Add function to change fract dividers

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2466 42af7a65-404d-4744-a932-0658087f49c3

arch/arm/src/lpc313x/Make.defs

@@ -50,7 +50,7 @@ CGU_CSRCS	= lpc313x_bcrndx.c lpc313x_clkdomain.c lpc313x_clkexten.c \
 		  lpc313x_clkfreq.c lpc313x_clkinit.c lpc313x_defclk.c \
 		  lpc313x_esrndx.c lpc313x_fdcndx.c lpc313x_fdivinit.c \
 		  lpc313x_freqin.c lpc313x_pllconfig.c lpc313x_resetclks.c \
-		  lpc313x_setfreqin.c lpc313x_softreset.c
+		  lpc313x_setfreqin.c lpc313x_setfdiv.c lpc313x_softreset.c
 
 CHIP_ASRCS	= $(CGU_ASRCS)
 CHIP_CSRCS	= lpc313x_allocateheap.c lpc313x_boot.c lpc313x_irq.c \

arch/arm/src/lpc313x/lpc313x_cgudrvr.h

@@ -646,7 +646,9 @@ EXTERN void lpc313x_clkinit(const struct lpc313x_clkinit_s* cfg);
  * Name: lpc313x_fdivinit
  *
  * Description:
- *   Enable and configure (or disable) a fractional divider.
+ *   Enable and configure (or disable) a fractional divider.  For
+ *   internal us only... see lpc313x_setfdiv() the externally usable
+ *   function.
  *
  ************************************************************************/
 
@@ -654,6 +656,19 @@ EXTERN uint32_t lpc313x_fdivinit(int fdcndx,
                                  const struct lpc313x_fdivconfig_s *fdiv,
                                  bool enable);
 
+/************************************************************************
+ * Name: lpc313x_setfdiv
+ *
+ * Description:
+ *   Set/reset subdomain frequency containing the specified clock using
+ *   the provided divider settings
+ *
+ ************************************************************************/
+
+EXTERN void lpc313x_setfdiv(enum lpc313x_domainid_e dmnid,
+                            enum lpc313x_clockid_e clkid,
+                            const struct lpc313x_subdomainconfig_s *fdiv);
+
 /****************************************************************************
  * Name: lpc313x_pllconfig
  *

arch/arm/src/lpc313x/lpc313x_setfdiv.c

+/****************************************************************************
+ * arch/arm/src/lpc313x/lpc313x_setfdiv.c
+ *
+ *   Copyright (C) 2009 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 <stdint.h>
+#include <stdbool.h>
+
+#include <arch/board/board.h>
+
+#include "lpc313x_cgu.h"
+#include "lpc313x_cgudrvr.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lpc313x_setfdiv
+ *
+ * Description:
+ *   Set/reset subdomain frequency containing the specified clock using the
+ *   provided divider settings
+ *
+ ****************************************************************************/
+
+void lpc313x_setfdiv(enum lpc313x_domainid_e dmnid,
+                     enum lpc313x_clockid_e clkid,
+                     const struct lpc313x_subdomainconfig_s *fdiv)
+{
+  uint32_t regaddr;
+  unsigned int basefreq;
+  int fdcndx;
+  int bcrndx;
+  
+  /* Get the frequency divider associated with this clock */
+
+  fdcndx = lpc313x_fdcndx(clkid, dmnid);
+
+  /* Does this clock have a frequency divicer? */
+
+  if (fdcndx != FDCNDX_INVALID)
+    {
+      /* Yes.. Save the current reference frequency selection */
+
+      regaddr  = LPC313X_CGU_SSR_OFFSET((int)dmnid);
+      basefreq = (getreg32(regaddr) & CGU_SSR_FS_MASK) >> CGU_SSR_FS_SHIFT;
+      
+      /* Switch domain to FFAST input */
+
+      lpc313x_selectfreqin(dmnid, CGU_FS_FFAST);
+
+      /* Get the index of the associated BCR register.  Does this domain
+       * have a BCR?
+       */
+
+      bcrndx = lp313x_bcrndx(dmnid);
+      if (bcrndx != BCRNDX_INVALID)
+        {
+
+          /* Yes... Disable the BCR */
+
+          regaddr = LPC313X_CGU_BCR(bcrndx);
+          putreg32(0, regaddr);
+        }
+
+      /* Change fractional divider to the provided settings */
+
+      lpc313x_fdivinit(fdcndx, fdiv, true);
+
+      /* Re-enable the BCR (if one is associated with this domain) */
+
+      if (bcrndx != BCRNDX_INVALID)
+        {
+          regaddr = LPC313X_CGU_BCR(bcrndx);
+          putreg32(CGU_BCR_FDRUN, regaddr);
+        }
+
+      /* Switch the domain back to its original base frequency */
+
+      lpc313x_selectfreqin(dmnid, basefreq);
+    }
+}