pkg: u8g2: add graphics library

pkg/u8g2/Makefile

@@ -0,0 +1,10 @@
+PKG_NAME=u8g2
+PKG_URL=https://github.com/olikraus/u8g2
+PKG_VERSION=4c7ecf099e766b9c678d3453d6b932c8290bdb6b
+
+.PHONY: all
+
+all: git-download
+	"$(MAKE)" -C $(PKG_BUILDDIR)
+
+include $(RIOTBASE)/pkg/pkg.mk

pkg/u8g2/Makefile.include

@@ -0,0 +1,6 @@
+INCLUDES += -I$(BINDIRBASE)/pkg/$(BOARD)/u8g2/csrc
+
+# Link SDL if enabled.
+ifneq (,$(filter u8g2_sdl,$(USEMODULE)))
+  LINKFLAGS += `sdl-config --libs`
+endif

pkg/u8g2/README.md

@@ -0,0 +1,63 @@
+# U8g2
+
+## Introduction
+[U8g2](https://github.com/olikraus/u8g2) is a monochrome graphics library for LCDs and OLEDs. It contains both drivers and high-level drawing routines.
+
+The library is originally written for Arduino boards, but it runs just fine on other platforms, as long as the right drivers are available.
+
+## Usage
+Just put `USEPKG += u8g2` in your Makefile and `#include "u8g2.h"` to your code. Refer to the [U8g2 wiki](https://github.com/olikraus/u8g2/wiki) for more information on the API.
+
+## RIOT-OS interface
+This package patches the original source to add an interface for RIOT-OS.
+
+The following two callbacks add support for the included drivers via I2C and SPI peripherals:
+
+* `u8x8_byte_riotos_hw_spi`
+* `u8x8_byte_riotos_hw_i2c`
+
+For timing and GPIO related operations, the following callback is available.
+
+* `u8x8_gpio_and_delay_riotos`
+
+U8g2 needs to map pin numbers to RIOT-OS pin numbers. It also needs to know which peripheral to use. The following two methods can be used to set this information.
+
+* `u8g2_SetPins(u8g2_dev, pins, bitmap)`
+* `u8g2_SetDevice(u8g2_dev, dev)`
+
+Note: `pins` should point to `gpio_t` array of U8g2 pin numbers to RIOT-OS pins. Due to this, `pins` can take up an additional 100 bytes, because it will use memory for the pins you do not map. You can overcome this limitation by implementing `u8x8_gpio_and_delay_riotos` yourself and hardcode the pins.
+
+### Example
+```
+u8g2_t u8g2;
+
+gpio_t pins[] = {
+    [U8X8_PIN_CS] = GPIO(PA, 0),
+    [U8X8_PIN_DC] = GPIO(PA, 1),
+    [U8X8_PIN_RESET] = GPIO(PA, 2)
+};
+
+uint32_t bitmap = (
+    (1 << U8X8_PIN_CS) +
+    (1 << U8X8_PIN_DC) +
+    (1 << U8X8_PIN_RESET)
+);
+
+u8g2_Setup_ssd1306_128x64_noname_1(&u8g2, U8G2_R0, u8x8_byte_riotos_hw_spi, u8x8_gpio_and_delay_riotos);
+
+u8g2_SetPins(&u8g2, pins, bitmap);
+u8g2_SetDevice(&u8g2, SPI_0);
+```
+
+## Virtual displays
+For targets without an I2C or SPI, virtual displays are available. These displays are part of U8g2, but are not compiled by default.
+
+* By adding `USEMODULE += u8g2_utf8`, a terminal display is used as virtual display, using UTF8 block characters that are printed to stdout.
+* By adding `USEMODULE += u8g2_sdl`, a SDL virtual display will be used. This is only available on native targets that have SDL installed. It uses `sdl-config` to find the headers and libraries. Note that RIOT-OS builds 32-bit binaries and requires 32-bit SDL libraries.
+
+### Example
+```
+u8g2_t u8g2;
+
+u8g2_SetupBuffer_Utf8(&u8g2, U8G2_R0);
+```

pkg/u8g2/patches/0001-u8g2-add-riot-os-makefiles.patch

@@ -0,0 +1,76 @@
+From 09dad731ec608609836aae37ab32fbceec8f3eaa Mon Sep 17 00:00:00 2001
+From: Bas Stottelaar <basstottelaar@gmail.com>
+Date: Tue, 24 May 2016 20:17:39 +0200
+Subject: [PATCH 1/2] u8g2: add riot-os makefiles.
+
+---
+ Makefile                 | 22 ++++++++++++++++++++++
+ csrc/Makefile            |  3 +++
+ sys/sdl/common/Makefile  |  5 +++++
+ sys/utf8/common/Makefile |  3 +++
+ 4 files changed, 33 insertions(+)
+ create mode 100644 Makefile
+ create mode 100644 csrc/Makefile
+ create mode 100644 sys/sdl/common/Makefile
+ create mode 100644 sys/utf8/common/Makefile
+
+diff --git a/Makefile b/Makefile
+new file mode 100644
+index 0000000..ec64fab
+--- /dev/null
++++ b/Makefile
+@@ -0,0 +1,22 @@
++DIRS += csrc
++
++# SDL can be used as a virtual display, but is for native target only.
++ifneq (,$(filter u8g2_sdl,$(USEMODULE)))
++  DIRS += sys/sdl/common
++endif
++
++# UTF8 virtual display is not part of core. Therefore it is a separate module.
++ifneq (,$(filter u8g2_utf8,$(USEMODULE)))
++  DIRS += sys/utf8/common
++endif
++
++# Compiling U8g2 will generate a lot of compiler warnings, which are treated
++# as errors. For the sake of simplicity, ignore them.
++CFLAGS += -Wno-empty-translation-unit \
++          -Wno-newline-eof \
++          -Wno-unused-parameter \
++          -Wno-unused \
++          -Wno-overlength-strings \
++          -Wno-pointer-arith
++
++include $(RIOTBASE)/Makefile.base
+diff --git a/csrc/Makefile b/csrc/Makefile
+new file mode 100644
+index 0000000..1023a87
+--- /dev/null
++++ b/csrc/Makefile
+@@ -0,0 +1,3 @@
++MODULE = u8g2
++
++include $(RIOTBASE)/Makefile.base
+diff --git a/sys/sdl/common/Makefile b/sys/sdl/common/Makefile
+new file mode 100644
+index 0000000..ce8b90b
+--- /dev/null
++++ b/sys/sdl/common/Makefile
+@@ -0,0 +1,5 @@
++MODULE = u8g2_sdl
++
++CFLAGS += `sdl-config --cflags`
++
++include $(RIOTBASE)/Makefile.base
+diff --git a/sys/utf8/common/Makefile b/sys/utf8/common/Makefile
+new file mode 100644
+index 0000000..32e7913
+--- /dev/null
++++ b/sys/utf8/common/Makefile
+@@ -0,0 +1,3 @@
++MODULE = u8g2_utf8
++
++include $(RIOTBASE)/Makefile.base
+-- 
+2.8.1
+