一个硬件驱动：TI am335x系列(am3352)LCD驱动修改移植的方法
步骤如下：
- /arch/arm/mach-omap2/board-am335xevm.c/lcdc_init()
{得到LCD硬件参数struct da8xx_lcdc_platform_data} ->
am33xx_register_lcdc() ->
omap_device_build() ->
omap_device_build_ss() ->
platform_device_add_data(){pdev->dev.platform_data = d}
2、platform_device端注册过程：
omap_device_build_ss(){pdev = platform_device_alloc(pdev_name, pdev_id);} -> omap_device_register() ->
platform_device_add()
3、platform_device设备名确定过程：
am33xx_register_lcdc(){char *dev_name = "da8xx_lcdc";} ->
omap_device_build() ->
omap_device_build_ss(){pdev = platform_device_alloc(pdev_name, pdev_id);}
4、通过设备名搜索找到设备驱动文件: drivers/video/da8xx-fb.c
5、board-am335xevm.c记录的屏的类型有：
.type = "TFC_S9700RTWV35TR_01B",
.type = "NHD-4.3-ATXI#-T-1",
da8xx-fb.c记录的屏的类型有：
.name = "Sharp_LCD035Q3DG01",
.name = "Sharp_LK043T1DG01",
.name = "TFC_S9700RTWV35TR_01B",
.name = "NHD-4.3-ATXI#-T-1",
6、配置驱动程序进入fb_probe()获取LCD硬件参数用于配置struct da8xx_lcdc_platform_data：
struct da8xx_lcdc_platform_data *fb_pdata = device->
dev.platform_data;
7、匹配合适的屏，并输出屏的类型(通过dmesg查看匹配信息是否正确)，否则退出驱动:
{
if (i == ARRAY_SIZE(known_lcd_panels)) {
dev_err(&device->dev, "GLCD: No valid panel found\n");
ret = -ENODEV;
goto err_pm_runtime_disable;
} else
dev_info(&device->dev, "GLCD: Found %s panel\n",
fb_pdata->type);
}
8、fb_probe()接下来复位LCD并配置硬件参数，最后申请fb_info注册framebuffer设备
9、硬件资源设置：
am33xx_register_lcdc(){oh=omap_hwmod_lookup(oh_name);}-> omap_device_build(...struct omap_hwmod *oh,...){struct omap_hwmod *ohs[] = { oh };} ->
omap_device_build_ss(...struct omap_hwmod **ohs,...) ->
omap_device_alloc(...struct omap_hwmod **ohs,...){od->hwmods = hwmods(来至于参数ohs);} ->
omap_device_fill_resources(od, res){omap_hwmod_fill_resources(od->hwmods[i], res){填充 struct resource}} ->
platform_device_add_resources(){pdev->resource = r;}
10、资源来源omap_hwmod：
omap_hwmod_lookup(oh_name) ->
_lookup(name) ->
遍历链表omap_hwmod_list
并返回struct omap_hwmod
11、被返回的返回struct omap_hwmod来至于：
MACHINE_START ->
am33xx_init_early() ->
am33xx_hwmod_init() ->
omap_hwmod_register(){将am33xx_lcdc_hwmod添加到omap_hwmod_list链表当中}
static struct omap_hwmod am33xx_lcdc_hwmod = {
......
.slaves = am33xx_lcdc_slaves,//记录了物理起始地址
......
};
12、总结：两个数据结构共同决定LCD控制寄存器的配置参数：
static struct lcd_ctrl_config lcd_cfg = {
&disp_panel,
.ac_bias = 255,
.ac_bias_intrpt = 0,
.dma_burst_sz = 16,
.bpp = 32,
.fdd = 0x80,
.tft_alt_mode = 0,
.stn_565_mode = 0,
.mono_8bit_mode = 0,
.invert_line_clock = 1,
.invert_frm_clock = 1,
.sync_edge = 0,
.sync_ctrl = 1,
.raster_order = 0,
};
static struct da8xx_panel known_lcd_panels[] = {
[2] = {
.name = "TFC_S9700RTWV35TR_01B",
.width = 800,
.height = 480,
.hfp = 39,
.hbp = 39,
.hsw = 47,
.vfp = 13,
.vbp = 29,
.vsw = 2,
.pxl_clk = 30000000,
.invert_pxl_clk = 0,
}
}
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