Practice_II_Display: Add framebuffer driver

Signed-off-by: Bekir <[email protected]>

Practice_02-display/lcd_driver/Makefile

@@ -1,12 +1,20 @@
-obj-m += lcd_driver.o
+TARGET = lcd_module
+obj-m += $(TARGET).o
+OBJS = lcd_driver.o fb_lcd.o
+$(TARGET)-objs = $(OBJS)
 
 KERNEL_DIR :=  /home/bekir/Work/LinuxKernelCamp/linux/linux-stable
 
 COMPILE_FLAGS += CROSS_COMPILE=arm-linux-gnueabihf- CROSS=arm-linux-gnueabihf- ARCH=arm
 
 all:
 		make -C $(KERNEL_DIR) M=$(PWD) $(COMPILE_FLAGS) modules
+
+$(TARGET).o: $(OBJS)
+		ld -r -o $@ $(OBJS)
+
 clean:
 		make -C $(KERNEL_DIR) M=$(PWD) $(COMPILE_FLAGS) clean
+
 install:
 		make -C $(KERNEL_DIR) M=$(PWD) modules_install INSTALL_MOD_PATH=$(PWD)/build_modules

Practice_02-display/lcd_driver/fb_lcd.c

@@ -0,0 +1,155 @@
+/*
+ * fb_lcd.c
+ * Author: Bekir Bekirov
+ * Email: [email protected]
+ */
+
+#include "fb_lcd.h"
+#include "lcd_driver.h"
+
+static ssize_t st7735sfb_write(struct fb_info *info, const char __user *buf,
+		size_t count, loff_t *ppos)
+{
+	unsigned long total_size;
+	unsigned long p = *ppos;
+	u8 __iomem *dst;
+
+	total_size = info->fix.smem_len;
+
+	if (p > total_size)
+		return -EINVAL;
+
+	if (count + p > total_size)
+		count = total_size - p;
+
+	if (!count)
+		return -EINVAL;
+
+	dst = (void __force *) (info->screen_base + p);
+
+	if (copy_from_user(dst, buf, count))
+		return -EFAULT;
+
+	lcd_update_screen();
+
+	*ppos += count;
+
+	return count;
+}
+
+static int st7735sfb_blank(int blank_mode, struct fb_info *info)
+{
+	return 0;
+}
+
+static void st7735sfb_fillrect(struct fb_info *info,
+			const struct fb_fillrect *rect)
+{
+	sys_fillrect(info, rect);
+	lcd_update_screen();
+}
+
+static void st7735sfb_copyarea(struct fb_info *info,
+			const struct fb_copyarea *area)
+{
+	sys_copyarea(info, area);
+	lcd_update_screen();
+}
+
+static void st7735sfb_imageblit(struct fb_info *info,
+			const struct fb_image *image)
+{
+	lcd_update_screen();
+}
+
+static int vfb_mmap(struct fb_info *info,
+		    struct vm_area_struct *vma)
+{
+	return remap_vmalloc_range(vma, (void *)info->fix.smem_start,
+							vma->vm_pgoff);
+}
+
+static struct fb_ops st7735sfb_ops = {
+	.owner          = THIS_MODULE,
+	.fb_read        = fb_sys_read,
+	.fb_write       = st7735sfb_write,
+	.fb_blank       = st7735sfb_blank,
+	.fb_fillrect    = st7735sfb_fillrect,
+	.fb_copyarea    = st7735sfb_copyarea,
+	.fb_imageblit   = st7735sfb_imageblit,
+	.fb_mmap		= vfb_mmap,
+};
+
+int init_fb_lcd(struct spi_device *spi)
+{
+	struct lcd_data *ptr_lcddata;
+	int ret;
+	struct fb_info *info;
+	u32 vmem_size;
+	u8 *vmem;
+
+	ptr_lcddata = spi_get_drvdata(spi);
+	info = framebuffer_alloc(0, &spi->dev);
+
+		if (!info)
+			return -ENOMEM;
+
+	pr_info("frame buffer is allocated\n");
+	ptr_lcddata->info = info;
+	ptr_lcddata->width  = ST7735S_WIDTH;
+	ptr_lcddata->height = ST7735S_HEIGHT;
+
+	vmem = (u8 *)(ptr_lcddata->frame_buffer);
+	vmem_size = ptr_lcddata->width * ptr_lcddata->height * 2;
+
+	info->fbops = &st7735sfb_ops;
+	info->fix = st7735sfb_fix;
+	info->fix.line_length = ptr_lcddata->width * 2;
+
+	info->var = st7735sfb_var;
+	info->var.xres = ptr_lcddata->width;
+	info->var.xres_virtual = ptr_lcddata->width;
+	info->var.yres = ptr_lcddata->height;
+	info->var.yres_virtual = ptr_lcddata->height;
+
+	info->var.red.length = 5;
+	info->var.red.offset = 11;
+	info->var.green.length = 6;
+	info->var.green.offset = 5;
+	info->var.blue.length = 5;
+	info->var.blue.offset = 0;
+
+	info->screen_base = (u8 __force __iomem *)vmem;
+	info->fix.smem_start = __pa(vmem);
+	info->fix.smem_len = vmem_size;
+	info->par = NULL;
+	info->flags = FBINFO_FLAG_DEFAULT;
+
+	fb_alloc_cmap(&info->cmap, 256, 0);
+	ptr_lcddata->info = info;
+
+	ret = register_framebuffer(info);
+		if (ret) {
+			pr_info("Error: ret = %d\n", ret);
+			return ret;
+		}
+	pr_info("frame buffer is registered\n");
+	return 0;
+}
+
+int deinit_fb_lcd(struct spi_device *spi)
+{
+	struct lcd_data *ptr_lcddata;
+
+	ptr_lcddata = spi_get_drvdata(spi);
+	unregister_framebuffer(ptr_lcddata->info);
+	fb_dealloc_cmap(&ptr_lcddata->info->cmap);
+	framebuffer_release(ptr_lcddata->info);
+
+	if (!ptr_lcddata)
+		return -ENODEV;
+
+	pr_info("fb is unloaded!\n");
+
+	return 0;
+}

Practice_02-display/lcd_driver/fb_lcd.h

@@ -0,0 +1,37 @@
+#ifndef FB_LCD_H_
+#define FB_LCD_H_
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/delay.h>
+#include <linux/spi/spi.h>
+#include <linux/fb.h>
+#include <linux/uaccess.h>
+
+static struct fb_fix_screeninfo st7735sfb_fix = {
+	.id     	= "ST7735S",
+	.type       = FB_TYPE_PACKED_PIXELS,
+	.visual     = FB_VISUAL_TRUECOLOR,
+	.xpanstep   = 0,
+	.ypanstep   = 0,
+	.ywrapstep  = 0,
+	.accel      = FB_ACCEL_NONE,
+};
+
+
+static struct fb_var_screeninfo st7735sfb_var = {
+	.bits_per_pixel = 16,
+};
+
+#endif /* FB_LCD_H_ */

Practice_02-display/lcd_driver/lcd_driver.c

@@ -1,31 +1,13 @@
-#include "lcd_driver.h"
-
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/device.h>
-#include <linux/err.h>
-#include <linux/kobject.h>
-#include <linux/sysfs.h>
-
-#include <linux/spinlock.h>
-#include <linux/mutex.h>
-#include <linux/of.h>
-#include <linux/of_platform.h>
-#include <linux/platform_device.h>
-#include <linux/gpio.h>
-#include <linux/delay.h>
-#include <linux/spi/spi.h>
-#include <linux/fb.h>
-#include <linux/uaccess.h>
+/*
+ * lcd_driver.c
+ * Author: Bekir Bekirov
+ * Email: [email protected]
+ */
 
 #include "lcd_driver.h"
 
-struct lcd_data {
-	struct spi_device *spi;
-	struct mutex mutex_sysfs;
-	struct fb_info *info;
-	u16 frame_buffer[ST7735S_WIDTH * ST7735S_HEIGHT];
-};
+extern int init_fb_lcd(struct spi_device *spi);
+extern int deinit_fb_lcd(struct spi_device *spi);
 
 static struct lcd_data *lcd_st7735s_data;
 
@@ -162,7 +144,7 @@ static void lcd_set_adr_window(u8 x0, u8 y0, u8 x1, u8 y1)
 	lcd_write_command(ST7735S_RAMWR);
 }
 
-inline void lcd_update_screen(void)
+void lcd_update_screen(void)
 {
 	lcd_write_data((u8 *)lcd_st7735s_data->frame_buffer,
 			sizeof(u16) * ST7735S_WIDTH * ST7735S_HEIGHT);
@@ -171,13 +153,10 @@ inline void lcd_update_screen(void)
 void lcd_draw_pixel(u16 x, u16 y, u16 color)
 {
 	if ((x >= ST7735S_WIDTH) || (y >= ST7735S_HEIGHT))
-			goto out;
+			return;
 
 	lcd_st7735s_data->frame_buffer[x + ST7735S_WIDTH * y] = color;
 	lcd_update_screen();
-
-out:
-	return;
 }
 
 void lcd_fill_rect(u16 x, u16 y, u16 w, u16 h, u16 color)
@@ -186,7 +165,7 @@ void lcd_fill_rect(u16 x, u16 y, u16 w, u16 h, u16 color)
 	u16 j;
 
 	if ((x >= ST7735S_WIDTH) || (y >= ST7735S_HEIGHT))
-			goto out;
+		return;
 
 	if ((x + w - 1) > ST7735S_WIDTH)
 			w = ST7735S_WIDTH - x;
@@ -202,9 +181,6 @@ void lcd_fill_rect(u16 x, u16 y, u16 w, u16 h, u16 color)
 	}
 
 	lcd_update_screen();
-
-out:
-	return;
 }
 
 void lcd_fill_screen(u16 color)
@@ -244,12 +220,16 @@ static int st7735s_probe(struct spi_device *spi)
 	lcd_fill_rect(34, 60, 60, 40, 0x001f);
 	lcd_fill_rect(34, 120, 60, 40, 0xf800);
 
+	if (init_fb_lcd(spi))
+		return -EIO;
+
 	return 0;
 }
 
 static int st7735s_remove(struct spi_device *spi)
 {
 	lcd_st7735s_data = spi_get_drvdata(spi);
+	deinit_fb_lcd(spi);
 
 	if (!lcd_st7735s_data)
 		return -ENODEV;

Practice_02-display/lcd_driver/lcd_driver.h

@@ -1,6 +1,24 @@
 #ifndef ST7735S_TYPES_H
 #define ST7735S_TYPES_H
 
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/delay.h>
+#include <linux/spi/spi.h>
+#include <linux/fb.h>
+#include <linux/uaccess.h>
+
 #define ST7735S_MADCTL_RGB 0x00
 #define ST7735S_MADCTL_BGR 0x08
 #define ST7735S_MADCTL_MY  0x80
@@ -47,4 +65,15 @@
 
 #define ST7735S_DEVICE_NAME "st7735s"
 
+struct lcd_data {
+	struct spi_device *spi;
+	struct mutex mutex_sysfs;
+	struct fb_info *info;
+	u16 frame_buffer[ST7735S_WIDTH * ST7735S_HEIGHT];
+	u32 height;
+	u32 width;
+};
+
+void lcd_update_screen(void);
+
 #endif

Practice_02-display/logs/dmesg

@@ -1,8 +1,13 @@
 root@orangepione:~# dmesg -w
-[ 4452.917936] lcd: device init completed
-[ 4453.028007] lcd: sysfs class created
-[ 4453.028023] lcd: module loaded
-[ 4830.316654] lcd: sysfs class attributes removed
-[ 4830.316739] lcd: sysfs class destroyed
-[ 4830.316885] lcd: module exited
+[21242.825872] lcd: device init completed
+[21242.935524] frame buffer is allocated
+[21242.936153] Console: switching to colour frame buffer device 16x20
+[21243.811276] frame buffer is registered
+[21243.811561] lcd: sysfs class created
+[21243.811573] lcd: module loaded
+[21340.355414] Console: switching to colour dummy device 80x30
+[21347.918165] lcd: sysfs class attributes removed
+[21347.918248] lcd: sysfs class destroyed
+[21347.918553] fb is unloaded!
+[21347.918648] lcd: module exited
 

Practice_02-display/logs/log

@@ -1,11 +1,13 @@
-root@orangepione:/home/bekir# insmod lcd_driver.ko 
-root@orangepione:/home/bekir# echo 0xf800 > /sys/class/lcd_st7735s/fill_screen 
-root@orangepione:/home/bekir# echo 0x001f > /sys/class/lcd_st7735s/fill_screen 
-root@orangepione:/home/bekir# echo 0x03e0 > /sys/class/lcd_st7735s/fill_screen 
-root@orangepione:/home/bekir# echo "30 30 50 50 0x03e0" > /sys/class/lcd_st7735s/fill_rect 
-root@orangepione:/home/bekir# echo "0x03e0 30 30 50 50" > /sys/class/lcd_st7735s/fill_rect 
-root@orangepione:/home/bekir# echo 0x0000 > /sys/class/lcd_st7735s/fill_screen 
-root@orangepione:/home/bekir# echo "0x03e0 30 30 50 50" > /sys/class/lcd_st7735s/fill_rect 
-root@orangepione:/home/bekir# echo "0x03e0 30 30 50 50" > /sys/class/lcd_st7735s/fill_rect 
-root@orangepione:/home/bekir# rmmod lcd_driver 
+root@orangepione:/home/bekir# insmod lcd_module.ko 
+root@orangepione:/home/bekir# ls /dev/
+Display all 642 possibilities? (y or n)
+root@orangepione:/home/bekir# ls /dev/f
+fb0   fd/   full  
+root@orangepione:/home/bekir# ls -l /dev/fb0
+crw-rw---- 1 root video 29, 0 Dec 19 12:10 /dev/fb0
+root@orangepione:/home/bekir# echo 0 > /sys/class/vtconsole/vtcon1/bind
+root@orangepione:/home/bekir# rmmod lcd_module 
+root@orangepione:/home/bekir# ls -l /dev/fb0
+ls: cannot access '/dev/fb0': No such file or directory
 root@orangepione:/home/bekir# 
+