Add microcontroller.cpu.temperature, for use as a simple sensor on minimal boards. (#211)

* Add microcontroller.cpu, the sole instance of microcontroller.Processor.
microcontroller.cpu.frequency is the clock frequency, in Hz.
microcontroller.cpu.temperature is the reading from the internal temperature sensor, in Celsius. None if not available.

* Squeeze firmware size by using -finline-limit. Otherwise non-Express builds were slightly too big.

* Update submodules.

* Fix documentation glitches

5 files changed, 93 insertions, 1 deletions

diff --git a/esp8266/Makefile b/esp8266/Makefile
index 5c32160cc..3daff9c62 100644
--- a/esp8266/Makefile
+++ b/esp8266/Makefile
@@ -101,6 +101,7 @@ SRC_C = \
 SRC_COMMON_HAL = \
 	microcontroller/__init__.c \
 	microcontroller/Pin.c \
+	microcontroller/Processor.c \
 	analogio/__init__.c \
 	analogio/AnalogIn.c \
 	analogio/AnalogOut.c \
diff --git a/esp8266/common-hal/microcontroller/Processor.c b/esp8266/common-hal/microcontroller/Processor.c
new file mode 100644
index 000000000..fb0a3d50a
--- /dev/null
+++ b/esp8266/common-hal/microcontroller/Processor.c
@@ -0,0 +1,40 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Dan Halbert for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "common-hal/microcontroller/Processor.h"
+
+#include <math.h>
+
+#include "esp_mphal.h"
+
+
+float common_hal_mcu_processor_get_temperature(void) {
+    return NAN;
+}
+
+uint32_t common_hal_mcu_processor_get_frequency(void) {
+    return mp_hal_get_cpu_freq();
+}
diff --git a/esp8266/common-hal/microcontroller/Processor.h b/esp8266/common-hal/microcontroller/Processor.h
new file mode 100644
index 000000000..8fc59c2cb
--- /dev/null
+++ b/esp8266/common-hal/microcontroller/Processor.h
@@ -0,0 +1,37 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Dan  Halbert for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_ESP8266_COMMON_HAL_MICROCONTROLLER_PROCESSOR_H
+#define MICROPY_INCLUDED_ESP8266_COMMON_HAL_MICROCONTROLLER_PROCESSOR_H
+
+#include "py/obj.h"
+
+typedef struct {
+    mp_obj_base_t base;
+    // Stores no state currently.
+} mcu_processor_obj_t;
+
+#endif // MICROPY_INCLUDED_ESP8266_COMMON_HAL_MICROCONTROLLER_PROCESSOR_H
diff --git a/esp8266/common-hal/microcontroller/__init__.c b/esp8266/common-hal/microcontroller/__init__.c
index 4fb5eee63..6aef23761 100644
--- a/esp8266/common-hal/microcontroller/__init__.c
+++ b/esp8266/common-hal/microcontroller/__init__.c
@@ -25,8 +25,10 @@
  */
 
 #include "common-hal/microcontroller/Pin.h"
-#include "common-hal/microcontroller/Pin.h"
+#include "common-hal/microcontroller/Processor.h"
+
 #include "shared-bindings/microcontroller/Pin.h"
+#include "shared-bindings/microcontroller/Processor.h"
 
 #include "eagle_soc.h"
 #include "ets_alt_task.h"
@@ -52,6 +54,14 @@ void common_hal_mcu_enable_interrupts() {
     enable_irq(saved_interrupt_state & ~(1 << ETS_LOOP_ITER_BIT));
 }
 
+// The singleton microcontroller.Processor object, returned by microcontroller.cpu
+// It currently only has properties, and no state.
+mcu_processor_obj_t common_hal_mcu_processor_obj = {
+    .base = {
+        .type = &mcu_processor_type,
+    },
+};
+
 // This macro is used to simplify pin definition in boards/<board>/pins.c
 #define PIN(p_name, p_gpio_number, p_gpio_function, p_peripheral) \
 const mcu_pin_obj_t pin_## p_name = { \
diff --git a/esp8266/esp_mphal.c b/esp8266/esp_mphal.c
index effed04dd..748c90292 100644
--- a/esp8266/esp_mphal.c
+++ b/esp8266/esp_mphal.c
@@ -55,6 +55,10 @@ void mp_hal_delay_us(uint32_t us) {
     }
 }
 
+uint32_t mp_hal_get_cpu_freq(void) {
+    return system_get_cpu_freq() * 1000000;
+}
+
 int mp_hal_stdin_rx_chr(void) {
     for (;;) {
         int c = ringbuf_get(&input_buf);