nrf52: add SPI PM support (disable/enable SPI peripheral on sleep)

arch/arm/src/nrf52/Make.defs

@@ -159,3 +159,7 @@ endif
 ifeq ($(CONFIG_NRF52_SAADC),y)
 CHIP_CSRCS += nrf52_adc.c
 endif
+
+ifeq ($(CONFIG_PM),y)
+CHIP_CSRCS += nrf52_pminitialize.c
+endif

arch/arm/src/nrf52/nrf52_pminitialize.c

@@ -0,0 +1,55 @@
+/****************************************************************************
+ * arch/arm/src/nrf52/nrf52_pminitialize.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/power/pm.h>
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: arm_pminitialize
+ *
+ * Description:
+ *   This function is called by MCU-specific logic at power-on reset in
+ *   order to provide one-time initialization the power management subsystem.
+ *   This function must be called *very* early in the initialization sequence
+ *   *before* any other device drivers are initialized (since they may
+ *   attempt to register with the power management subsystem).
+ *
+ * Input Parameters:
+ *   None.
+ *
+ * Returned Value:
+ *   None.
+ *
+ ****************************************************************************/
+
+void arm_pminitialize(void)
+{
+  /* Then initialize the NuttX power management subsystem proper */
+
+  pm_initialize();
+}

include/nuttx/power/pm.h

@@ -232,7 +232,7 @@ struct pm_governor_s
    *
    *   NOTE: since this will be called from pm_initialize(), the system
    *   is in very early boot state when this callback is invoked. Thus,
-   *   only ver basic initialization should be performed (e.g. no memory
+   *   only very basic initialization should be performed (e.g. no memory
    *   should be allocated).
    *
    **************************************************************************/