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设备树学习之（十二）LCD驱动

2017-06-10 07:28 204 查看

转载自：http://blog.csdn.net/lizuobin2/article/details/54743381

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)

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";
};

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[/code]

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     0x04

static 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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标签： tiny4412 linux驱动

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