STM32 PVD: Adds support for STM32's Programmable Voltage Detector feature. I put register access behind CONFIG_STM32_ENERGYLITE as have not checked F1/F2/F4 etc. manuals. Tested on STM32L1. PVD interrupt looks generic, at least #defines it needs are in headers for every chip variant. By Dmitry Nikolaev, submitted by Juha Niskanen.

arch/arm/src/stm32/Make.defs

@@ -177,7 +177,7 @@ CHIP_CSRCS += stm32_eth.c
 endif
 
 ifeq ($(CONFIG_STM32_PWR),y)
-CHIP_CSRCS += stm32_pwr.c
+CHIP_CSRCS += stm32_pwr.c stm32_exti_pwr.c
 endif
 
 ifeq ($(CONFIG_RTC),y)

arch/arm/src/stm32/chip/stm32_pwr.h

@@ -73,7 +73,7 @@
 #    define PWR_CR_1p9V        (0 << PWR_CR_PLS_SHIFT) /* 000: 1.9 V */
 #    define PWR_CR_2p1V        (1 << PWR_CR_PLS_SHIFT) /* 001: 2.1 V */
 #    define PWR_CR_2p3V        (2 << PWR_CR_PLS_SHIFT) /* 010: 2.3 V */
-#    define PWR_CR_2pvV        (3 << PWR_CR_PLS_SHIFT) /* 011: 2.5 V */
+#    define PWR_CR_2p5V        (3 << PWR_CR_PLS_SHIFT) /* 011: 2.5 V */
 #    define PWR_CR_2p7V        (4 << PWR_CR_PLS_SHIFT) /* 100: 2.7 V */
 #    define PWR_CR_2p9V        (5 << PWR_CR_PLS_SHIFT) /* 101: 2.9 V */
 #    define PWR_CR_3p1V        (6 << PWR_CR_PLS_SHIFT) /* 110: 3.1 V */

arch/arm/src/stm32/stm32_exti_pwr.c

@@ -0,0 +1,169 @@
+/****************************************************************************
+ * arch/arm/src/stm32/stm32_exti_pwr.c
+ *
+ *   Copyright (C) 2009, 2011-2012, 2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2015 Haltian Ltd. All rights reserved.
+ *   Authors: Gregory Nutt <gnutt@nuttx.org>
+ *            Dmitry Nikolaev <dmitry.nikolaev@haltian.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/irq.h>
+#include <nuttx/arch.h>
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <errno.h>
+
+#include <arch/irq.h>
+
+#include "up_arch.h"
+#include "chip.h"
+#include "stm32_gpio.h"
+#include "stm32_exti.h"
+#include "stm32_exti_pwr.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/* Interrupt handlers attached to the PVD EXTI */
+
+static xcpt_t stm32_exti_pvd_callback;
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+ /****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: stm32_exti_pvd_isr
+ *
+ * Description:
+ *   EXTI PVD interrupt service routine/dispatcher
+ *
+ ****************************************************************************/
+
+static int stm32_exti_pvd_isr(int irq, void *context)
+{
+  int ret = OK;
+
+  /* Clear the pending EXTI interrupt */
+
+  putreg32(EXTI_PVD_LINE, STM32_EXTI_PR);
+
+  /* And dispatch the interrupt to the handler */
+
+  if (stm32_exti_pvd_callback)
+    {
+      ret = stm32_exti_pvd_callback(irq, context);
+    }
+
+  return ret;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: stm32_exti_pvd
+ *
+ * Description:
+ *   Sets/clears EXTI PVD interrupt.
+ *
+ * Parameters:
+ *  - rising/falling edge: enables interrupt on rising/falling edge
+ *  - event:  generate event when set
+ *  - func:   when non-NULL, generate interrupt
+ *
+ * Returns:
+ *   The previous value of the interrupt handler function pointer.  This
+ *   value may, for example, be used to restore the previous handler when
+ *   multiple handlers are used.
+ *
+ ****************************************************************************/
+
+xcpt_t stm32_exti_pvd(bool risingedge, bool fallingedge, bool event,
+                      xcpt_t func)
+{
+  xcpt_t oldhandler;
+
+  /* Get the previous GPIO IRQ handler; Save the new IRQ handler. */
+
+  oldhandler = stm32_exti_pvd_callback;
+  stm32_exti_pvd_callback = func;
+
+  /* Install external interrupt handlers (if not already attached) */
+
+  if (func)
+    {
+      irq_attach(STM32_IRQ_PVD, stm32_exti_pvd_isr);
+      up_enable_irq(STM32_IRQ_PVD);
+    }
+  else
+    {
+      up_disable_irq(STM32_IRQ_PVD);
+    }
+
+  /* Configure rising/falling edges */
+
+  modifyreg32(STM32_EXTI_RTSR,
+              risingedge ? 0 : EXTI_PVD_LINE,
+              risingedge ? EXTI_PVD_LINE : 0);
+  modifyreg32(STM32_EXTI_FTSR,
+              fallingedge ? 0 : EXTI_PVD_LINE,
+              fallingedge ? EXTI_PVD_LINE : 0);
+
+  /* Enable Events and Interrupts */
+
+  modifyreg32(STM32_EXTI_EMR,
+              event ? 0 : EXTI_PVD_LINE,
+              event ? EXTI_PVD_LINE : 0);
+  modifyreg32(STM32_EXTI_IMR,
+              func ? 0 : EXTI_PVD_LINE,
+              func ? EXTI_PVD_LINE : 0);
+
+  /* Return the old IRQ handler */
+
+  return oldhandler;
+}

arch/arm/src/stm32/stm32_exti_pwr.h

@@ -0,0 +1,71 @@
+/****************************************************************************
+ * arch/arm/src/stm32/stm32_exti_pwr.h
+ *
+ *   Copyright (C) 2015 Haltian Ltd. All rights reserved.
+ *   Authors: Dmitry Nikolaev <dmitry.nikolaev@haltian.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#ifndef STM32_EXTI_PWR_H_
+#define STM32_EXTI_PWR_H_
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <stdbool.h>
+#include <nuttx/irq.h>
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: stm32_exti_pvd
+ *
+ * Description:
+ *   Sets/clears EXTI PVD interrupt.
+ *
+ * Parameters:
+ *  - rising/falling edge: enables interrupt on rising/falling edge
+ *  - event:  generate event when set
+ *  - func:   when non-NULL, generate interrupt
+ *
+ * Returns:
+ *   The previous value of the interrupt handler function pointer.  This
+ *   value may, for example, be used to restore the previous handler when
+ *   multiple handlers are used.
+ *
+ ****************************************************************************/
+
+xcpt_t stm32_exti_pvd(bool risingedge, bool fallingedge, bool event,
+                      xcpt_t func);
+
+#endif /* STM32_EXTI_PWR_H_ */

arch/arm/src/stm32/stm32_pwr.c

@@ -167,7 +167,7 @@ void stm32_pwr_enablebreg(bool regon)
  * Name: stm32_pwr_setvos
  *
  * Description:
- *   Set voltage scaling for EneryLite devices.
+ *   Set voltage scaling for EnergyLite devices.
  *
  * Input Parameters:
  *   vos - Properly aligned voltage scaling select bits for the PWR_CR register.
@@ -204,6 +204,71 @@ void stm32_pwr_setvos(uint16_t vos)
 
   while ((stm32_pwr_getreg(STM32_PWR_CSR_OFFSET) & PWR_CSR_VOSF) != 0);
 }
-#endif
+
+/************************************************************************************
+ * Name: stm32_pwr_setpvd
+ *
+ * Description:
+ *   Sets power voltage detector
+ *
+ * Input Parameters:
+ *   pls - PVD level
+ *
+ * Returned Values:
+ *   None
+ *
+ * Assumptions:
+ *   At present, this function is called only from initialization logic.  If used
+ *   for any other purpose that protection to assure that its operation is atomic
+ *   will be required.
+ *
+ ************************************************************************************/
+
+void stm32_pwr_setpvd(uint16_t pls)
+{
+  uint16_t regval;
+
+  /* Set PLS */
+
+  regval = stm32_pwr_getreg(STM32_PWR_CR_OFFSET);
+  regval &= ~PWR_CR_PLS_MASK;
+  regval |= (pls & PWR_CR_PLS_MASK);
+
+  /* Write value to register */
+
+  stm32_pwr_putreg(STM32_PWR_CR_OFFSET, regval);
+}
+
+/************************************************************************************
+ * Name: stm32_pwr_enablepvd
+ *
+ * Description:
+ *   Enable the Programmable Voltage Detector
+ *
+ ************************************************************************************/
+
+void stm32_pwr_enablepvd(void)
+{
+  /* Enable PVD by setting the PVDE bit in PWR_CR register. */
+
+  stm32_pwr_modifyreg(STM32_PWR_CR_OFFSET, 0, PWR_CR_PVDE);
+}
+
+/************************************************************************************
+ * Name: stm32_pwr_disablepvd
+ *
+ * Description:
+ *   Disable the Programmable Voltage Detector
+ *
+ ************************************************************************************/
+
+void stm32_pwr_disablepvd(void)
+{
+  /* Disable PVD by clearing the PVDE bit in PWR_CR register. */
+
+  stm32_pwr_modifyreg(STM32_PWR_CR_OFFSET, PWR_CR_PVDE, 0);
+}
+
+#endif /* CONFIG_STM32_ENERGYLITE */
 
 #endif /* CONFIG_STM32_PWR */

arch/arm/src/stm32/stm32_pwr.h

@@ -112,7 +112,7 @@ void stm32_pwr_enablebreg(bool regon);
  * Name: stm32_pwr_setvos
  *
  * Description:
- *   Set voltage scaling for EneryLite devices.
+ *   Set voltage scaling for EnergyLite devices.
  *
  * Input Parameters:
  *   vos - Properly aligned voltage scaling select bits for the PWR_CR register.
@@ -129,7 +129,47 @@ void stm32_pwr_enablebreg(bool regon);
 
 #ifdef CONFIG_STM32_ENERGYLITE
 void stm32_pwr_setvos(uint16_t vos);
-#endif
+
+/************************************************************************************
+ * Name: stm32_pwr_setpvd
+ *
+ * Description:
+ *   Sets power voltage detector for EnergyLite devices.
+ *
+ * Input Parameters:
+ *   pls - PVD level
+ *
+ * Returned Values:
+ *   None
+ *
+ * Assumptions:
+ *   At present, this function is called only from initialization logic.
+ *
+ ************************************************************************************/
+
+void stm32_pwr_setpvd(uint16_t pls);
+
+/************************************************************************************
+ * Name: stm32_pwr_enablepvd
+ *
+ * Description:
+ *   Enable the Programmable Voltage Detector
+ *
+ ************************************************************************************/
+
+void stm32_pwr_enablepvd(void);
+
+/************************************************************************************
+ * Name: stm32_pwr_disablepvd
+ *
+ * Description:
+ *   Disable the Programmable Voltage Detector
+ *
+ ************************************************************************************/
+
+void stm32_pwr_disablepvd(void);
+
+#endif /* CONFIG_STM32_ENERGYLITE */
 
 #undef EXTERN
 #if defined(__cplusplus)