/*Framebuffer底层硬件操作各接口函数*/
static struct fb_ops my2440fb_ops =
{
.owner = THIS_MODULE,
.fb_check_var = my2440fb_check_var,/*第②步中已实现*/
.fb_set_par = my2440fb_set_par,/*设置fb_info中的参数，主要是LCD的显示模式*/
.fb_blank = my2440fb_blank,/*显示空白(即：LCD开关控制)*/
.fb_setcolreg = my2440fb_setcolreg,/*设置颜色表*/
/*以下三个函数是可选的，主要是提供fb_console的支持，在内核中已经实现，这里直接调用即可*/
.fb_fillrect = cfb_fillrect,/*定义在drivers/video/cfbfillrect.c中*/
.fb_copyarea = cfb_copyarea,/*定义在drivers/video/cfbcopyarea.c中*/
.fb_imageblit = cfb_imageblit,/*定义在drivers/video/cfbimgblt.c中*/
};
/*设置fb_info中的参数，这里根据用户设置的可变参数var调整固定参数fix*/
static int my2440fb_set_par(struct fb_info *fbinfo)
{
/*获得fb_info中的可变参数*/
struct fb_var_screeninfo *var = &fbinfo->var;
/*判断可变参数中的色位模式，根据色位模式来设置色彩模式*/
switch (var->bits_per_pixel)
{
case 32:
case 16:
case 12:/*12BPP时，设置为真彩色(分成红、绿、蓝三基色)*/
fbinfo->fix.visual = FB_VISUAL_TRUECOLOR;
break;
case 1:/*1BPP时，设置为黑白色(分黑、白两种色，FB_VISUAL_MONO01代表黑，FB_VISUAL_MONO10代表白)*/
fbinfo->fix.visual = FB_VISUAL_MONO01;
break;
default:/*默认设置为伪彩色，采用索引颜色显示*/
fbinfo->fix.visual = FB_VISUAL_PSEUDOCOLOR;
break;
}
/*设置fb_info中固定参数中一行的字节数，公式：1行字节数=(1行像素个数*每像素位数BPP)/8 */
fbinfo->fix.line_length = (var->xres_virtual * var->bits_per_pixel) / 8;
/*修改以上参数后，重新激活fb_info中的参数配置(即：使修改后的参数在硬件上生效)*/
my2440fb_activate_var(fbinfo);
return 0;
}
/*重新激活fb_info中的参数配置*/
static void my2440fb_activate_var(struct fb_info *fbinfo)
{
/*获得结构体变量*/
struct my2440fb_var *fbvar = fbinfo->par;
void __iomem *regs = fbvar->lcd_base;
/*获得fb_info可变参数*/
struct fb_var_screeninfo *var = &fbinfo->var;
/*计算LCD控制寄存器1中的CLKVAL值, 根据数据手册中该寄存器的描述，计算公式如下：
* STN屏：VCLK = HCLK / (CLKVAL * 2), CLKVAL要求>= 2
* TFT屏：VCLK = HCLK / [(CLKVAL + 1) * 2], CLKVAL要求>= 0*/
int clkdiv = my2440fb_calc_pixclk(fbvar, var->pixclock) / 2;
/*获得屏幕的类型*/
int type = fbvar->regs.lcdcon1 & S3C2410_LCDCON1_TFT;
if (type == S3C2410_LCDCON1_TFT)
{
/*根据数据手册按照TFT屏的要求配置LCD控制寄存器1-5*/
my2440fb_config_tft_lcd_regs(fbinfo, &fbvar->regs);
--clkdiv;
if (clkdiv < 0)
{
clkdiv = 0;
}
}
else
{
/*根据数据手册按照STN屏的要求配置LCD控制寄存器1-5*/
my2440fb_config_stn_lcd_regs(fbinfo, &fbvar->regs);
if (clkdiv < 2)
{
clkdiv = 2;
}
}
/*设置计算的LCD控制寄存器1中的CLKVAL值*/
fbvar->regs.lcdcon1 |= S3C2410_LCDCON1_CLKVAL(clkdiv);
/*将各参数值写入LCD控制寄存器1-5中*/
writel(fbvar->regs.lcdcon1 & ~S3C2410_LCDCON1_ENVID, regs + S3C2410_LCDCON1);
writel(fbvar->regs.lcdcon2, regs + S3C2410_LCDCON2);
writel(fbvar->regs.lcdcon3, regs + S3C2410_LCDCON3);
writel(fbvar->regs.lcdcon4, regs + S3C2410_LCDCON4);
writel(fbvar->regs.lcdcon5, regs + S3C2410_LCDCON5);
/*配置帧缓冲起始地址寄存器1-3*/
my2440fb_set_lcdaddr(fbinfo);
fbvar->regs.lcdcon1 |= S3C2410_LCDCON1_ENVID,
writel(fbvar->regs.lcdcon1, regs + S3C2410_LCDCON1);
}
/*计算LCD控制寄存器1中的CLKVAL值*/
static unsigned int my2440fb_calc_pixclk(struct my2440fb_var *fbvar, unsigned long pixclk)
{
/*获得LCD的时钟*/
unsigned long clk = clk_get_rate(fbvar->lcd_clock);
/* 像素时钟单位是皮秒，而时钟的单位是赫兹，所以计算公式为：
* Hz -> picoseconds is / 10^-12
*/
unsigned long long div = (unsigned long long)clk * pixclk;
div >>= 12; /* div / 2^12 */
do_div(div, 625 * 625UL * 625); /* div / 5^12, do_div宏定义在asm/div64.h中*/
return div;
}
/*根据数据手册按照TFT屏的要求配置LCD控制寄存器1-5*/
static void my2440fb_config_tft_lcd_regs(const struct fb_info *fbinfo, struct s3c2410fb_hw *regs)
{
const struct my2440fb_var *fbvar = fbinfo->par;
const struct fb_var_screeninfo *var = &fbinfo->var;
/*根据色位模式设置LCD控制寄存器1和5，参考数据手册*/
switch (var->bits_per_pixel)
{
case 1:/*1BPP*/
regs->lcdcon1 |= S3C2410_LCDCON1_TFT1BPP;
break;
case 2:/*2BPP*/
regs->lcdcon1 |= S3C2410_LCDCON1_TFT2BPP;
break;
case 4:/*4BPP*/
regs->lcdcon1 |= S3C2410_LCDCON1_TFT4BPP;
break;
case 8:/*8BPP*/
regs->lcdcon1 |= S3C2410_LCDCON1_TFT8BPP;
regs->lcdcon5 |= S3C2410_LCDCON5_BSWP | S3C2410_LCDCON5_FRM565;
regs->lcdcon5 &= ~S3C2410_LCDCON5_HWSWP;
break;
case 16:/*16BPP*/
regs->lcdcon1 |= S3C2410_LCDCON1_TFT16BPP;
regs->lcdcon5 &= ~S3C2410_LCDCON5_BSWP;
regs->lcdcon5 |= S3C2410_LCDCON5_HWSWP;
break;
case 32:/*32BPP*/
regs->lcdcon1 |= S3C2410_LCDCON1_TFT24BPP;
regs->lcdcon5 &= ~(S3C2410_LCDCON5_BSWP | S3C2410_LCDCON5_HWSWP | S3C2410_LCDCON5_BPP24BL);
break;
default:/*无效的BPP*/
dev_err(fbvar->dev, "invalid bpp %d\n", var->bits_per_pixel);
}
/*设置LCD配置寄存器2、3、4*/
regs->lcdcon2 = S3C2410_LCDCON2_LINEVAL(var->yres - 1) |
S3C2410_LCDCON2_VBPD(var->upper_margin - 1) |
S3C2410_LCDCON2_VFPD(var->lower_margin - 1) |
S3C2410_LCDCON2_VSPW(var->vsync_len - 1);
regs->lcdcon3 = S3C2410_LCDCON3_HBPD(var->right_margin - 1) |
S3C2410_LCDCON3_HFPD(var->left_margin - 1) |
S3C2410_LCDCON3_HOZVAL(var->xres - 1);
regs->lcdcon4 = S3C2410_LCDCON4_HSPW(var->hsync_len - 1);
}
/*根据数据手册按照STN屏的要求配置LCD控制寄存器1-5*/
static void my2440fb_config_stn_lcd_regs(const struct fb_info *fbinfo, struct s3c2410fb_hw *regs)
{
const struct my2440fb_var *fbvar = fbinfo->par;
const struct fb_var_screeninfo *var = &fbinfo->var;
int type = regs->lcdcon1 & ~S3C2410_LCDCON1_TFT;
int hs = var->xres >> 2;
unsigned wdly = (var->left_margin >> 4) - 1;
unsigned wlh = (var->hsync_len >> 4) - 1;
if (type != S3C2410_LCDCON1_STN4)
{
hs >>= 1;
}
/*根据色位模式设置LCD控制寄存器1，参考数据手册*/
switch (var->bits_per_pixel)
{
case 1:/*1BPP*/
regs->lcdcon1 |= S3C2410_LCDCON1_STN1BPP;
break;
case 2:/*2BPP*/
regs->lcdcon1 |= S3C2410_LCDCON1_STN2GREY;
break;
case 4:/*4BPP*/
regs->lcdcon1 |= S3C2410_LCDCON1_STN4GREY;
break;
case 8:/*8BPP*/
regs->lcdcon1 |= S3C2410_LCDCON1_STN8BPP;
hs *= 3;
break;
case 12:/*12BPP*/
regs->lcdcon1 |= S3C2410_LCDCON1_STN12BPP;
hs *= 3;
break;
default:/*无效的BPP*/
dev_err(fbvar->dev, "invalid bpp %d\n", var->bits_per_pixel);
}
/*设置LCD配置寄存器2、3、4, 参考数据手册*/
if (wdly > 3) wdly = 3;
if (wlh > 3) wlh = 3;
regs->lcdcon2 = S3C2410_LCDCON2_LINEVAL(var->yres - 1);
regs->lcdcon3 = S3C2410_LCDCON3_WDLY(wdly) |
S3C2410_LCDCON3_LINEBLANK(var->right_margin / 8) |
S3C2410_LCDCON3_HOZVAL(hs - 1);
regs->lcdcon4 = S3C2410_LCDCON4_WLH(wlh);
}
/*配置帧缓冲起始地址寄存器1-3，参考数据手册*/
static void my2440fb_set_lcdaddr(struct fb_info *fbinfo)
{
unsigned long saddr1, saddr2, saddr3;
struct my2440fb_var *fbvar = fbinfo->par;
void __iomem *regs = fbvar->lcd_base;
saddr1 = fbinfo->fix.smem_start >> 1;
saddr2 = fbinfo->fix.smem_start;
saddr2 += fbinfo->fix.line_length * fbinfo->var.yres;
saddr2 >>= 1;
saddr3 = S3C2410_OFFSIZE(0) | S3C2410_PAGEWIDTH((fbinfo->fix.line_length / 2) & 0x3ff);
writel(saddr1, regs + S3C2410_LCDSADDR1);
writel(saddr2, regs + S3C2410_LCDSADDR2);
writel(saddr3, regs + S3C2410_LCDSADDR3);
}
/*显示空白，blank mode有5种模式，定义在fb.h中，是一个枚举*/
static int my2440fb_blank(int blank_mode, struct fb_info *fbinfo)
{
struct my2440fb_var *fbvar = fbinfo->par;
void __iomem *regs = fbvar->lcd_base;
/*根据显示空白的模式来设置LCD是开启还是停止*/
if (blank_mode == FB_BLANK_POWERDOWN)
{
my2440fb_lcd_enable(fbvar, 0);/*在第②步中定义*/
}
else
{
my2440fb_lcd_enable(fbvar, 1);/*在第②步中定义*/
}
/*根据显示空白的模式来控制临时调色板寄存器*/
if (blank_mode == FB_BLANK_UNBLANK)
{
/*临时调色板寄存器无效*/
writel(0x0, regs + S3C2410_TPAL);
}
else
{
/*临时调色板寄存器有效*/
writel(S3C2410_TPAL_EN, regs + S3C2410_TPAL);
}
return 0;
}
/*设置颜色表*/
static int my2440fb_setcolreg(unsigned regno,unsigned red,unsigned green,unsigned blue,unsigned transp,struct fb_info*fbinfo)
{
unsigned int val;
struct my2440fb_var *fbvar = fbinfo->par;
void __iomem *regs = fbvar->lcd_base;
switch (fbinfo->fix.visual)
{
case FB_VISUAL_TRUECOLOR:
/*真彩色*/
if (regno < 16)
{
u32 *pal = fbinfo->pseudo_palette;
val = chan_to_field(red, &fbinfo->var.red);
val |= chan_to_field(green, &fbinfo->var.green);
val |= chan_to_field(blue, &fbinfo->var.blue);
pal[regno] = val;
}
break;
case FB_VISUAL_PSEUDOCOLOR:
/*伪彩色*/
if (regno < 256)
{
val = (red >> 0) & 0xf800;
val |= (green >> 5) & 0x07e0;
val |= (blue >> 11) & 0x001f;
writel(val, regs + S3C2410_TFTPAL(regno));
/*修改调色板*/
schedule_palette_update(fbvar, regno, val);
}
break;
default:
return 1;
}
return 0;
}
static inline unsigned int chan_to_field(unsigned int chan, struct fb_bitfield *bf)
{
chan &= 0xffff;
chan >>= 16 - bf->length;
return chan << bf->offset;
}
/*修改调色板*/
static void schedule_palette_update(struct my2440fb_var *fbvar, unsigned int regno, unsigned int val)
{
unsigned long flags;
unsigned long irqen;
/*LCD中断挂起寄存器基地址*/
void __iomem *lcd_irq_base = fbvar->lcd_base + S3C2410_LCDINTBASE;
/*在修改中断寄存器值之前先屏蔽中断，将中断状态保存到flags中*/
local_irq_save(flags);
fbvar->palette_buffer[regno] = val;
/*判断调色板是否准备就像*/
if (!fbvar->palette_ready)
{
fbvar->palette_ready = 1;
/*使能中断屏蔽寄存器*/
irqen = readl(lcd_irq_base + S3C24XX_LCDINTMSK);
irqen &= ~S3C2410_LCDINT_FRSYNC;
writel(irqen, lcd_irq_base + S3C24XX_LCDINTMSK);
}
/*恢复被屏蔽的中断*/
local_irq_restore(flags);
}
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