1 files changed, 100 insertions, 0 deletions
diff --git a/nuttx/arch/arm/src/stm32/stm32_lsi.c b/nuttx/arch/arm/src/stm32/stm32_lsi.c
new file mode 100644
index 000000000..e365fbf06
--- /dev/null
+++ b/nuttx/arch/arm/src/stm32/stm32_lsi.c
@@ -0,0 +1,100 @@
+/****************************************************************************
+ * arch/arm/src/stm32/stm32_lsi.c
+ *
+ *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.orgr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include "up_arch.h"
+
+#include "stm32_rcc.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: stm32_rcc_enablelsi
+ *
+ * Description:
+ *   Enable the Internal Low-Speed (LSI) RC Oscillator.
+ *
+ ****************************************************************************/
+
+void stm32_rcc_enablelsi(void)
+{
+  /* Enable the Internal Low-Speed (LSI) RC Oscillator by setting the LSION bit
+   * the RCC CSR register.
+   */
+
+  modifyreg32(STM32_RCC_CSR, 0, RCC_CSR_LSION);
+
+  /* Wait for the internal RC 40 kHz oscillator to be stable. */
+
+  while ((getreg32(STM32_RCC_CSR) & RCC_CSR_LSIRDY) == 0);
+}
+
+/****************************************************************************
+ * Name: stm32_rcc_disablelsi
+ *
+ * Description:
+ *   Disable the Internal Low-Speed (LSI) RC Oscillator.
+ *
+ ****************************************************************************/
+
+void stm32_rcc_disablelsi(void)
+{
+  /* Enable the Internal Low-Speed (LSI) RC Oscillator by setting the LSION bit
+   * the RCC CSR register.
+   */
+
+  modifyreg32(STM32_RCC_CSR, RCC_CSR_LSION, 0);
+
+  /* LSIRDY should go low after 3 LSI clock cycles */
+}