From 2d451991af7b3a0b1f3b2e683bfd53d1c94e1ceb Mon Sep 17 00:00:00 2001
From: David Sidrane <david_s5@nscdg.com>
Date: Tue, 1 Nov 2016 10:30:22 -1000
Subject: [PATCH] PX4 System change to Remove #ifdefs from the IO timers

   Update the comment, to explain how to achive a different perescale
   value.

   Added PX4_IO_TIMER_ALTERNATE_RATE one board agnostic ifdef
   PX4_IO_TIMER_ALTERNATE_RATE that is non board specific.

   N.B.  I would like to eliminate PX4_IO_TIMER_ALTERNATE_RATE
   as well, but I need crazyflie HW to validate that the startup
   script can just set the rate on the PWM to 3921 fast enough to
   not effect the motors.
---
 src/drivers/stm32/drv_io_timer.c  | 21 +++++++++++----------
 src/drivers/stm32/drv_led_pwm.cpp |  4 ++--
 2 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/src/drivers/stm32/drv_io_timer.c b/src/drivers/stm32/drv_io_timer.c
index 16b662a3c1..1844c04f94 100644
--- a/src/drivers/stm32/drv_io_timer.c
+++ b/src/drivers/stm32/drv_io_timer.c
@@ -379,11 +379,15 @@ static int allocate_channel(unsigned channel, io_timer_channel_mode_t mode)
 
 static int timer_set_rate(unsigned timer, unsigned rate)
 {
-#if defined(CONFIG_ARCH_BOARD_CRAZYFLIE)
-	/* configure the timer to update at 328.125 kHz (recommended) */
-	rARR(timer) = 255;
+#if defined(PX4_IO_TIMER_ALTERNATE_RATE)
+
+	/* Override the rate to a constant that could be provided by the board */
+
+	rARR(timer) = PX4_IO_TIMER_ALTERNATE_RATE;
 #else
+
 	/* configure the timer to update at the desired rate */
+
 	rARR(timer) = 1000000 / rate;
 #endif
 
@@ -432,15 +436,12 @@ int io_timer_init_timer(unsigned timer)
 			rBDTR(timer) = ATIM_BDTR_MOE;
 		}
 
-#if defined(CONFIG_ARCH_BOARD_CRAZYFLIE)
-		/* configure the timer to free-run at timer frequency */
-		rPSC(timer) = 0;
-#else
-		/* configure the timer to free-run at 1MHz */
+		/* If the timer clock source provided as clock_freq is the STM32_APBx_TIMx_CLKIN
+		 * then configure the timer to free-run at 1MHz.
+		 * Otherwize, other frequencies are attainable by adjusting .clock_freq accordingly.
+		 */
 
 		rPSC(timer) = (io_timers[timer].clock_freq / 1000000) - 1;
-#endif
-
 
 		/*
 		 * Note we do the Standard PWM Out init here
diff --git a/src/drivers/stm32/drv_led_pwm.cpp b/src/drivers/stm32/drv_led_pwm.cpp
index 32a365e9d2..ea3dff17b2 100644
--- a/src/drivers/stm32/drv_led_pwm.cpp
+++ b/src/drivers/stm32/drv_led_pwm.cpp
@@ -37,8 +37,9 @@
 *
 */
 
-#include <nuttx/config.h>
+#include <px4_config.h>
 
+#include <board_config.h>
 
 #include <sys/types.h>
 #include <stdint.h>
@@ -60,7 +61,6 @@
 #include <drivers/stm32/drv_io_timer.h>
 
 
-#include <board_config.h>
 
 #if defined(BOARD_HAS_LED_PWM)
 #define REG(_tmr, _reg) (*(volatile uint32_t *)(led_pwm_timers[_tmr].base + _reg))