cpu/cc26xx_cc13xx: implement periph_timer_query_freqs

cpu/cc26xx_cc13xx/Kconfig

@@ -8,6 +8,7 @@
 config CPU_COMMON_CC26XX_CC13XX
     bool
     select HAS_PERIPH_CPUID
+    select HAS_PERIPH_TIMER_QUERY_FREQS
     select HAS_PERIPH_UART
     select HAS_PERIPH_UART_MODECFG
 

cpu/cc26xx_cc13xx/Makefile.features

@@ -1,5 +1,6 @@
 FEATURES_PROVIDED += periph_cpuid
 FEATURES_PROVIDED += periph_uart
 FEATURES_PROVIDED += periph_uart_modecfg
+FEATURES_PROVIDED += periph_timer_query_freqs
 
 -include $(RIOTCPU)/cortexm_common/Makefile.features

cpu/cc26xx_cc13xx/include/periph_cpu_common.h

@@ -143,6 +143,18 @@ typedef struct {
     uint8_t     chn;    /**< number of channels [1,2] */
 } timer_conf_t;
 
+/**
+ * @brief   Maximum number of channels
+ *
+ * @note    32 bit timers only support one channel instead of two. But knowing
+ *          the worst case is useful e.g. for static allocation. Users are
+ *          expected to either do proper error handling with `timer_set()` and
+ *          `timer_set_absolute()`, or at least verify with
+ *          @ref timer_query_channel_numof what the actual number of channels
+ *          of a timer is.
+ */
+#define TIMER_CHANNEL_NUMOF 2
+
 #define PERIPH_I2C_NEED_READ_REG
 #define PERIPH_I2C_NEED_READ_REGS
 #define PERIPH_I2C_NEED_WRITE_REG

cpu/cc26xx_cc13xx/periph/timer.c

@@ -20,8 +20,9 @@
  * @}
  */
 
-#include <stdlib.h>
+#include <inttypes.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "assert.h"
 #include "board.h"
@@ -98,9 +99,44 @@ static inline gpt_reg_t *dev(tim_t tim)
     return ((gpt_reg_t *)(GPT0_BASE | (((uint32_t)tim) << 12)));
 }
 
+uword_t timer_query_freqs_numof(tim_t dev)
+{
+    assert(dev < TIMER_NUMOF);
+    /* 32 bit timers only work at CPU clock */
+    if (timer_config[dev].cfg == GPT_CFG_32T) {
+        return 1;
+    }
+
+    return 256;
+}
+
+uword_t timer_query_channel_numof(tim_t dev)
+{
+    assert(dev < TIMER_NUMOF);
+    return timer_config[dev].chn;
+}
+
+uint32_t timer_query_freqs(tim_t dev, uword_t index)
+{
+    assert(dev < TIMER_NUMOF);
+
+    /* 32 bit timers only work at CPU clock */
+    if (timer_config[dev].cfg == GPT_CFG_32T) {
+        if (index) {
+            return 0;
+        }
+        return RCOSC48M_FREQ;
+    }
+
+    if (index > UINT8_MAX) {
+        return 0;
+    }
+    return RCOSC48M_FREQ / (index + 1);
+}
+
 int timer_init(tim_t tim, uint32_t freq, timer_cb_t cb, void *arg)
 {
-    DEBUG("timer_init(%u, %lu)\n", tim, freq);
+    DEBUG("timer_init(%u, %" PRIu32 ")\n", tim, freq);
     /* make sure given timer is valid */
     if (tim >= TIMER_NUMOF) {
         return -1;
@@ -182,6 +218,8 @@ int timer_set_absolute(tim_t tim, int channel, unsigned int value)
         dev(tim)->TBMATCHR = (timer_config[tim].cfg == GPT_CFG_32T) ?
                              value : (LOAD_VALUE - value);
     }
+
+    /* unmask IRQ */
     dev(tim)->IMR |= chn_isr_cfg[channel].flag;
 
     return 0;