initial_pins: Add ability to configure output pins at mcu startup

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/Kconfig

@@ -88,6 +88,15 @@ config STEP_DELAY
         The default for AVR is -1, for all other micro-controllers it
         is 2us.
 
+config INITIAL_PINS
+    string "GPIO pins to set at micro-controller startup"
+    depends on LOW_LEVEL_OPTIONS
+    help
+        One may specify a comma separated list of gpio pins to set
+        during the micro-controller startup sequence. By default the
+        pins will be set to output high - preface a pin with a '!'
+        character to set that pin to output low.
+
 # The HAVE_GPIO_x options allow boards to disable support for some
 # commands if the hardware does not support the feature.
 config HAVE_GPIO

src/Makefile

@@ -1,6 +1,6 @@
 # Main code build rules
 
-src-y += sched.c command.c basecmd.c debugcmds.c
+src-y += sched.c command.c basecmd.c debugcmds.c initial_pins.c
 src-$(CONFIG_HAVE_GPIO) += gpiocmds.c stepper.c endstop.c
 src-$(CONFIG_HAVE_GPIO_ADC) += adccmds.c
 src-$(CONFIG_HAVE_GPIO_SPI) += spicmds.c thermocouple.c

src/initial_pins.c

@@ -0,0 +1,25 @@
+// Support setting gpio pins at mcu start
+//
+// Copyright (C) 2019  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "autoconf.h" // CONFIG_INITIAL_PINS
+#include "board/gpio.h" // gpio_out_setup
+#include "board/pgm.h" // READP
+#include "ctr.h" // DECL_CTR
+#include "initial_pins.h" // initial_pins
+#include "sched.h" // DECL_INIT
+
+DECL_CTR("DECL_INITIAL_PINS " __stringify(CONFIG_INITIAL_PINS));
+
+void
+initial_pins_setup(void)
+{
+    int i;
+    for (i=0; i<initial_pins_size; i++) {
+        const struct initial_pin_s *ip = &initial_pins[i];
+        gpio_out_setup(READP(ip->pin), READP(ip->flags) & IP_OUT_HIGH);
+    }
+}
+DECL_INIT(initial_pins_setup);

src/initial_pins.h

@@ -0,0 +1,15 @@
+#ifndef __INITIAl_PINS_H
+#define __INITIAl_PINS_H
+
+struct initial_pin_s {
+    int pin;
+    uint8_t flags;
+};
+
+enum { IP_OUT_HIGH = 1 };
+
+// out/compile_time_request.c (auto generated file)
+extern const struct initial_pin_s initial_pins[];
+extern const int initial_pins_size;
+
+#endif // initial_pins.h