cpu/kinetis: implement power modes for pm_layered

cpu/kinetis/Makefile.dep

@@ -18,5 +18,6 @@ else ifneq (,$(filter periph_mcg,$(FEATURES_USED)))
 endif
 
 USEMODULE += periph_wdog
+USEMODULE += pm_layered
 
 include $(RIOTCPU)/cortexm_common/Makefile.dep

cpu/kinetis/Makefile.features

@@ -1,4 +1,5 @@
 FEATURES_PROVIDED += periph_cpuid
+FEATURES_PROVIDED += periph_pm
 
 # TRNG driver is not implemented for mkw41z models
 _KINETIS_CPU_MODELS_WITHOUT_HWRNG += mkw41z256vht4 mkw41z512vht4

cpu/kinetis/include/periph_cpu.h

@@ -130,9 +130,32 @@ typedef uint16_t gpio_t;
 #define PERIPH_TIMER_PROVIDES_SET
 
 /**
- * @brief   number of usable power modes
+ * @name    Kinetis power mode configuration
+ * @{
  */
-#define PM_NUM_MODES    (1U)
+#define PM_NUM_MODES    (3U)
+enum {
+    KINETIS_PM_LLS  = 0,
+    KINETIS_PM_VLPS = 1,
+    KINETIS_PM_STOP = 2,
+    KINETIS_PM_WAIT = 3,
+};
+#if MODULE_PM_LAYERED
+#include "pm_layered.h"
+/**
+ * @brief   pm_block iff pm_layered is used
+ */
+#define PM_BLOCK(x) pm_block(x)
+/**
+ * @brief   pm_unblock iff pm_layered is used
+ */
+#define PM_UNBLOCK(x) pm_unblock(x)
+#else
+/* ignore these calls when not using pm_layered */
+#define PM_BLOCK(x)
+#define PM_UNBLOCK(x)
+#endif
+/** @} */
 
 #ifdef RTC
 /* All Kinetis CPUs have exactly one RTC hardware module, except for the KL02

cpu/kinetis/periph/pm.c

@@ -26,17 +26,92 @@
 #define ENABLE_DEBUG (0)
 #include "debug.h"
 
-/**
+/* Set to 1 to use the LEDx macros to show which sleep mode is entered */
- * @note    The current PM implementation is very much simplified down to only
+#define ENABLE_LEDS (0)
- *          using the 'WAIT' mode. This implementation must be further expanded
+
- *          to make use of the available and more efficient (deep) sleep modes
+#if ENABLE_LEDS
- *          of the Kinetis CPUs.
+#include "board.h"
- */
+#define PM_LED(x, state) LED ## x ## _ ## state
+#else
+#define PM_LED(x, state)
+#endif
+
+/* SMC_PMCTRL_STOPM masks */
+enum {
+    SMC_PMCTRL_STOPM_STOP = 0,
+    /* 1 is reserved */
+    SMC_PMCTRL_STOPM_VLPS = 2,
+    SMC_PMCTRL_STOPM_LLS  = 3,
+    /* VLLS is not supported */
+};
+
+/** Configure which stop mode will be entered when cortexm_sleep(1) is called */
+static inline void pm_stopm(uint8_t stopm)
+{
+    SMC->PMCTRL = (SMC->PMCTRL & ~(SMC_PMCTRL_STOPM_MASK)) | SMC_PMCTRL_STOPM(stopm);
+}
+
 void pm_set(unsigned mode)
 {
+    unsigned deep = 1;
     switch (mode) {
-        case 0:
+        /* Only the CPU stops in this mode. No clocks or peripherals are powered
-            cortexm_sleep(0);
+         * off. This state should always be safe to use, as any interrupt will
+         * wake it. Power consumption in this state is reduced by about 50%. */
+        case KINETIS_PM_WAIT: /* 3 - ARM Sleep */
+            /* WAIT */
+            deep = 0;
+            PM_LED(0, ON);
+            break;
+
+        /* Some system clocks are stopped in this mode. Usage, means of waking,
+         * and power consumption depend heavily on board-level clock and
+         * peripheral configuration.*/
+        /* If the debug hardware has been used since the last POR, the debug
+         * hardware as well as the clock needed to support it will stay on in
+         * this mode. Thus, after flashing, issue a POR before testing it. */
+        case KINETIS_PM_STOP: /* 2 - ARM Deep Sleep */
+            /* STOP */
+            pm_stopm(SMC_PMCTRL_STOPM_STOP);
+            PM_LED(1, ON);
+            break;
+
+        /* Some system clocks are stopped in this mode. Usage, means of waking,
+         * and power consumption depend heavily on board-level clock and
+         * peripheral configuration.*/
+        /* If the debug hardware has been used since the last POR, the debug
+         * hardware as well as the clock needed to support it will stay on in
+         * this mode. Thus, after flashing, issue a POR before testing it. */
+        case KINETIS_PM_VLPS: /* 1 - ARM Deep Sleep */
+            /* VLPS */
+            pm_stopm(SMC_PMCTRL_STOPM_VLPS);
+            PM_LED(2, ON);
+            break;
+
+        /* All clocks except 32kHz are stopped. Wakeup can occur from
+         * interrupts, several (LLWU-enabled) GPIOs, RTC, or (if the board
+         * configuration uses the 32kHz clock for xtimer) xtimer. Debug hardware
+         * is powered off. Power consumption in this state should be on the
+         * order of 5 uA for the MCU alone, with most boards having additional
+         * parts that will raise this amount. */
+        case KINETIS_PM_LLS: /* 0 - ARM Deep Sleep */
+            /* LLSx */
+            pm_stopm(SMC_PMCTRL_STOPM_LLS);
+            PM_LED(0, ON);
+            PM_LED(2, ON);
+            /* Enable LLWU interrupt, or else we can never resume from LLS */
+            /* Clear pending flag first, the LLWU has no purpose in RUN mode, so
+             * if the flag is set then it must be a remainder from handling the
+             * previous wakeup. */
+            LLWU->F1 = 0xffu;
+            LLWU->F2 = 0xffu;
+            NVIC_ClearPendingIRQ(LLWU_IRQn);
+            NVIC_EnableIRQ(LLWU_IRQn);
             break;
     }
+    DEBUG("pm_set(%u)\n", mode);
+    cortexm_sleep(deep);
+    PM_LED(0, OFF);
+    PM_LED(1, OFF);
+    PM_LED(2, OFF);
 }