Add SAM3/4 RTT driver. From Bob Doiron

1 files changed, 23 insertions, 24 deletions

diff --git a/nuttx/arch/arm/src/sam34/sam_tc.c b/nuttx/arch/arm/src/sam34/sam_tc.c
index 27dbd1642..b955d6bb0 100644
--- a/nuttx/arch/arm/src/sam34/sam_tc.c
+++ b/nuttx/arch/arm/src/sam34/sam_tc.c
@@ -106,7 +106,6 @@ struct sam34_lowerhalf_s
   uint32_t clkticks;        /* actual clock ticks for current interval */
   bool     started;         /* The timer has been started */
   uint16_t periphid;        /* peripheral id */
-  uint16_t debug;
 };
 
 /****************************************************************************
@@ -134,7 +133,7 @@ static int      sam34_getstatus(FAR struct timer_lowerhalf_s *lower,
                   FAR struct timer_status_s *status);
 static int      sam34_settimeout(FAR struct timer_lowerhalf_s *lower,
                   uint32_t timeout);
-static tccb_t   sam34_capture(FAR struct timer_lowerhalf_s *lower,
+static tccb_t   sam34_sethandler(FAR struct timer_lowerhalf_s *lower,
                   tccb_t handler);
 static int      sam34_ioctl(FAR struct timer_lowerhalf_s *lower, int cmd,
                   unsigned long arg);
@@ -150,7 +149,7 @@ static const struct timer_ops_s g_tcops =
   .stop       = sam34_stop,
   .getstatus  = sam34_getstatus,
   .settimeout = sam34_settimeout,
-  .capture    = sam34_capture,
+  .sethandler = sam34_sethandler,
   .ioctl      = sam34_ioctl,
 };
 
@@ -267,15 +266,13 @@ static void sam34_putreg(uint32_t val, uint32_t addr)
 static int sam34_interrupt(int irq, FAR void *context)
 {
   FAR struct sam34_lowerhalf_s *priv = &g_tcdevs[irq-SAM_IRQ_TC0];
-  uint16_t regval;
 
   tcvdbg("Entry\n");
   DEBUGASSERT((irq >= SAM_IRQ_TC0) && (irq <= SAM_IRQ_TC5));
 
   /* Check if the interrupt is really pending */
 
-  regval = sam34_getreg(priv->base + SAM_TC_SR_OFFSET);
-  if ((regval & TC_INT_CPCS) != 0)
+  if ((sam34_getreg(priv->base + SAM_TC_SR_OFFSET) & TC_INT_CPCS) != 0)
     {
       uint32_t timeout;
 
@@ -283,7 +280,7 @@ static int sam34_interrupt(int irq, FAR void *context)
 
       if (priv->handler && priv->handler(&priv->timeout))
         {
-          /* Calculate new ticks */
+          /* Calculate new ticks / dither adjustment */
 
           priv->clkticks = ((uint64_t)(priv->adjustment + priv->timeout))*TC_FCLK / 1000000;
 
@@ -323,7 +320,7 @@ static int sam34_interrupt(int irq, FAR void *context)
 static int sam34_start(FAR struct timer_lowerhalf_s *lower)
 {
   FAR struct sam34_lowerhalf_s *priv = (FAR struct sam34_lowerhalf_s *)lower;
-  uint32_t mr_val = 0;
+  uint32_t mr_val;
 
   tcvdbg("Entry\n");
   DEBUGASSERT(priv);
@@ -335,13 +332,14 @@ static int sam34_start(FAR struct timer_lowerhalf_s *lower)
 
   sam_enableperiph0(priv->periphid);                            /* Enable peripheral clock */
   sam34_putreg(TC_CCR_CLKDIS, priv->base + SAM_TC_CCR_OFFSET);  /* Disable counter */
+  sam34_putreg(0, priv->base + SAM_TC_CV_OFFSET);               /* clear counter */
 
   /* TC_CMR_WAVE - waveform mode
    * TC_CMR_WAVSEL_UPAUTO - reset on RC compare (interval timer)
    * TC_CMR_TCCLKS_TIMERCLOCK5 = SCLK
    */
 
-  mr_val |= (TC_CMR_WAVE + TC_CMR_WAVSEL_UPAUTO + TC_CMR_TCCLKS_TIMERCLOCK5);
+  mr_val = (TC_CMR_WAVE + TC_CMR_WAVSEL_UPAUTO + TC_CMR_TCCLKS_TIMERCLOCK5);
   sam34_putreg(mr_val, priv->base + SAM_TC_CMR_OFFSET);
 
   sam34_putreg(priv->clkticks, priv->base + SAM_TC_RC_OFFSET);   /* Set interval */
@@ -381,7 +379,7 @@ static int sam34_stop(FAR struct timer_lowerhalf_s *lower)
   tcvdbg("Entry\n");
   DEBUGASSERT(priv);
 
-  if(!priv->started)
+  if (!priv->started)
     {
       return -EINVAL;
     }
@@ -430,7 +428,7 @@ static int sam34_getstatus(FAR struct timer_lowerhalf_s *lower,
 
   if (priv->handler)
     {
-      status->flags |= TCFLAGS_CAPTURE;
+      status->flags |= TCFLAGS_HANDLER;
     }
 
   /* Return the actual timeout is milliseconds */
@@ -440,7 +438,7 @@ static int sam34_getstatus(FAR struct timer_lowerhalf_s *lower,
   /* Get the time remaining until the timer expires (in microseconds) */
 
   elapsed = sam34_getreg(priv->base + SAM_TC_CV_OFFSET);
-  status->timeleft = (priv->timeout * elapsed) / (priv->clkticks + 1); /* TODO - check on this +1 */
+  status->timeleft = ((uint64_t)priv->timeout * elapsed) / (priv->clkticks + 1); /* TODO - check on this +1 */
 
   tcvdbg("  flags    : %08x\n", status->flags);
   tcvdbg("  timeout  : %d\n", status->timeout);
@@ -470,6 +468,12 @@ static int sam34_settimeout(FAR struct timer_lowerhalf_s *lower,
   FAR struct sam34_lowerhalf_s *priv = (FAR struct sam34_lowerhalf_s *)lower;
 
   DEBUGASSERT(priv);
+
+  if (priv->started)
+    {
+      return -EPERM;
+    }
+
   tcvdbg("Entry: timeout=%d\n", timeout);
 
   /* Can this timeout be represented? */
@@ -486,21 +490,17 @@ static int sam34_settimeout(FAR struct timer_lowerhalf_s *lower,
   timeout = (1000000ULL * priv->clkticks) / TC_FCLK;          /* Truncated timeout */
   priv->adjustment = priv->timeout - timeout;                 /* Truncated time to be added to next interval (dither) */
 
-  tcvdbg("fwdt=%d reload=%d timout=%d, adjustment=%d\n",
-         TC_FCLK, reload, priv->timeout, priv->adjustment);
-
-  /* Don't commit to MR register until started! */
+  tcvdbg("fclk=%d clkticks=%d timout=%d, adjustment=%d\n",
+         TC_FCLK, priv->clkticks, priv->timeout, priv->adjustment);
 
   return OK;
 }
 
 /****************************************************************************
- * Name: sam34_capture
+ * Name: sam34_sethandler
  *
  * Description:
- *   Don't reset on timer timeout; instead, call this user provider
- *   timeout handler.  NOTE:  Providing handler==NULL will restore the reset
- *   behavior.
+ *   Call this user provided timeout handler.
  *
  * Input Parameters:
  *   lower      - A pointer the publicly visible representation of the "lower-half"
@@ -511,13 +511,12 @@ static int sam34_settimeout(FAR struct timer_lowerhalf_s *lower,
  *
  * Returned Values:
  *   The previous timer expiration function pointer or NULL is there was
- *   no previous function pointer, i.e., if the previous behavior was
- *   reset-on-expiration (NULL is also returned if an error occurs).
+ *   no previous function pointer.
  *
  ****************************************************************************/
 
-static tccb_t sam34_capture(FAR struct timer_lowerhalf_s *lower,
-                            tccb_t handler)
+static tccb_t sam34_sethandler(FAR struct timer_lowerhalf_s *lower,
+                               tccb_t handler)
 {
   FAR struct sam34_lowerhalf_s *priv = (FAR struct sam34_lowerhalf_s *)lower;
   irqstate_t flags;