新路程------imx6 lvds ioctl
最近有个需求，做一些接口给上层应用调用
于是看了一下驱动，linux有一套标准的framebuffer机制让我们做接口，就是fb_ioctl
首先看对应的framebuffer驱动，在之前的ldb.c中，确实配置了对应的fb_info结构体，但是要修改这个结构体的参数并不需要在ldb.c中做，在mxc_ipuv3_fb.c里
static struct fb_ops mxcfb_ops = {
.owner = THIS_MODULE,
.fb_set_par = mxcfb_set_par,
.fb_check_var = mxcfb_check_var,
.fb_setcolreg = mxcfb_setcolreg,
.fb_pan_display = mxcfb_pan_display,
.fb_ioctl = mxcfb_ioctl,
.fb_mmap = mxcfb_mmap,
.fb_fillrect = cfb_fillrect,
.fb_copyarea = cfb_copyarea,
.fb_imageblit = cfb_imageblit,
.fb_blank = mxcfb_blank,
};
fb_ioctl 看看有哪些现成的cmd
/*
* Function to handle custom ioctls for MXC framebuffer.
*
* @param inode inode struct
*
* @param file file struct
*
* @param cmd Ioctl command to handle
*
* @param arg User pointer to command arguments
*
* @param fbi framebuffer information pointer
*/
static int mxcfb_ioctl(struct fb_info *fbi, unsigned int cmd, unsigned long arg) //上层调用的时候就会把fbi也就是/dev/fb0之类的参数传入，
arg是要写入的数据的首地址
{int retval = 0;int __user *argp = (void __user *)arg;struct mxcfb_info *mxc_fbi = (struct mxcfb_info *)fbi->par;//fbi是linux通用标准结构体，但是不同的ic需要自己特定的framebuffer结构体
//add by matthew_xuan int matt_bpp=0; int matt_res[2]=0; // struct fb_var_screeninfo *matt_var=fbi->var;//switch (cmd) {case MXCFB_SET_LOC_ALPHA:{struct mxcfb_loc_alpha la;if (copy_from_user(&la, (void *)arg, sizeof(la))) { //获取传入的设置数据retval = -EFAULT;break;}if (ipu_disp_set_global_alpha(mxc_fbi->ipu, mxc_fbi->ipu_ch,
//这个ipu：整个IPU挂接在AXI与AHB总线上面，通过总线，它可以与ARM，VPU，GPU和RAM等模块通信。
//通过LDB控制到LVDS屏，直接控制LCD屏，并且可以通过HDMI或者MIPI来显示。
!(bool)la.enable, 0)) {
retval = -EINVAL;
break;
}
if (la.enable && !la.alpha_in_pixel) {
struct fb_info *fbi_tmp;
ipu_channel_t ipu_ch;
mxc_fbi->alpha_chan_en = true;
if (mxc_fbi->ipu_ch == MEM_FG_SYNC)
ipu_ch = MEM_BG_SYNC;
else if (mxc_fbi->ipu_ch == MEM_BG_SYNC)
ipu_ch = MEM_FG_SYNC;
else {
retval = -EINVAL;
break;
}
fbi_tmp = found_registered_fb(ipu_ch, mxc_fbi->ipu_id);
if (fbi_tmp)
((struct mxcfb_info *)(fbi_tmp->par))->alpha_chan_en = false;
} else
mxc_fbi->alpha_chan_en = false;
fbi->var.activate = (fbi->var.activate & ~FB_ACTIVATE_MASK) |
FB_ACTIVATE_NOW | FB_ACTIVATE_FORCE;
mxcfb_set_par(fbi); //这里把新设置的fbi参数传给notifier去处理
la.alpha_phy_addr0 = mxc_fbi->alpha_phy_addr0;
la.alpha_phy_addr1 = mxc_fbi->alpha_phy_addr1;
if (copy_to_user((void *)arg, &la, sizeof(la))) {
retval = -EFAULT;
break;
}
if (la.enable)
dev_dbg(fbi->device,
"Enable DP local alpha for %s\n",
fbi->fix.id);
break;
}
case MXCFB_GET_FB_BLANK:
{
struct mxcfb_info *mxc_fbi =
(struct mxcfb_info *)fbi->par;
if (put_user(mxc_fbi->cur_blank, argp))
return -EFAULT;
break;
}
case MXCFB_SET_DIFMT:
{
struct mxcfb_info *mxc_fbi =
(struct mxcfb_info *)fbi->par;
if (get_user(mxc_fbi->ipu_di_pix_fmt, argp))
return -EFAULT;
break;
}
//add by matthew_xuan
case MXCFB_SET_XRES_YRES:
{
if (copy_from_user(&matt_res, (void *)arg, sizeof(matt_res))) {
retval = -EFAULT;
break;
}
fbi->var->xres=matt_res[0];
fbi->var->yres=matt_res[1];
mxcfb_set_par(fbi);
}
default:
retval = -EINVAL;
}
return retval;
}
这里的
#define MXCFB_CSC_UPDATE _IOW('F', 0x2D, struct mxcfb_csc_matrix)
//add by matthew_xuan
#define MXCFB_SET_XRES_YRES _IOW('F', 0x2E, int struct mxcfb_matt_res)
可以参考这篇文章 http://blog.chinaunix.net/uid-20754793-id-177774.html
接下来看
static int mxcfb_set_par(struct fb_info *fbi)
{
mxcfb_set_fix(fbi);设置了fix结构体
_setup_disp_channel1(fbi); 重新定义输出屏幕的格式
_setup_disp_channel1(fbi);这里启动之后，上层应用调用输出才会成功
}
再看看
static int _setup_disp_channel2(struct fb_info *fbi)
{
retval = ipu_init_channel_buffer(mxc_fbi->ipu,
mxc_fbi->ipu_ch, IPU_INPUT_BUFFER,
fbi_to_pixfmt(fbi),
fbi->var.xres, fbi->var.yres,
fb_stride,
fbi->var.rotate,
base,
base,
fbi->var.accel_flags &
FB_ACCEL_DOUBLE_FLAG ? 0 : base,
0, 0);
}
整个大概的过程就是这样哦