first working example utilizing efm32lib

this *does* include hardcoded paths of my local machine; that will be
fixed with the next commits.

examples/efm32/tinygecko/efm32-tg-stk3300/miniblink-efm32lib/Makefile

@@ -0,0 +1,26 @@
+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+## Copyright (C) 2012 chrysn <chrysn@fsfe.org>
+##
+## 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/>.
+##
+
+BINARY = miniblink
+
+OBJS += efm32_gpio.o efm32_cmu.o
+CFLAGS += -I/tmp/EFM32_CMSIS_2.4.1/efm32lib/inc/ -I /tmp/EFM32_CMSIS_2.4.1/CMSIS/CM3/DeviceSupport/EnergyMicro/EFM32/ -DEFM32TG840F32 -I.
+
+include ../Makefile.include

examples/efm32/tinygecko/efm32-tg-stk3300/miniblink-efm32lib/README

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+===================================================
+EFM32-TG-STK3300 Examples miniblink-efm32lib README
+===================================================
+
+This is a port of the miniblink example to the efm32lib library.
+
+It's intended for the EFM32-TG-STK3300 eval board. It should blink the user LED
+on the board, just as the original miniblink example does.
+

examples/efm32/tinygecko/efm32-tg-stk3300/miniblink-efm32lib/core_cm3.h

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+/* the original core_cm3.h is nonfree by arm; this provides libopencm3 variant of the symbols efm32lib needs of CMSIS. */
+#include <stdint.h>
+
+/* needed by system_efm32.h:196, guessing */
+#define __INLINE inline
+
+/* needed around efm32tg840f32.h:229. comparing the efm32lib definitions to the
+ * libopencm3 ones, "volatile" is all that's missing. */
+#define __IO volatile
+#define __O volatile
+#define __I volatile
+
+/* -> style access for what is defined in libopencm3/stm32/f1/scb.h /
+ * cm3/memorymap.h, as it's needed by efm32lib/inc/efm32_emu.h */
+
+/* from stm32/f1/scb.h */
+#define SCB_SCR_SLEEPDEEP_Msk  (1 << 2)
+/* structure as in, for example,
+ * DeviceSupport/EnergyMicro/EFM32/efm32tg840f32.h, data from
+ * libopencm3/stm32/f1/scb.h. incomplete. */
+typedef struct
+{
+	__IO uint32_t CPUID;
+	__IO uint32_t ICSR;
+	__IO uint32_t VTOR;
+	__IO uint32_t AIRCR;
+	__IO uint32_t SCR;
+	__IO uint32_t CCR;
+} SCB_TypeDef;
+#define SCB ((SCB_TypeDef *) SCB_BASE)
+/* from libopencm3/cm3/memorymap.h */
+#define PPBI_BASE                       0xE0000000
+#define SCS_BASE                        (PPBI_BASE + 0xE000)
+#define SCB_BASE                        (SCS_BASE + 0x0D00)
+
+/* needed by efm32_emu.h, guessing and taking the implementation used in
+ * lightswitch-interrupt.c */
+#define __WFI() __asm__("wfi")
+
+/* needed by efm32_cmu.h, probably it's just what gcc provides anyway */
+#define __CLZ(div) __builtin_clz(div)

examples/efm32/tinygecko/efm32-tg-stk3300/miniblink-efm32lib/efm32_cmu.c

@@ -0,0 +1 @@
+/tmp/EFM32_CMSIS_2.4.1/efm32lib/src/efm32_cmu.c

examples/efm32/tinygecko/efm32-tg-stk3300/miniblink-efm32lib/efm32_gpio.c

@@ -0,0 +1 @@
+/tmp/EFM32_CMSIS_2.4.1/efm32lib/src/efm32_gpio.c

examples/efm32/tinygecko/efm32-tg-stk3300/miniblink-efm32lib/miniblink.c

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+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+ * Copyright (C) 2012 chrysn <chrysn@fsfe.org>
+ *
+ * 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 <efm32_cmu.h>
+#include <efm32_gpio.h>
+
+void led_setup(void);
+void led_toggle(void);
+
+/** @file
+ * Minimal example for making the User LED of the EFM32-TG-STK330 eval board blink.
+ */
+
+/**
+ * Toggle the User LED in an infinite loop, with time between the toggling
+ * determined by a busy loop stupidly counting up.
+ */
+
+int main(void)
+{
+	int x;
+
+	led_setup();
+
+	while(1) {
+		for(x = 0; x < 200000; ++x) asm("mov r0,r0"); /* no-op, prevent compiler from optimizing this away */
+		led_toggle();
+	};
+}
+
+/**
+ * Enable GPIO, and set up port D7 as an output pin.
+ */
+
+void led_setup(void)
+{
+	// Before GPIO works, according to d0034_efm32tg_reference_manual.pdf
+	// note in section 28.3.7, we'll have to enable GPIO in CMU_HFPERCLKEN0
+	
+	CMU->HFPERCLKEN0 |= _CMU_HFPERCLKEN0_GPIO_MASK;
+
+	// The User LED is connected to PD7 to the plus side of the LED
+	// according to t0011_efm32_tiny_gecko_stk_user_manual.pdf figures 16.2
+	// and 16.3 (called UIF_LED0)
+	
+	GPIO_PinModeSet(gpioPortD, 7, gpioModePushPull, 0);
+}
+
+void led_toggle(void)
+{
+	GPIO_PinOutToggle(gpioPortD, 7);
+}