设备树学习之(十二)LCD驱动
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开发板:tiny4412SDK + S702 + 4GB Flash
要移植的内核版本:Linux-4.4.0 (支持device tree)
u-boot版本:友善之臂自带的 U-Boot 2010.12
busybox版本:busybox 1.25
参考:tiny4412LCD驱动加字符显示
1、背光
友善之臂的该款LCD采用了一线触控技术,包括背光控制也集成在一线触控之中,关于背光的控制,在前一篇文章中已经提及,本文重点在于LCD驱动。
2、LCD接口
- 1)Tiny 4412 使用的lcd接口为LCD1
- 2)图片数据信号接口
- B[0:7] : 蓝色数据信号线
- G[0:7] : 绿色数据信号线
- R[0:7] : 红色数据信号线
- 3)时序信号接口
- DEN 数据允许信号
- VSYNC 垂直同步信号
- HSYNC 水平同步信号
- VLCK LCD时钟信号
- 4)一线触控
- XEINT10_OUT
3、图像的构成
- 帧:一幅图像被称为一帧,每帧有多行组成,每行有多个像素点组成
- 像素:
- 1)显示的最小单位
- 2)由若干位的颜色数据来构成,像素越高,则一个像素点所需要的颜色数据越多,能够显示的颜色更广
- 3)一个像素点构成的颜色位数称为像素深度,单位为1BPP 常见的有16BPP/24BPP
4、颜色的量化(颜色<—–>数字)
颜色一般采用RGB标准,通过对红(R)、绿(GREEN),蓝(B)三个颜色以及相互叠加获取各种不同的颜色
- 1)通过对颜色的编码来对颜色进行量化(即转换成数字量,RGB是一种编码方式)
- 2)每种颜色根据RGB格式不同,每种颜色的量化位不相同
- 3) 常见的RGB格式有RGB565/RGB888
- RGB565: red :5 green : 6 blue:5
- RGB888: red :8 green : 8 blue:8
5、显示图像与LCD时序
- 1)使用HSYNC信号来控制一行的显示
- 2)使用VSYNC信号来控制一帧的显示
- 3)使用VCLK信号来控制一个像素的显示
- 4)使用VDEN信号来控制数据的输出
6、Exyons 4412 display 控制器
- 1)alpha,alpha操作用于实现图形渐变效果,以及半透明效果
- 0xfff == 全透明
- 0x0 == 不透明
- 2)colorkey,colorkey操作在融合两个窗口时过虑掉其中一个窗口的某一种特定颜色
- 3)HOZVAL与LINEVAL
- HOZVAL = (Horizontal display size) - 1
- LINEVAL = (Vertical display size) - 1
- 4)LCD时序图
notes:
.Using the display controller data, you can select one of the above data paths by setting LCDBLK_CFG Register(0x1001_0210). For more information, refer to the “System Others” manual
7、Exyons 4412 display 控制器配置
- 1)gpio配置,查看原理图 ,获取LCD接口的对应的gpio
- LCD_HSYNC:GPF0_0
- LCD_VSYNC:GPF0_1
- LCD_VDEV: GPF0_2
- LCD_VCLK: GPF0_3
- VD[23:0]:GPF1_0 - GPF1_5 / GPF2_0 - GPF2_7 / GPF3_0 - GPF3_3
- 2)时钟配置
- (1)查看Exyons 4412 手册 获取LCD时钟源
LCD 时钟源为SCLKmpll_user_t:800Mhz - (2)配置相关的寄存器得到LCD所需要的时钟 (见07lcd_clock)
- (1)查看Exyons 4412 手册 获取LCD时钟源
- 3)系统配置
LCDBLK_CFG : 配置成FIMD接口
一、设备树
&pinctrl_0 { lcd_demo: lcd{ samsung,pins = "gpf0-0", "gpf0-1", "gpf0-2", "gpf0-3", "gpf0-4", "gpf0-5", "gpf0-6","gpf0-7", "gpf1-0", "gpf1-1", "gpf1-2", "gpf1-3", "gpf1-4", "gpf1-5", "gpf1-6","gpf1-7", "gpf2-0", "gpf2-1", "gpf2-2", "gpf2-3", "gpf2-4", "gpf2-5", "gpf2-6","gpf2-7", "gpf3-0", "gpf3-1", "gpf3-2", "gpf3-3"; samsung,pin-function = <2>; samsung,pin-pud = <0>; samsung,pin-drv = <0>; };}; lcd_demo@11C00000{ compatible = "tiny4412,lcd_demo"; reg = <0x11C00000 0x20c0 0x10010210 0x08 0x10023c80 0x04 0x1003c000 0x1000>; pinctrl-names = "default"; pinctrl-0 = <&lcd_demo>; clocks = <&clock CLK_FIMD0 &clock CLK_ACLK160>; clock-names = "fimd0","aclk160"; };
二、驱动代码
#include <linux/module.h>#include <linux/kernel.h>#include <linux/errno.h>#include <linux/string.h>#include <linux/mm.h>#include <linux/slab.h>#include <linux/delay.h>#include <linux/fb.h>#include <linux/init.h>#include <linux/dma-mapping.h>#include <linux/interrupt.h>#include <linux/workqueue.h>#include <linux/wait.h>#include <linux/platform_device.h>#include <linux/clk.h>#include <asm/io.h>#include <asm/uaccess.h>#include <asm/div64.h>#include <asm/mach/map.h>#include <linux/fb.h>#include <asm/types.h>#define VIDCON0 0x00#define VIDCON1 0x04#define VIDTCON0 0x10#define VIDTCON1 0x14#define VIDTCON2 0x18#define WINCON0 0x20#define VIDOSD0C 0x48#define SHADOWCON 0x34#define WINCHMAP2 0x3c#define VIDOSD0A 0x40#define VIDOSD0B 0x44#define VIDW00ADD0B0 0xA0#define VIDW00ADD1B0 0xD0#define CLK_SRC_LCD0 0x234#define CLK_SRC_MASK_LCD 0x334#define CLK_DIV_LCD 0x534#define CLK_GATE_IP_LCD 0x934#define LCDBLK_CFG 0x00#define LCDBLK_CFG2 0x04static int s3c_lcdfb_setcolreg(unsigned int regno, unsigned int red, unsigned int green, unsigned int blue, unsigned int transp, struct fb_info *info);static struct fb_ops s3c_lcdfb_ops ={ .owner = THIS_MODULE, .fb_setcolreg = s3c_lcdfb_setcolreg, .fb_fillrect = cfb_fillrect, .fb_copyarea = cfb_copyarea, .fb_imageblit = cfb_imageblit,};static struct fb_info *s3c_lcd;static volatile void __iomem *lcd_regs_base;static volatile void __iomem *clk_regs_base;static volatile void __iomem *lcdblk_regs_base;static volatile void __iomem *lcd0_configuration;static u32 pseudo_palette[16];static struct resource *res1, *res2, *res3, *res4;/* from pxafb.c */static inline unsigned int chan_to_field(unsigned int chan, struct fb_bitfield *bf){ chan &= 0xffff; chan >>= 16 - bf->length; return chan << bf->offset;}static int s3c_lcdfb_setcolreg(unsigned int regno, unsigned int red, unsigned int green, unsigned int blue, unsigned int transp, struct fb_info *info){ unsigned int val; if (regno > 16) { return 1; } /* 用red,green,blue三原色构造出val */ val = chan_to_field(red, &info->var.red); val |= chan_to_field(green, &info->var.green); val |= chan_to_field(blue, &info->var.blue); //((u32 *)(info->pseudo_palette))[regno] = val; pseudo_palette[regno] = val; return 0;}static int lcd_probe(struct platform_device *pdev){ int ret; unsigned int temp; /* 1. 分配一个fb_info */ s3c_lcd = framebuffer_alloc(0, NULL); /* 2. 设置 */ /* 2.1 设置 fix 固定的参数 */ strcpy(s3c_lcd->fix.id, "mylcd"); s3c_lcd->fix.smem_len = 480 * 800 * 16 / 8; //显存的长度 s3c_lcd->fix.type = FB_TYPE_PACKED_PIXELS; //类型 s3c_lcd->fix.visual = FB_VISUAL_TRUECOLOR; //TFT 真彩色 s3c_lcd->fix.line_length = 800 * 2; //一行的长度 /* 2.2 设置 var 可变的参数 */ s3c_lcd->var.xres = 800; //x方向分辨率 s3c_lcd->var.yres = 480; //y方向分辨率 s3c_lcd->var.xres_virtual = 800; //x方向虚拟分辨率 s3c_lcd->var.yres_virtual = 480; //y方向虚拟分辨率 s3c_lcd->var.bits_per_pixel = 16; //每个像素占的bit /* RGB:565 */ s3c_lcd->var.red.offset = 11; //红 s3c_lcd->var.red.length = 5; s3c_lcd->var.green.offset = 5; //绿 s3c_lcd->var.green.length = 6; s3c_lcd->var.blue.offset = 0; //蓝 s3c_lcd->var.blue.length = 5; s3c_lcd->var.activate = FB_ACTIVATE_NOW; /* 2.3 设置操作函数 */ s3c_lcd->fbops = &s3c_lcdfb_ops; /* 2.4 其他的设置 */ s3c_lcd->pseudo_palette = pseudo_palette; //调色板 //s3c_lcd->screen_base = ; //显存的虚拟地址,分配显存时填充 s3c_lcd->screen_size = 480 * 800 * 16 / 8; //显存大小 /* 3. 硬件相关的操作 */ /* 3.1 配置GPIO用于LCD */ //设备树中使用"default" /* 3.2 根据LCD手册设置LCD控制器, 比如VCLK的频率等 */ //寄存器映射 res1 = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (res1 == NULL) { printk("platform_get_resource error\n"); return -EINVAL; } lcd_regs_base = devm_ioremap_resource(&pdev->dev, res1); if (lcd_regs_base == NULL) { printk("devm_ioremap_resource error\n"); return -EINVAL; } res2 = platform_get_resource(pdev, IORESOURCE_MEM, 1); if (res2 == NULL) { printk("platform_get_resource error\n"); return -EINVAL; } lcdblk_regs_base = devm_ioremap_resource(&pdev->dev, res2); if (lcdblk_regs_base == NULL) { printk("devm_ioremap_resource error\n"); return -EINVAL; } res3 = platform_get_resource(pdev, IORESOURCE_MEM, 2); if (res3 == NULL) { printk("platform_get_resource error\n"); return -EINVAL; } lcd0_configuration = ioremap(res3->start, 0x04); *lcd0_configuration = 0x07; res4 = platform_get_resource(pdev, IORESOURCE_MEM, 3); if (res4 == NULL) { printk("platform_get_resource error\n"); return -EINVAL; } clk_regs_base = ioremap(res4->start, 0x1000); if (clk_regs_base == NULL) { printk("devm_ioremap_resource error\n"); return -EINVAL; } //使能时钟 //时钟源选择 0110 SCLKMPLL_USER_T 800M temp = readl(clk_regs_base + CLK_SRC_LCD0); temp &= ~0x0f; temp |= 0x06; writel(temp, clk_regs_base + CLK_SRC_LCD0); //FIMD0_MASK temp = readl(clk_regs_base + CLK_SRC_MASK_LCD); temp |= 0x01; writel(temp, clk_regs_base + CLK_SRC_MASK_LCD); //SCLK_FIMD0 = MOUTFIMD0/(FIMD0_RATIO + 1),分频 1/1 temp = readl(clk_regs_base + CLK_DIV_LCD); temp &= ~0x0f; writel(temp, clk_regs_base + CLK_DIV_LCD); //CLK_FIMD0 Pass temp = readl(clk_regs_base + CLK_GATE_IP_LCD); temp |= 0x01; writel(temp, clk_regs_base + CLK_GATE_IP_LCD); //FIMDBYPASS_LBLK0 FIMD Bypass temp = readl(lcdblk_regs_base + LCDBLK_CFG); temp |= 1 << 1; writel(temp, lcdblk_regs_base + LCDBLK_CFG); temp = readl(lcdblk_regs_base + LCDBLK_CFG2); temp |= 1 << 0; writel(temp, lcdblk_regs_base + LCDBLK_CFG2); mdelay(1000); //分频 800/(23 +1 ) == 33M temp = readl(lcd_regs_base + VIDCON0); temp |= (23 << 6); writel(temp, lcd_regs_base + VIDCON0); /* * VIDTCON1: * [5]:IVSYNC ===> 1 : Inverted(反转) * [6]:IHSYNC ===> 1 : Inverted(反转) * [7]:IVCLK ===> 1 : Fetches video data at VCLK rising edge (下降沿触发) * [10:9]:FIXVCLK ====> 01 : VCLK running */ temp = readl(lcd_regs_base + VIDCON1); temp |= (1 << 9) | (1 << 7) | (1 << 5) | (1 << 6); writel(temp, lcd_regs_base + VIDCON1); /* * VIDTCON0: * [23:16]: VBPD + 1 <------> tvpw (1 - 20) 13 * [15:8] : VFPD + 1 <------> tvfp 22 * [7:0] : VSPW + 1 <------> tvb - tvpw = 23 - 13 = 10 */ temp = readl(lcd_regs_base + VIDTCON0); temp |= (12 << 16) | (21 << 8) | (9); writel(temp, lcd_regs_base + VIDTCON0); /* * VIDTCON1: * [23:16]: HBPD + 1 <------> thpw (1 - 40) 36 * [15:8] : HFPD + 1 <------> thfp 210 * [7:0] : HSPW + 1 <------> thb - thpw = 46 - 36 = 10 */ temp = readl(lcd_regs_base + VIDTCON1); temp |= (35 << 16) | (209 << 8) | (9); writel(temp, lcd_regs_base + VIDTCON1); /* * HOZVAL = (Horizontal display size) - 1 and LINEVAL = (Vertical display size) - 1. * Horizontal(水平) display size : 800 * Vertical(垂直) display size : 480 */ temp = (479 << 11) | 799; writel(temp, lcd_regs_base + VIDTCON2); /* * WINCON0: * [16]:Specifies Half-Word swap control bit. 1 = Enables swap P1779 低位像素存放在低字节 * [5:2]: Selects Bits Per Pixel (BPP) mode for Window image : 0101 ===> 16BPP RGB565 * [1]:Enables/disables video output 1 = Enables */ temp = readl(lcd_regs_base + WINCON0); temp |= (1 << 16) | (5 << 2) | 1; writel(temp, lcd_regs_base + WINCON0); temp = readl(lcd_regs_base + SHADOWCON); writel(temp | 0x01, lcd_regs_base + SHADOWCON); //p1769 temp = readl(lcd_regs_base + WINCHMAP2); temp &= ~(7 << 16); temp |= 1 << 16; temp &= ~7; temp |= 1; writel(temp, lcd_regs_base + WINCHMAP2); /* * bit0-10 : 指定OSD图像左上像素的垂直屏幕坐标 * bit11-21: 指定OSD图像左上像素的水平屏幕坐标 */ writel(0, lcd_regs_base + VIDOSD0A); /* * bit0-10 : 指定OSD图像右下像素的垂直屏幕坐标 * bit11-21: 指定OSD图像右下像素的水平屏幕坐标 */ writel((799 << 11) | 479, lcd_regs_base + VIDOSD0B); //Window Size For example, Height ? Width (number of word) temp = 480 * 800 >> 1; writel(temp, lcd_regs_base + VIDOSD0C); /* 3.3 分配显存(framebuffer), 并把地址告诉LCD控制器 */ // s3c_lcd->screen_base 显存虚拟地址 // s3c_lcd->fix.smem_len 显存大小,前面计算的 // s3c_lcd->fix.smem_start 显存物理地址 s3c_lcd->screen_base = dma_alloc_writecombine(NULL, s3c_lcd->fix.smem_len, (dma_addr_t *)&s3c_lcd->fix.smem_start, GFP_KERNEL); //显存起始地址 writel(s3c_lcd->fix.smem_start, lcd_regs_base + VIDW00ADD0B0); //显存结束地址 writel(s3c_lcd->fix.smem_start + s3c_lcd->fix.smem_len, lcd_regs_base + VIDW00ADD1B0); //Enables video output and logic immediately temp = readl(lcd_regs_base + VIDCON0); writel(temp | 0x03, lcd_regs_base + VIDCON0); /* 4. 注册 */ ret = register_framebuffer(s3c_lcd); return ret;}static int lcd_remove(struct platform_device *pdev){ printk("%s enter.\n", __func__); unregister_framebuffer(s3c_lcd); dma_free_writecombine(NULL, s3c_lcd->fix.smem_len, s3c_lcd->screen_base, s3c_lcd->fix.smem_start); framebuffer_release(s3c_lcd); iounmap(lcd0_configuration); iounmap(clk_regs_base); return 0;}static const struct of_device_id lcd_dt_ids[] ={ { .compatible = "tiny4412,lcd_demo", }, {},};MODULE_DEVICE_TABLE(of, lcd_dt_ids);static struct platform_driver lcd_driver ={ .driver = { .name = "lcd_demo", .of_match_table = of_match_ptr(lcd_dt_ids), }, .probe = lcd_probe, .remove = lcd_remove,};static int lcd_init(void){ int ret; printk("enter %s\n", __func__); ret = platform_driver_register(&lcd_driver); if (ret) { printk(KERN_ERR "pwm demo: probe faipwm: %d\n", ret); } return ret;}static void lcd_exit(void){ printk("enter %s\n", __func__); platform_driver_unregister(&lcd_driver);}module_init(lcd_init);module_exit(lcd_exit);MODULE_LICENSE("GPL");
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