SAMA5: Enable the 32.768 crystal if SCHED_TICKLESS is selected

configs/sama5d3-xplained/Kconfig

@@ -20,6 +20,11 @@ config SAMA5D3XPLAINED_528MHZ
 
 endchoice # CPU Frequency
 
+config SAMA5D3XPLAINED_SLOWCLOCK
+	bool
+	default y if SCHED_TICKLESS
+	default n if !SCHED_TICKLESS
+
 choice
 	prompt "SAMA5D3-Xplained DRAM Type"
 	default SAMA5D3XPLAINED_MT47H128M16RT

configs/sama5d3-xplained/README.txt

@@ -2392,7 +2392,8 @@ Tickless OS
   NOTE: In most cases, the slow clock will be used as the timer/counter
   input.  You should enable the 32.768KHz crystal for the slow clock by
   calling sam_sckc_enable().  Otherwise, you will be doing all system
-  timing using the RC clock!
+  timing using the RC clock!  UPDATE: This will now be selected by default
+  when you configure for TICKLESS support.
 
   SAMA5 Timer Usage
   -----------------

configs/sama5d3-xplained/src/sam_boot.c

@@ -41,6 +41,7 @@
 
 #include <debug.h>
 
+#include "sam_sckc.h"
 #include "sama5d3-xplained.h"
 
 /************************************************************************************
@@ -67,6 +68,12 @@
 
 void sam_boardinitialize(void)
 {
+#ifdef CONFIG_SAMA5D3XPLAINED_SLOWCLOCK
+  /* Enable the external slow clock */
+
+  sam_sckc_enable(true);
+#endif
+
   /* Configure SPI chip selects if 1) SPI is enable, and 2) the weak function
    * sam_spiinitialize() has been brought into the link.
    */

configs/sama5d3x-ek/Kconfig

@@ -248,6 +248,11 @@ config SAMA5D3xEK_OV2640_DEMO
 
 endif # VIDEO_OV2640
 
+config SAMA5D3xEK_SLOWCLOCK
+	bool
+	default y if SCHED_TICKLESS
+	default n if !SCHED_TICKLESS
+
 if AUDIO_WM8904
 
 config SAMA5D3xEK_WM8904_I2CFREQUENCY
@@ -266,6 +271,7 @@ choice
 
 config SAMA5D3xEK_WM8904_SRCMAIN
 	bool "Main Clock (12MHz)"
+	select SAMA5D3xEK_SLOWCLOCK
 
 config SAMA5D3xEK_WM8904_SRCSCK
 	bool "Slow XTAL (32.768KHz)"

configs/sama5d3x-ek/README.txt

@@ -2708,7 +2708,8 @@ Tickless OS
   NOTE: In most cases, the slow clock will be used as the timer/counter
   input.  You should enable the 32.768KHz crystal for the slow clock by
   calling sam_sckc_enable().  Otherwise, you will be doing all system
-  timing using the RC clock!
+  timing using the RC clock!  UPDATE: This will now be selected by default
+  when you configure for TICKLESS support.
 
   SAMA5 Timer Usage
   -----------------

configs/sama5d3x-ek/src/sam_boot.c

@@ -41,6 +41,7 @@
 
 #include <debug.h>
 
+#include "sam_sckc.h"
 #include "sama5d3x-ek.h"
 
 /************************************************************************************
@@ -60,13 +61,19 @@
  *
  * Description:
  *   All SAMA5 architectures must provide the following entry point.  This entry
- *   point is called early in the intitialization -- after all memory has been
+ *   point is called early in the initialization -- after all memory has been
  *   configured and mapped but before any devices have been initialized.
  *
  ************************************************************************************/
 
 void sam_boardinitialize(void)
 {
+#ifdef CONFIG_SAMA5D3xEK_SLOWCLOCK
+  /* Enable the external slow clock */
+
+  sam_sckc_enable(true);
+#endif
+
   /* Configure SPI chip selects if 1) SPI is enable, and 2) the weak function
    * sam_spiinitialize() has been brought into the link.
    */

configs/sama5d3x-ek/src/sam_wm8904.c

@@ -56,7 +56,6 @@
 #include "sam_pio.h"
 #include "sam_twi.h"
 #include "sam_ssc.h"
-#include "sam_sckc.h"
 #include "sam_pck.h"
 
 #include "sama5d3x-ek.h"
@@ -293,9 +292,10 @@ int sam_wm8904_initialize(int minor)
        */
 
 #ifdef CONFIG_SAMA5D3xEK_WM8904_SRCSCK
-      /* Drive the DAC with the slow clock (32.768 KHz) */
+      /* Drive the DAC with the slow clock (32.768 KHz).  The slow clock was
+       * enabled in sam_boot.c if needed.
+       */
 
-      sam_sckc_enable(true);
       (void)sam_pck_configure(PCK0, PCKSRC_SCK, BOARD_SLOWCLK_FREQUENCY);
 #else
       /* Drive the DAC with the main clock (12 MHz) */

configs/sama5d4-ek/Kconfig

@@ -268,6 +268,11 @@ config SAMA5D4EK_CHANNEL
 		Selects the PWM channel number that will be used to perform the PWM
 		test.  See apps/examples/pwm.
 
+config SAMA5D4EK_SLOWCLOCK
+	bool
+	default y if SCHED_TICKLESS
+	default n if !SCHED_TICKLESS
+
 if AUDIO_WM8904
 
 config SAMA5D4EK_WM8904_I2CFREQUENCY
@@ -289,6 +294,7 @@ config SAMA5D4EK_WM8904_SRCMAIN
 
 config SAMA5D4EK_WM8904_SRCSCK
 	bool "Slow XTAL (32.768KHz)"
+	select SAMA5D4EK_SLOWCLOCK
 
 endchoice # WM8904 MCLK source
 endif # AUDIO_WM8904

configs/sama5d4-ek/README.txt

@@ -3172,7 +3172,14 @@ Tickless OS
   NOTE: In most cases, the slow clock will be used as the timer/counter
   input.  You should enable the 32.768KHz crystal for the slow clock by
   calling sam_sckc_enable().  Otherwise, you will be doing all system
-  timing using the RC clock!
+  timing using the RC clock!  UPDATE: This will now be selected by default
+  when you configure for TICKLESS support.
+
+  UPDATE: As of this writing (2014-8-11), the Tickless support is
+  functional.  However, the timing for all delays appears to be half the
+  duration that it should be.  I don't see anything wrong with the setup
+  and I am suspecting that there may be something I don't understand about
+  the counting frequency.
 
   SAMA5 Timer Usage
   -----------------

configs/sama5d4-ek/src/sam_boot.c

@@ -41,6 +41,7 @@
 
 #include <debug.h>
 
+#include "sam_sckc.h"
 #include "sama5d4-ek.h"
 
 /************************************************************************************
@@ -60,13 +61,19 @@
  *
  * Description:
  *   All SAMA5 architectures must provide the following entry point.  This entry
- *   point is called early in the intitialization -- after all memory has been
+ *   point is called early in the initialization -- after all memory has been
  *   configured and mapped but before any devices have been initialized.
  *
  ************************************************************************************/
 
 void sam_boardinitialize(void)
 {
+#ifdef CONFIG_SAMA5D4EK_SLOWCLOCK
+  /* Enable the external slow clock */
+
+  sam_sckc_enable(true);
+#endif
+
   /* Configure SPI chip selects if 1) SPI is enable, and 2) the weak function
    * sam_spiinitialize() has been brought into the link.
    */

configs/sama5d4-ek/src/sam_wm8904.c

@@ -56,7 +56,6 @@
 #include "sam_pio.h"
 #include "sam_twi.h"
 #include "sam_ssc.h"
-#include "sam_sckc.h"
 #include "sam_pck.h"
 
 #include "sama5d4-ek.h"
@@ -293,9 +292,10 @@ int sam_wm8904_initialize(int minor)
        */
 
 #ifdef CONFIG_SAMA5D4EK_WM8904_SRCSCK
-      /* Drive the DAC with the slow clock (32.768 KHz) */
+      /* Drive the DAC with the slow clock (32.768 KHz).  The slow clock was
+       * enabled in sam_boot.c if needed.
+       */
 
-      sam_sckc_enable(true);
       (void)sam_pck_configure(PCK2, PCKSRC_SCK, BOARD_SLOWCLK_FREQUENCY);
 #else
       /* Drive the DAC with the main clock (12 MHz) */