARAM_I2C_ADDR
+#define AT24MAC_PARAM_I2C_ADDR      (0x58)
+#endif
+#ifndef AT24MAC_PARAM_TYPE
+#define AT24MAC_PARAM_TYPE          (AT24MAC6XX)
+#endif
+
+#ifndef AT24MAC_PARAMS
+#define AT24MAC_PARAMS              { .i2c_dev      = AT24MAC_PARAM_I2C_DEV, \
+                                      .i2c_addr     = AT24MAC_PARAM_I2C_ADDR,\
+                                      .type         = AT24MAC_PARAM_TYPE     }
+#endif
+/**@}*/
+
+/**
+ * @brief   Configuration for AT24MACs
+ */
+static const at24mac_params_t at24mac_params[] =
+{
+    AT24MAC_PARAMS
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AT24MAC_PARAMS_H */
+/** @} */

drivers/include/at24mac.h

@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2019 Benjamin Valentin
+ *
+ * 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_at24mac unique ID chip
+ * @brief       Device driver interface for the AT24MAC I2C chip
+ * @{
+ *
+ * @file
+ *
+ * @author      Benjamin Valentin <benjamin.valentin@ml-pa.com>
+ */
+
+#ifndef AT24MAC_H
+#define AT24MAC_H
+
+#include <stdint.h>
+#include "net/eui48.h"
+#include "net/eui64.h"
+#include "periph/i2c.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Device handle type for AT24Mac devices
+ */
+typedef uint_fast8_t at24mac_t;
+
+#define AT24MAC_ID_LEN  (16)            /**< Length of ID128 */
+
+/**
+ * @brief   Type of the AT24Mac device
+ */
+typedef enum {
+    AT24MAC4XX,                         /**< provides EUI-48 */
+    AT24MAC6XX                          /**< provides EUI-64 */
+} at24mac_type_t;
+
+/**
+ * @brief   struct holding all params needed for device communication
+ */
+typedef struct {
+    i2c_t i2c_dev;                      /**< I2C device      */
+    uint8_t i2c_addr;                   /**< I2C address     */
+    at24mac_type_t type;                /**< Device type     */
+} at24mac_params_t;
+
+/**
+ * @brief   Get the unique EUI48 address from a AT24MAC4xx chip
+ *
+ * @param[in] dev       Index of the AT24Mac chip in the at24mac_params
+ *                      array.
+ * @param[out] addr     memory location to copy the address into.
+ *
+ * @return              0 on success, error otherwise.
+ */
+int at24mac_get_eui48(at24mac_t dev, eui48_t *addr);
+
+/**
+ * @brief   Get the unique EUI64 address from a AT24MAC6xx chip
+ *
+ * @param[in] dev       Index of the AT24Mac chip in the at24mac_params
+ *                      array.
+ * @param[out] addr     memory location to copy the address into.
+ *
+ * @return              0 on success, error otherwise.
+ */
+int at24mac_get_eui64(at24mac_t dev, eui64_t *addr);
+
+/**
+ * @brief   Get the unique ID from a AT24MACxxx chip
+ *
+ * @param[in] dev       Index of the AT24MAC chip in the at24mac_params
+ *                      array.
+ * @param[out] dst      memory location to copy the ID into.
+ *                      Must be able to hold at least @ref AT24MAC_ID_LEN bytes.
+ *
+ * @return              0 on success, error otherwise.
+ */
+int at24mac_get_id128(at24mac_t dev, void *dst);
+
+/**
+ * @brief   Get the type of a AT24MACxxx chip
+ *
+ * @param[in] dev       Index of the AT24MAC chip in the at24mac_params
+ *                      array.
+ *
+ * @return              The type of the device (AT24MAC4XX or AT24MAC6XX)
+ */
+at24mac_type_t at24mac_get_type(at24mac_t dev);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AT24MAC_H */
+/** @} */