Merge pull request #20144 from maribu/periph_timer_query_freq-kinetis

cpu/kinetis: implement periph_timer_query_freqs

cpu/kinetis/Kconfig

@@ -11,6 +11,7 @@ config CPU_COMMON_KINETIS
     select HAS_PERIPH_GPIO
     select HAS_PERIPH_GPIO_IRQ
     select HAS_PERIPH_PM
+    select HAS_PERIPH_TIMER_QUERY_FREQS
 
     # enable kinetis periph drivers if available
     imply MODULE_PERIPH_ICS

cpu/kinetis/Makefile.features

@@ -1,5 +1,6 @@
 FEATURES_PROVIDED += periph_cpuid
 FEATURES_PROVIDED += periph_pm
+FEATURES_PROVIDED += periph_timer_query_freqs
 
 # TRNG driver is not implemented for mkw41z models
 _KINETIS_CPU_MODELS_WITHOUT_HWRNG += mkw41z256vht4 mkw41z512vht4

cpu/kinetis/include/periph_cpu.h

@@ -144,6 +144,11 @@ typedef uint32_t spi_cs_t;
  */
 #define PERIPH_TIMER_PROVIDES_SET
 
+/**
+ * @brief   Only a single channel supported by the driver/hardware
+ */
+#define TIMER_CHANNEL_NUMOF             1
+
 /**
  * @name    Kinetis power mode configuration
  * @{

cpu/kinetis/periph/timer.c

@@ -26,11 +26,13 @@
 
 #include <stdlib.h>
 
-#include "cpu.h"
 #include "bit.h"
+#include "bitarithm.h"
 #include "board.h"
-#include "periph_conf.h"
+#include "cpu.h"
+#include "macros/utils.h"
 #include "periph/timer.h"
+#include "periph_conf.h"
 
 #ifdef PIT_LTMR64H_LTH_MASK
 /* The KW41Z PIT module provides only one IRQ for all PIT channels combined. */
@@ -611,6 +613,54 @@ static inline void lptmr_irq_handler(tim_t tim)
 #endif
 /* ****** Common timer API functions ****** */
 
+uword_t timer_query_freqs_numof(tim_t dev)
+{
+    assert(dev < TIMER_NUMOF);
+
+    switch (_timer_variant(dev)) {
+    case TIMER_PIT:
+        return UINT32_MAX;
+#ifdef KINETIS_BOARD_HAVE_CONFIGURED_LPTMR
+    case TIMER_LPTMR:
+        /* 16 different pre-scaler values + bypassing the pre-scaler is
+         * supported, resulting in 17 possible frequencies. However, RIOT's
+         * timer API doesn't allow specifying frequencies below 1 Hz, so
+         * we possible have fewer options */
+        {
+            uword_t max_shifts = bitarithm_msb(lptmr_config[_lptmr_index(dev)].base_freq) + 1;
+            return MIN(max_shifts, 17);
+        }
+#endif
+    default:
+        assert(0);
+        return 0;
+    }
+}
+
+uint32_t timer_query_freqs(tim_t dev, uword_t index)
+{
+    assert(dev < TIMER_NUMOF);
+
+    switch (_timer_variant(dev)) {
+    case TIMER_PIT:
+        if (index == UINT32_MAX) {
+            return 0;
+        }
+        return PIT_BASECLOCK / (index + 1);
+#ifdef KINETIS_BOARD_HAVE_CONFIGURED_LPTMR
+    case TIMER_LPTMR:
+        if (index >= 17) {
+            return 0;
+        }
+
+        return lptmr_config[_lptmr_index(dev)].base_freq >> index;
+#endif
+    default:
+        assert(0);
+        return 0;
+    }
+}
+
 int timer_init(tim_t dev, uint32_t freq, timer_cb_t cb, void *arg)
 {
     if ((unsigned int)dev >= TIMER_NUMOF) {