efm32: Split efm32/lg into /lg and /common.

Somewhat replaces some earlier work done by hg/lg, but much more
complete, so we kept it as is, because it's bringing in even more parts
after this.

Reviewed-by: Karl Palsson <karlp@tweak.net.au>

lib/efm32/common/timer_common.c

@@ -0,0 +1,62 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2015 Kuldeep Singh Dhaka <kuldeepdhaka9@gmail.com>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libopencm3/efm32/timer.h>
+
+#define HAS_DEAD_TIME_INSERTION(timer) (timer == TIMER0)
+
+/**
+ * Start timer
+ * @param[in] timer Timer (use TIMERx)
+ */
+void timer_start(uint32_t timer)
+{
+	TIMER_CMD(timer) = TIMER_CMD_START;
+}
+
+/**
+ * Stop timer
+ * @param[in] timer Timer (use TIMERx)
+ */
+void timer_stop(uint32_t timer)
+{
+	TIMER_CMD(timer) = TIMER_CMD_STOP;
+}
+
+/** Clock division factor
+ * @param[in] timer Timer (use TIMERx)
+ * @param[in] presc Factor (use TIMER_CTRL_PRESC_DIV*)
+ * @note output-clock = input-clock / @a presc
+ */
+void timer_set_clock_prescaler(uint32_t timer, uint32_t presc)
+{
+	TIMER_CTRL(timer) = (TIMER_CTRL(timer) & ~TIMER_CTRL_PRESC_MASK)
+			    | TIMER_CTRL_PRESC(presc);
+}
+
+/**
+ * Start timer top value
+ * the timer reload after it reaches top value
+ * @param[in] timer Timer (use TIMERx)
+ * @param[in] top Top value
+ */
+void timer_set_top(uint32_t timer, uint32_t top)
+{
+	TIMER_TOP(timer) = top;
+}