From f571b507132cc77e401dee68535c2b9f3370c60c Mon Sep 17 00:00:00 2001
From: barthess <barthess@35acf78f-673a-0410-8e92-d51de3d6d3f4>
Date: Wed, 27 Mar 2013 20:03:40 +0000
Subject: STM32. GPT. Added abillity to change interval of running GPT unit on
 the fly.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@5510 35acf78f-673a-0410-8e92-d51de3d6d3f4
---
 os/hal/include/gpt.h             | 18 ++++++++++++++++++
 os/hal/platforms/STM32/gpt_lld.h | 16 ++++++++++++++++
 os/hal/src/gpt.c                 | 24 ++++++++++++++++++++++++
 3 files changed, 58 insertions(+)

diff --git a/os/hal/include/gpt.h b/os/hal/include/gpt.h
index 4a8245df5..379b90be9 100644
--- a/os/hal/include/gpt.h
+++ b/os/hal/include/gpt.h
@@ -76,6 +76,23 @@ typedef void (*gptcallback_t)(GPTDriver *gptp);
 /* Driver macros.                                                            */
 /*===========================================================================*/
 
+/**
+ * @brief   Changes the interval of GPT peripheral.
+ * @details This function changes the interval of a running GPT unit.
+ * @pre     The GPT unit must have been activated using @p gptStart().
+ * @pre     The GPT unit must have been running in continuous mode using
+ *          @p gptStartContinuous().
+ * @post    The GPT unit interval is changed to the new value.
+ *
+ * @param[in] gptp      pointer to a @p GPTDriver object
+ * @param[in] interval  new cycle time in timer ticks
+ *
+ * @iclass
+ */
+#define stm32_gptChangeIntervalI(gptp, interval) {                            \
+  gpt_lld_change_interval(gptp, interval);                                    \
+}
+
 /*===========================================================================*/
 /* External declarations.                                                    */
 /*===========================================================================*/
@@ -89,6 +106,7 @@ extern "C" {
   void gptStop(GPTDriver *gptp);
   void gptStartContinuous(GPTDriver *gptp, gptcnt_t interval);
   void gptStartContinuousI(GPTDriver *gptp, gptcnt_t interval);
+  void stm32_gptChangeInterval(GPTDriver *gptp, gptcnt_t interval);
   void gptStartOneShot(GPTDriver *gptp, gptcnt_t interval);
   void gptStartOneShotI(GPTDriver *gptp, gptcnt_t interval);
   void gptStopTimer(GPTDriver *gptp);
diff --git a/os/hal/platforms/STM32/gpt_lld.h b/os/hal/platforms/STM32/gpt_lld.h
index 8a8ec4059..3421edbdd 100644
--- a/os/hal/platforms/STM32/gpt_lld.h
+++ b/os/hal/platforms/STM32/gpt_lld.h
@@ -267,6 +267,22 @@ struct GPTDriver {
 /* Driver macros.                                                            */
 /*===========================================================================*/
 
+/**
+ * @brief   Changes the interval of GPT peripheral.
+ * @details This function changes the interval of a running GPT unit.
+ * @pre     The GPT unit must have been activated using @p gptStart().
+ * @pre     The GPT unit must have been running in continuous mode using
+ *          @p gptStartContinuous().
+ * @post    The GPT unit interval is changed to the new value.
+ * @note    The function has effect at the next cycle start.
+ *
+ * @param[in] gptp      pointer to a @p GPTDriver object
+ * @param[in] interval  new cycle time in timer ticks
+ * @notapi
+ */
+#define gpt_lld_change_interval(gptp, interval)                               \
+  ((gptp)->tim->ARR = (uint16_t)((interval) - 1))
+
 /*===========================================================================*/
 /* External declarations.                                                    */
 /*===========================================================================*/
diff --git a/os/hal/src/gpt.c b/os/hal/src/gpt.c
index 48db68174..9b7c0d9a6 100644
--- a/os/hal/src/gpt.c
+++ b/os/hal/src/gpt.c
@@ -116,6 +116,30 @@ void gptStop(GPTDriver *gptp) {
   chSysUnlock();
 }
 
+/**
+ * @brief   Changes the interval of GPT peripheral.
+ * @details This function changes the interval of a running GPT unit.
+ * @pre     The GPT unit must have been activated using @p gptStart().
+ * @pre     The GPT unit must have been running in continuous mode using
+ *          @p gptStartContinuous().
+ * @post    The GPT unit interval is changed to the new value.
+ *
+ * @param[in] gptp      pointer to a @p GPTDriver object
+ * @param[in] interval  new cycle time in timer ticks
+ *
+ * @api
+ */
+void stm32_gptChangeInterval(GPTDriver *gptp, gptcnt_t interval) {
+
+  chDbgCheck(gptp != NULL, "gptChangeInterval");
+
+  chSysLock();
+  chDbgAssert(gptp->state == GPT_CONTINUOUS,
+              "gptChangeInterval(), #1", "invalid state");
+  stm32_gptChangeIntervalI(gptp, interval);
+  chSysUnlock();
+}
+
 /**
  * @brief   Starts the timer in continuous mode.
  *
-- 
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