Linux LCD 驱动编写<二>
环境：linux-2.6.32.2，天嵌2440，东华3.5屏
1 #include <linux/module.h> 2 #include <linux/kernel.h> 3 #include <linux/errno.h> 4 #include <linux/string.h> 5 #include <linux/mm.h> 6 #include <linux/slab.h> 7 #include <linux/delay.h> 8 #include <linux/fb.h> 9 #include <linux/init.h> 10 #include <linux/dma-mapping.h> 11 #include <linux/interrupt.h> 12 #include <linux/workqueue.h> 13 #include <linux/wait.h> 14 #include <linux/platform_device.h> 15 #include <linux/clk.h> 16 17 #include <asm/io.h> 18 #include <asm/uaccess.h> 19 #include <asm/div64.h> 20 #include <asm/mach/map.h> 21 22 static int s3c_lcdfb_setcolreg(unsigned int regno, unsigned int red, 23 unsigned int green, unsigned int blue, 24 unsigned int transp, struct fb_info *info); 25 26 struct lcd_regs { 27 unsigned long lcdcon1; 28 unsigned long lcdcon2; 29 unsigned long lcdcon3; 30 unsigned long lcdcon4; 31 unsigned long lcdcon5; 32 unsigned long lcdsaddr1; 33 unsigned long lcdsaddr2; 34 unsigned long lcdsaddr3; 35 unsigned long redlut; 36 unsigned long greenlut; 37 unsigned long bluelut; 38 unsigned long reserved[9]; 39 unsigned long dithmode; 40 unsigned long tpal; 41 unsigned long lcdintpnd; 42 unsigned long lcdsrcpnd; 43 unsigned long lcdintmsk; 44 unsigned long lpcsel; 45 }; 46 47 static struct fb_ops s3c_lcdfb_ops = { 48 .owner = THIS_MODULE, 49 .fb_setcolreg = s3c_lcdfb_setcolreg, 50 .fb_fillrect = cfb_fillrect, 51 .fb_copyarea = cfb_copyarea, 52 .fb_imageblit = cfb_imageblit, 53 }; 54 55 56 static struct fb_info *s3c_lcd; 57 static volatile unsigned long *gpbcon; 58 static volatile unsigned long *gpbdat; 59 static volatile unsigned long *gpccon; 60 static volatile unsigned long *gpdcon; 61 static volatile unsigned long *gpgcon; 62 static volatile struct lcd_regs* lcd_regs; 63 static u32 pseudo_palette[16]; 64 65 66 /* from pxafb.c */ 67 static inline unsigned int chan_to_field(unsigned int chan, struct fb_bitfield *bf) 68 { 69 chan &= 0xffff; 70 chan >>= 16 - bf->length; 71 return chan << bf->offset; 72 } 73 74 75 static int s3c_lcdfb_setcolreg(unsigned int regno, unsigned int red, 76 unsigned int green, unsigned int blue, 77 unsigned int transp, struct fb_info *info) 78 { 79 unsigned int val; 80 81 if (regno > 16) 82 return 1; 83 84 /* 用red,green,blue三原色构造出val */ 85 val = chan_to_field(red, &info->var.red); 86 val |= chan_to_field(green, &info->var.green); 87 val |= chan_to_field(blue, &info->var.blue); 88 89 pseudo_palette[regno] = val; 90 return 0; 91 } 92 93 static int lcd_init(void) 94 { 95 /* 1. 分配一个fb_info */ 96 s3c_lcd = framebuffer_alloc(0, NULL); 97 98 /* 2. 设置 */ 99 /* 2.1 设置固定的参数 */ 100 strcpy(s3c_lcd->fix.id, "mylcd"); 101 s3c_lcd->fix.smem_len = 320*240*16/8; 102 s3c_lcd->fix.type = FB_TYPE_PACKED_PIXELS; 103 s3c_lcd->fix.visual = FB_VISUAL_TRUECOLOR; /* TFT */ 104 s3c_lcd->fix.line_length = 320*2; 105 106 /* 2.2 设置可变的参数 */ 107 s3c_lcd->var.xres = 320; 108 s3c_lcd->var.yres = 240; 109 s3c_lcd->var.xres_virtual = 320; 110 s3c_lcd->var.yres_virtual = 240; 111 s3c_lcd->var.bits_per_pixel = 16; 112 113 /* RGB:565 */ 114 s3c_lcd->var.red.offset = 11; 115 s3c_lcd->var.red.length = 5; 116 117 s3c_lcd->var.green.offset = 5; 118 s3c_lcd->var.green.length = 6; 119 120 s3c_lcd->var.blue.offset = 0; 121 s3c_lcd->var.blue.length = 5; 122 123 s3c_lcd->var.activate = FB_ACTIVATE_NOW; 124 125 126 /* 2.3 设置操作函数 */ 127 s3c_lcd->fbops = &s3c_lcdfb_ops; 128 129 /* 2.4 其他的设置 */ 130 s3c_lcd->pseudo_palette = pseudo_palette; 131 s3c_lcd->screen_size = 320*240*16/8; 132 133 /* 3. 硬件相关的操作 */ 134 /* 3.1 配置GPIO用于LCD */ 135 gpbcon = ioremap(0x56000010, 8); 136 gpbdat = gpbcon+1; 137 gpccon = ioremap(0x56000020, 4); 138 gpdcon = ioremap(0x56000030, 4); 139 gpgcon = ioremap(0x56000060, 4); 140 141 *gpccon = 0xaaaaaaaa; /* GPIO管脚用于VD[7:0],LCDVF[2:0],VM,VFRAME,VLINE,VCLK,LEND */ 142 *gpdcon = 0xaaaaaaaa; /* GPIO管脚用于VD[23:8] */ 143 *gpgcon |= (3<<8); /* GPG4用作LCD_PWREN */ 144 145 /* 3.2 根据LCD手册设置LCD控制器, 比如VCLK的频率等 */ 146 lcd_regs = ioremap(0x4D000000, sizeof(struct lcd_regs)); 147 148 /* bit[17:8]: VCLK = HCLK / [(CLKVAL+1) x 2] 149 * bit[6:5]: 0b11, TFT LCD 150 * bit[4:1]: 0b1100, 16 bpp for TFT 151 * bit[0] : 0 = Disable the video output and the LCD control signal. 152 */ 153 lcd_regs->lcdcon1 = (9<<8) | (3<<5) | (0x0c<<1); 154 155 /* 垂直方向的时间参数 156 * bit[31:24]: VBPD, VSYNC之后再过多长时间才能发出第1行数据 157 * 158 * bit[23:14]: 多少行, 159 * bit[13:6] : VFPD, 发出最后一行数据之后，再过多长时间才发出VSYNC 160 * 161 * bit[5:0] : VSPW, VSYNC信号的脉冲宽度, 162 */ 163 lcd_regs->lcdcon2 = (15<<24) | (240<<14) | (12<<6) | (3<<0); 164 165 166 /* 水平方向的时间参数 167 * bit[25:19]: HBPD, VSYNC之后再过多长时间才能发出第1行数据 168 * 169 * 170 * bit[18:8]: 多少列, 171 * 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 172 * 173 */ 174 lcd_regs->lcdcon3 = (38<<19) | (320<<8) | (20<<0); 175 176 /* 水平方向的同步信号 177 * bit[7:0] : HSPW, HSYNC信号的脉冲宽度 178 */ 179 lcd_regs->lcdcon4 = 30; 180 181 /* 信号的极性 182 * bit[11]: 1=565 format 183 * bit[10]: 0 = The video data is fetched at VCLK falling edge 184 * bit[9] : 1 = HSYNC信号要反转,即低电平有效 185 * bit[8] : 1 = VSYNC信号要反转,即低电平有效 186 * bit[6] : 0 = VDEN不用反转 187 * bit[3] : 0 = PWREN输出0 188 * bit[1] : 0 = BSWP 189 * bit[0] : 1 = HWSWP 2440手册P413 190 */ 191 lcd_regs->lcdcon5 = (1<<11) | (1<<10) | (1<<9) | (1<<8) | (1<<0); 192 193 /* 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 */ 194 s3c_lcd->screen_base = dma_alloc_writecombine(NULL, s3c_lcd->fix.smem_len, &s3c_lcd->fix.smem_start, GFP_KERNEL); 195 196 lcd_regs->lcdsaddr1 = (s3c_lcd->fix.smem_start >> 1) & ~(3<<30); 197 lcd_regs->lcdsaddr2 = ((s3c_lcd->fix.smem_start + s3c_lcd->fix.smem_len) >> 1) & 0x1fffff; 198 lcd_regs->lcdsaddr3 = (320*16/16); /* 一行的长度(单位: 2字节) */ 199 200 /* 启动LCD */ 201 lcd_regs->lcdcon1 |= (1<<0); /* 使能LCD控制器 */ 202 lcd_regs->lcdcon5 |= (1<<3); /* 使能LCD本身 */ 203 204 /* 4. 注册 */ 205 register_framebuffer(s3c_lcd); 206 207 return 0; 208 } 209 210 static void lcd_exit(void) 211 { 212 unregister_framebuffer(s3c_lcd); 213 lcd_regs->lcdcon1 &= ~(1<<0); /* 关闭LCD本身 */ 214 dma_free_writecombine(NULL, s3c_lcd->fix.smem_len, s3c_lcd->screen_base, s3c_lcd->fix.smem_start); 215 iounmap(lcd_regs); 216 iounmap(gpbcon); 217 iounmap(gpccon); 218 iounmap(gpdcon); 219 iounmap(gpgcon); 220 framebuffer_release(s3c_lcd); 221 } 222 223 module_init(lcd_init); 224 module_exit(lcd_exit); 225 226 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
