Merge pull request #1419 from bthebaudeau/cc2538-pwm-lpm-register-peripheral

cc2538: pwm: Fix clock and automatically disable PM1+ if running

cpu/cc2538/dev/pwm.c

@@ -46,6 +46,7 @@
 #include "dev/gpio.h"
 #include "dev/sys-ctrl.h"
 #include "dev/pwm.h"
+#include "lpm.h"
 #include <stdio.h>
 #include <stdlib.h>
 /*---------------------------------------------------------------------------*/
@@ -73,6 +74,21 @@ pwm_configured(uint8_t timer, uint8_t ab)
   return 0;
 }
 /*---------------------------------------------------------------------------*/
+static bool
+permit_pm1(void)
+{
+  uint8_t timer, ab;
+
+  for(timer = PWM_TIMER_0; timer <= PWM_TIMER_3; timer++)
+    for(ab = PWM_TIMER_A; ab <= PWM_TIMER_B; ab++)
+      if(pwm_configured(timer, ab) &&
+         REG(PWM_GPTIMER_NUM_TO_BASE(timer) + GPTIMER_CTL) &
+           (ab == PWM_TIMER_A ? GPTIMER_CTL_TAEN : GPTIMER_CTL_TBEN))
+        return false;
+
+  return true;
+}
+/*---------------------------------------------------------------------------*/
 int8_t
 pwm_enable(uint32_t freq, uint8_t duty, uint8_t timer, uint8_t ab)
 {
@@ -95,6 +111,8 @@ pwm_enable(uint32_t freq, uint8_t duty, uint8_t timer, uint8_t ab)
 
   PRINTF("PWM: F%08luHz: %u%% on GPT%u-%u\n", freq, duty, timer, ab);
 
+  lpm_register_peripheral(permit_pm1);
+
   gpt_base = PWM_GPTIMER_NUM_TO_BASE(timer);
   gpt_en = GPTIMER_CTL_TAEN;
   gpt_dir = GPTIMER_CTL_TAPWML;
@@ -135,10 +153,10 @@ pwm_enable(uint32_t freq, uint8_t duty, uint8_t timer, uint8_t ab)
   }
 
   /* Get the peripheral clock and equivalent deassert count */
-  interval_load = sys_ctrl_get_io_clock() / freq;
+  interval_load = sys_ctrl_get_sys_clock() / freq;
   duty_count = ((interval_load * duty) + 1) / 100;
 
-  PRINTF("PWM: IO %luHz: %lu %lu\n", sys_ctrl_get_io_clock(),
+  PRINTF("PWM: sys %luHz: %lu %lu\n", sys_ctrl_get_sys_clock(),
          interval_load, duty_count);
 
   /* Set the start value (period), count down */

cpu/cc2538/dev/pwm.h

@@ -47,8 +47,7 @@
  * Depending on the specific needs these limits can be changed to meet a given
  * duty cycle and lower frequencies by using the prescaler (GPTIMER_TnPR).
  *
- * The PWM timer is stopped when dropping below PM0, alternatively you can set
+ * Running a PWM timer prevents the LPM driver from dropping to PM1+.
- * LPM_CONF_MAX_PM to zero, or call lpm_max_pm(0)
  *
  * @{
  *
@@ -78,15 +77,15 @@
 /** \name PWM recommended values respect to peripheral clock frequency
  * @{
  */
-/* Roughly 244 Hz with a 16 MHz IO clock, no prescaler */
+/* Roughly 244 Hz with a 16-MHz system clock, no prescaler */
-#define PWM_SYS_IO_16MHZ_NO_PRES_MIN         0xFFFF
+#define PWM_SYS_16MHZ_NO_PRES_MIN            0xFFFF
-#define PWM_SYS_IO_16MHZ_NO_PRES_MIN_FREQ    244
+#define PWM_SYS_16MHZ_NO_PRES_MIN_FREQ       244
-/* Roughly 1 Hz with a 16 MHz IO clock, to keep frequency parameter in Hz */
+/* Roughly 1 Hz with a 16-MHz system clock, to keep frequency parameter in Hz */
-#define PWM_SYS_IO_16MHZ_PRES_MIN            0x00F42400
+#define PWM_SYS_16MHZ_PRES_MIN               0x00F42400
-#define PWM_SYS_IO_16MHZ_PRES_MIN_FREQ       1
+#define PWM_SYS_16MHZ_PRES_MIN_FREQ          1
 /* Yields 160 KHz at 16 MHz and allows down to 1% (integer) duty cycles */
-#define PWM_SYS_IO_16MHZ_NO_PRES_MAX         100
+#define PWM_SYS_16MHZ_NO_PRES_MAX            100
-#define PWM_SYS_IO_16MHZ_NO_PRES_MAX_FREQ    160000
+#define PWM_SYS_16MHZ_NO_PRES_MAX_FREQ       160000
 /** @} */
 /*---------------------------------------------------------------------------*/
 /** \name PWM driver definitions and configuration values
@@ -107,8 +106,8 @@
 #define PWM_GPTIMER_CFG_SPLIT_MODE           0x04
 #define PWM_DUTY_MAX                         100
 #define PWM_DUTY_MIN                         0
-#define PWM_FREQ_MIN                         PWM_SYS_IO_16MHZ_PRES_MIN_FREQ
+#define PWM_FREQ_MIN                         PWM_SYS_16MHZ_PRES_MIN_FREQ
-#define PWM_FREQ_MAX                         PWM_SYS_IO_16MHZ_NO_PRES_MAX_FREQ
+#define PWM_FREQ_MAX                         PWM_SYS_16MHZ_NO_PRES_MAX_FREQ
 /** @} */
 /*---------------------------------------------------------------------------*/
 /** \name PWM functions

cpu/cc2538/lpm.c

@@ -101,7 +101,7 @@ static uint8_t max_pm;
 #ifdef LPM_CONF_PERIPH_PERMIT_PM1_FUNCS_MAX
 #define LPM_PERIPH_PERMIT_PM1_FUNCS_MAX LPM_CONF_PERIPH_PERMIT_PM1_FUNCS_MAX
 #else
-#define LPM_PERIPH_PERMIT_PM1_FUNCS_MAX 4
+#define LPM_PERIPH_PERMIT_PM1_FUNCS_MAX 5
 #endif
 
 static lpm_periph_permit_pm1_func_t

examples/zolertia/zoul/test-pwm.c

@@ -35,10 +35,6 @@
  * \defgroup remote-test-pwm Test the CC2538 PWM driver
  *
  * Demonstrates the use of the CC2538 PWM driver for the Zolertia's Zoul boards
- * The PWM timer is stopped when dropping below PM0, alternatively you can set
- * LPM_CONF_MAX_PM to zero, or call lpm_max_pm(0).  In this example is not 
- * needed as we disable RDC in the Makefile, and the CC2538 never drops below
- * PM0
  *
  * @{
  *