Add experimental driver for e-ink display

experimental/waveshare_eink/linux_kernel_modules/Kconfig

+#
+# FBWS IMU driver
+#
+
+config FBWS
+	tristate
+	depends on FB
+	select FB_SYS_IMAGEBLIT
+	select FB_DEFERRED_IO
+
+
+
+config RPIFB
+	tristate "Bosch FBWS SPI driver"
+	depends on SPI
+	select FBWS
+	select REGMAP_SPI
+	help
+	  If you say yes here you get support for BMI160 IMU on SPI with
+	  accelerometer, gyroscope and external BMG160 magnetometer.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called bmi160_spi.

experimental/waveshare_eink/linux_kernel_modules/Makefile

+#
+# Makefile for Bosch BMI160 IMU
+#
+obj-$(CONFIG_FBWS) += fb_waveshare_eink.o
+obj-$(CONFIG_RPIFB) += rpifb.o

experimental/waveshare_eink/linux_kernel_modules/README.md

+# mangOH Waveshare E-Ink Linux Framebuffer driver
+
+For integration mangOH Red and Waveshare E-Ink Display
+
+### 1. Download Legato Distribution Source Package from sierra wireless website:
+    Yocto Source (Around 4 GB)
+    The file name is Legato-Dist-Source-mdm9x15-SWI9X15Y_07.13.05.00.tar.bz2
+
+### 2. Extract the downloaded Distribution source package:
+
+    Run command: tar -xvjf Legato-Dist-Source-mdm9x15-SWI9X15Y_07.13.05.00.tar.bz2
+
+### 3. Disable Legato configuration to build Yocto
+
+    Run command: cd yocto
+    Run command: export LEGATO_BUILD=0
+
+### 4. Build Yocto images from source
+
+    Run command: make image_bin
+    If you get the error not found 'serf.h', then follow the steps below, otherwise skip to the next step.
+        Go to directory: cd meta-swi/common/recipes-devtools/
+        create directory: mkdir subversion
+        Put attach file: subversion_1.8.9.bbappend, under directory subversion
+        The full path would be: yocto/meta-swi/common/recipes-devtools/subversion/subversion_1.8.9.bbappend
+        build Yocto images again: make image_bin
+### 5. Set environment under yocto directory, this will get command bitbake run:
+
+    Run Command: . ./poky/oe-init-build-env
+    
+### 6. Build Linux kernel with Buffer Frame driver modules support
+
+    Go to directory: yocto/build_bin (cd …/build_bin)
+    Configure kernel with default:
+        Run command: bitbake linux-yocto -c kernel_configme -f
+    Configure kernel to add BT driver module in Linux configuration
+        Run command: bitbake linux-yocto -c menuconfig
+        Enter Device Driver -> Graphic Support
+        Enter <M> Suport for frameBuffer devices
+            <M> Ion Memory Manager
+            <> Lowlevel video output switch controls
+            <*> Support for frame buffer devices 
+                 [*] Enable firmware EDID
+                 [*] Framebuffer foreign endianess support --->
+                 -*- Enable Video Mode Hangling Helper
+                 [*] Enable Tile Blitting Support
+                     ***Frame buffer hardware drivers***
+                 <M> OpenCores VGA/LCD core 2.0 framebuffer support
+                 <M> Epson S1D13XXX framebuffer support
+                 <M> Toshiba Mobile IO framebuffer support
+                 [*] tmiofb acceleration (NEW)
+                 <M> SMSC UFX6000/7000 USB Framebuffer support
+                 <M> Displaylink USB Framebuffer support
+                 <M> Goldfish Framebuffer 
+                 <M> Vitrual Frame Buffer support(ONLY FOR TESTING)
+                 <M> E-Ink Metronome/8track controller support
+                 <M> MSM Framebuffer support
+                 <M> E-Ink Broadsheet/Epson S1D13521 controller support
+                 <M> AUO-K190X EPD controller support
+                    <M> AUO-K1900 EPD controller support
+                    <M> AUO-K190X\1 EPD controller support
+                 [*] Simple framebuffer support 
+        [*] Esynos Video driver support 
+            Console display driver support 
+            <*> Framebuffer Console support
+            [*]     Map the console to primary display device
+            [*]     Framebuffer Console Rotation
+    Exit and save Frame Buffer Linux config
+    Rebuild kernel image: bitbake -f linux-yocto
+ 
+ ### 7. Rebuild rootfs filesystem and images
+    
+    bitbake -c cleansstate mdm9x15-image-minimal
+    bitbake mdm9x15-image-minimal
+
+Check new build CWE images: yocto_wp85.cwe
+
+    Go to images directory: cd build_bin/tmp/deploy/images/swi-mdm9x15
+
+Reflash new image with Frame Buffer driver module support to the target board
+
+    on Windows: FDT command: fdt yocto_wp85.cwe 
+    on Linux: by command: fwupdate download yocto_wp85.cwe
+
+
+
+

experimental/waveshare_eink/linux_kernel_modules/TODO.md

+# Waveshare E-Ink Driver TODO
+
+## Questions
+What is the purpose of the `#ifdef __LITTLE_ENDIAN` sections in the driver? Add code comments to
+clarify.
+
+
+## Fixes Requested
+* I think `eink_device->max_speed_hz` is still being initialized incorrectly. It should be
+  initialized with the max speed supported by the device, not the max speed supported by the SPI
+  master.
+
+
+## Enhancements Requested
+
+
+## Challenges
+How should we deal with the fact that this driver depends on features of the kernel that aren't
+explicitly selectable using menuconfig? I doubt the system reference team would be happy about us
+enabling config for a bunch of device drivers for devices that we don't intend to use so that the
+side-effect of getting `sys_imageblit()` (for example) included into the kernel is achieved.

experimental/waveshare_eink/linux_kernel_modules/fb_waveshare_eink.h

+#ifndef FB_WAVESHARE_EINK_H
+#define FB_WAVESHARE_EINK_H
+
+struct waveshare_eink_platform_data {
+	int rst_gpio;
+	int dc_gpio;
+	int busy_gpio;
+};
+
+#endif /* FB_WAVESHARE_EINK_H */

experimental/waveshare_eink/linux_kernel_modules/fb_waveshare_eink.mdef

+sources:
+{
+    fb_waveshare_eink.c
+}
+
+cflags:
+{
+    // -DDEBUG
+}
+
+params:
+{
+}
+
+load: manual

experimental/waveshare_eink/linux_kernel_modules/mangOH_red_ws213.c

+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include "fb_waveshare_eink.h"
+
+#define SPI_BUS		32766
+#define SPI_BUS_CS1	1
+#define SPI_BUS_SPEED	12000000
+
+const char eink_device_name[] = "waveshare_213";
+static struct spi_device *eink_device;
+
+#if defined(CONFIG_ARCH_MSM9615)
+#define CF3_GPIO22	(49)
+#define CF3_GPIO23	(54)
+#define CF3_GPIO24	(61)
+#elif defined(CONFIG_ARCH_MDM9607)
+#define CF3_GPIO22	 (9)
+#define CF3_GPIO23	(10)
+#define CF3_GPIO24	(11)
+#endif
+
+static struct waveshare_eink_platform_data ws213_pdata = {
+	.rst_gpio	= CF3_GPIO23,
+	.dc_gpio	= CF3_GPIO22,
+	.busy_gpio	= CF3_GPIO24,
+};
+
+static int __init add_ws213fb_device_to_bus(void)
+{
+	struct spi_master *spi_master;
+	int status = 0;
+
+	spi_master = spi_busnum_to_master(SPI_BUS);
+	if (!spi_master) {
+		printk(KERN_ALERT "spi_busnum_to_master(%d) returned NULL\n",
+			SPI_BUS);
+		return -1;
+	}
+
+	eink_device = spi_alloc_device(spi_master);
+	if (!eink_device) {
+		put_device(&spi_master->dev);
+		printk(KERN_ALERT "spi_alloc_device() failed\n");
+		status = -1;
+		goto put_master;
+	}
+
+	eink_device->chip_select = SPI_BUS_CS1;
+	eink_device->max_speed_hz = SPI_BUS_SPEED;
+	eink_device->mode = SPI_MODE_3;
+	eink_device->bits_per_word = 8;
+	eink_device->irq = -1;
+	eink_device->dev.platform_data = &ws213_pdata;
+	eink_device->controller_state = NULL;
+	eink_device->controller_data = NULL;
+	strlcpy(eink_device->modalias, eink_device_name, SPI_NAME_SIZE);
+
+	status = spi_add_device(eink_device);
+	if (status < 0) {
+		spi_dev_put(eink_device);
+		printk(KERN_ALERT "spi_add_device() failed: %d\n", status);
+	}
+
+put_master:
+	put_device(&spi_master->dev);
+
+	return status;
+}
+module_init(add_ws213fb_device_to_bus);
+
+static void __exit exit_ws213fb_device(void)
+{
+	spi_unregister_device(eink_device);
+}
+module_exit(exit_ws213fb_device);
+
+MODULE_AUTHOR("Neil Greatorex");
+MODULE_DESCRIPTION("Bind device driver to SPI ws213 e-ink display");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.1");

experimental/waveshare_eink/linux_kernel_modules/mangOH_red_ws213.mdef

+sources:
+{
+    mangOH_red_ws213.c
+}
+
+cflags:
+{
+    -DCONFIG_FBWS
+    -DCONFIG_RPIFB
+}
+
+params:
+{
+}
+
+load: manual
\ No newline at end of file