Start mvoing hardware drivers to /drivers/ (#1433)

* start driver isolation

* update nyquist and orthodox boards

* update atreus62

* move drivers to avr

* update avr conditional

drivers/avr/analog.h

@@ -0,0 +1,52 @@
+/* Copyright 2015 Jack Humbert
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _analog_h_included__
+#define _analog_h_included__
+
+#include <stdint.h>
+
+void analogReference(uint8_t mode);
+int16_t analogRead(uint8_t pin);
+int16_t adc_read(uint8_t mux);
+
+#define ADC_REF_POWER     (1<<REFS0)
+#define ADC_REF_INTERNAL  ((1<<REFS1) | (1<<REFS0))
+#define ADC_REF_EXTERNAL  (0)
+
+// These prescaler values are for high speed mode, ADHSM = 1
+#if F_CPU == 16000000L
+#define ADC_PRESCALER ((1<<ADPS2) | (1<<ADPS1))
+#elif F_CPU == 8000000L
+#define ADC_PRESCALER ((1<<ADPS2) | (1<<ADPS0))
+#elif F_CPU == 4000000L
+#define ADC_PRESCALER ((1<<ADPS2))
+#elif F_CPU == 2000000L
+#define ADC_PRESCALER ((1<<ADPS1) | (1<<ADPS0))
+#elif F_CPU == 1000000L
+#define ADC_PRESCALER ((1<<ADPS1))
+#else
+#define ADC_PRESCALER ((1<<ADPS0))
+#endif
+
+// some avr-libc versions do not properly define ADHSM
+#if defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB1286__)
+#if !defined(ADHSM)
+#define ADHSM (7)
+#endif
+#endif
+
+#endif