Linux LCD 驱动编写<二>

环境：linux-2.6.32.2，天嵌2440，东华3.5屏

#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>

static int s3c_lcdfb_setcolreg(unsigned int regno, unsigned int red,
unsigned int green, unsigned int blue,
unsigned int transp, struct fb_info *info);

struct lcd_regs {
unsigned long    lcdcon1;
unsigned long    lcdcon2;
unsigned long    lcdcon3;
unsigned long    lcdcon4;
unsigned long    lcdcon5;
unsigned long    lcdsaddr1;
unsigned long    lcdsaddr2;
unsigned long    lcdsaddr3;
unsigned long    redlut;
unsigned long    greenlut;
unsigned long    bluelut;
unsigned long    reserved[9];
unsigned long    dithmode;
unsigned long    tpal;
unsigned long    lcdintpnd;
unsigned long    lcdsrcpnd;
unsigned long    lcdintmsk;
unsigned long    lpcsel;
};

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 unsigned long *gpbcon;
static volatile unsigned long *gpbdat;
static volatile unsigned long *gpccon;
static volatile unsigned long *gpdcon;
static volatile unsigned long *gpgcon;
static volatile struct lcd_regs* lcd_regs;
static u32 pseudo_palette[16];

/* 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);

pseudo_palette[regno] = val;
return 0;
}

static int lcd_init(void)
{
/* 1. 分配一个fb_info */
s3c_lcd = framebuffer_alloc(0, NULL);

/* 2. 设置 */
/* 2.1 设置固定的参数 */
strcpy(s3c_lcd->fix.id, "mylcd");
s3c_lcd->fix.smem_len = 320*240*16/8;
s3c_lcd->fix.type     = FB_TYPE_PACKED_PIXELS;
s3c_lcd->fix.visual   = FB_VISUAL_TRUECOLOR; /* TFT */
s3c_lcd->fix.line_length = 320*2;

/* 2.2 设置可变的参数 */
s3c_lcd->var.xres           = 320;
s3c_lcd->var.yres           = 240;
s3c_lcd->var.xres_virtual   = 320;
s3c_lcd->var.yres_virtual   = 240;
s3c_lcd->var.bits_per_pixel = 16;

/* RGB:565 */
s3c_lcd->var.red.offset     = 11;
s3c_lcd->var.red.length     = 5;

s3c_lcd->var.green.offset   = 5;
s3c_lcd->var.green.length   = 6;

s3c_lcd->var.blue.offset    = 0;
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;
s3c_lcd->screen_size   = 320*240*16/8;

/* 3. 硬件相关的操作 */
/* 3.1 配置GPIO用于LCD */
gpbcon = ioremap(0x56000010, 8);
gpbdat = gpbcon+1;
gpccon = ioremap(0x56000020, 4);
gpdcon = ioremap(0x56000030, 4);
gpgcon = ioremap(0x56000060, 4);

*gpccon  = 0xaaaaaaaa;   /* GPIO管脚用于VD[7:0],LCDVF[2:0],VM,VFRAME,VLINE,VCLK,LEND */
*gpdcon  = 0xaaaaaaaa;   /* GPIO管脚用于VD[23:8] */
*gpgcon |= (3<<8); /* GPG4用作LCD_PWREN */

/* 3.2 根据LCD手册设置LCD控制器, 比如VCLK的频率等 */
lcd_regs = ioremap(0x4D000000, sizeof(struct lcd_regs));

/* bit[17:8]: VCLK = HCLK / [(CLKVAL+1) x 2]
* bit[6:5]: 0b11, TFT LCD
* bit[4:1]: 0b1100, 16 bpp for TFT
* bit[0]  : 0 = Disable the video output and the LCD control signal.
*/
lcd_regs->lcdcon1  = (9<<8) | (3<<5) | (0x0c<<1);

/* 垂直方向的时间参数
* bit[31:24]: VBPD, VSYNC之后再过多长时间才能发出第1行数据
*
* bit[23:14]: 多少行,
* bit[13:6] : VFPD, 发出最后一行数据之后，再过多长时间才发出VSYNC
*
* bit[5:0]  : VSPW, VSYNC信号的脉冲宽度,
*/
lcd_regs->lcdcon2  = (15<<24) | (240<<14) | (12<<6) | (3<<0);

/* 水平方向的时间参数
* bit[25:19]: HBPD, VSYNC之后再过多长时间才能发出第1行数据
*
*
* bit[18:8]: 多少列,
* bit[7:0] : HFPD, 发出最后一行里最后一个象素数据之后，再过多长时间才发出HSYNC
*
*/
lcd_regs->lcdcon3 = (38<<19) | (320<<8) | (20<<0);

/* 水平方向的同步信号
* bit[7:0]    : HSPW, HSYNC信号的脉冲宽度
*/
lcd_regs->lcdcon4 = 30;

/* 信号的极性
* bit[11]: 1=565 format
* bit[10]: 0 = The video data is fetched at VCLK falling edge
* bit[9] : 1 = HSYNC信号要反转,即低电平有效
* bit[8] : 1 = VSYNC信号要反转,即低电平有效
* bit[6] : 0 = VDEN不用反转
* bit[3] : 0 = PWREN输出0
* bit[1] : 0 = BSWP
* bit[0] : 1 = HWSWP 2440手册P413
*/
lcd_regs->lcdcon5 = (1<<11) | (1<<10) | (1<<9) | (1<<8) | (1<<0);

/* 3.3 分配显存(framebuffer), 并把地址告诉LCD控制器：screen_base是虚拟地址，smem_start是物理地址 */
s3c_lcd->screen_base = dma_alloc_writecombine(NULL, s3c_lcd->fix.smem_len, &s3c_lcd->fix.smem_start, GFP_KERNEL);

lcd_regs->lcdsaddr1  = (s3c_lcd->fix.smem_start >> 1) & ~(3<<30);
lcd_regs->lcdsaddr2  = ((s3c_lcd->fix.smem_start + s3c_lcd->fix.smem_len) >> 1) & 0x1fffff;
lcd_regs->lcdsaddr3  = (320*16/16);  /* 一行的长度(单位: 2字节) */

/* 启动LCD */
lcd_regs->lcdcon1 |= (1<<0); /* 使能LCD控制器 */
lcd_regs->lcdcon5 |= (1<<3); /* 使能LCD本身 */

/* 4. 注册 */
register_framebuffer(s3c_lcd);

return 0;
}

static void lcd_exit(void)
{
unregister_framebuffer(s3c_lcd);
lcd_regs->lcdcon1 &= ~(1<<0); /* 关闭LCD本身 */
dma_free_writecombine(NULL, s3c_lcd->fix.smem_len, s3c_lcd->screen_base, s3c_lcd->fix.smem_start);
iounmap(lcd_regs);
iounmap(gpbcon);
iounmap(gpccon);
iounmap(gpdcon);
iounmap(gpgcon);
framebuffer_release(s3c_lcd);
}

module_init(lcd_init);
module_exit(lcd_exit);

MODULE_LICENSE("GPL");

装载驱动前要把内核自带的lcd驱动去掉，测试时发现这样写还有点问题，可能是上面的硬件设置还有点问题，不过可以使用了，但是当rmmod时不能卸载驱动，显示如下信息：

rmmod: cannot unload 'lcd': Resource temporarily unavailable

如有路过的大侠知道原因麻烦告诉下