一、问题描述：
使用MTK的ATA测试工具测试LCM时提示“Not Support”
ATA是指：Assembly（安装） Test Assistant Tool
背景介绍：
一供LCD：TCL模组，IC：ILI9806E
二供LCD：BOYI模组，IC：OTM8019A
二、问题分析：
1. 我司对ATA测试LCM有过客制化，即：只要Probe成功，就立即返回Pass，所以从次入手查看，由于需要调用lcm的disp_lcm_probe函数,打印串口log来分析，从打印出来的log来看，进行测试的时候发现并未走到probe函数，即PC机和手机并未通信，此时怀疑是否有测试LCM的开关未开启，提交Eservice咨询MTK，发现果真如此，如下是MTK给出的答复：
LCM需要客制化，所以将此项注释掉了，如果需要测试此项，需要添加：
在factory.ini里面添加
MenuItem=显示屏;
/vendor/mediatek/proprietary/custom/$project$/factory/inc/cust.h
#define FEATURE_FTM_LCM
所以是测试LCM的开关未开启，导致提示Not Supprot，将开关开启进行测试，测试Pass
2. 开关开启后在测试过程中又遇到了另外的一个问题，不插入LCD进行测试的时候竟然也能测试Pass？？
由于我司只有两款LCD，所以在遍历LCD驱动只遍历两个，当都Probe失败时给默认的ili9806e的驱动；下面是抓取的拔掉LCD时的串口log：
[ 1.394421] <1>.(1)[1:swapper/0][kernel]:get_lcm_id=83.
[ 1.395068] <1>.(1)[1:swapper/0][kernel]:disp_lcm_probe ,lcm_ic_id=0x83.
[ 1.395903] <1>.(1)[1:swapper/0][kernel]:disp_lcm_probe ,lcd_id_voltage=3._lcm_count()=2
[ 1.396912] <1>.(1)[1:swapper/0][kernel]:disp_lcm_probe ,check lcd:ili9806e_dsi_vdo_tcl_blu5039.lcd_id_voltage=3.
[ 1.398192] <1>.(1)[1:swapper/0][kernel]:disp_lcm_probe ,detect lcd successfully.lcd_name=ili9806e_dsi_vdo_tcl_blu5039.
在未接入LCD时竟然能Probe成功，真是很神奇啊！
下面查看log打印所对应的代码片段：
disp_lcm_handle* disp_lcm_probe(char* plcm_name, LCM_INTERFACE_ID lcm_id)
{
DISPFUNC();
unsigned int v_i;
unsigned int lcmindex = 0;
bool isLCMFound = false;
bool isLCMInited = false;
int lcd_id0=0,lcd_id1=0,lcd_id=0;
LCM_DRIVER *lcm_drv = NULL;
LCM_PARAMS *lcm_param = NULL;
disp_lcm_handle *plcm = NULL;
//int is_need_read_ic_id=0;
//printk("[kernel]:%s,start .\n",__func__);
#ifdef GPIO_LCD_ID0_PIN
mt_set_gpio_mode(GPIO_LCD_ID0_PIN, GPIO_MODE_00);
mt_set_gpio_dir(GPIO_LCD_ID0_PIN, GPIO_DIR_IN);
mt_set_gpio_pull_select(GPIO_LCD_ID0_PIN,GPIO_PULL_UP);
mt_set_gpio_pull_enable(GPIO_LCD_ID0_PIN, GPIO_PULL_ENABLE);
mdelay(10);
lcd_id0 = mt_get_gpio_in(GPIO_LCD_ID0_PIN);
mt_set_gpio_pull_select(GPIO_LCD_ID0_PIN,GPIO_PULL_DISABLE);
#endif
#ifdef GPIO_LCD_ID1_PIN
mt_set_gpio_mode(GPIO_LCD_ID1_PIN, GPIO_MODE_00);
mt_set_gpio_dir(GPIO_LCD_ID1_PIN, GPIO_DIR_IN);
mt_set_gpio_pull_select(GPIO_LCD_ID1_PIN,GPIO_PULL_UP);
mt_set_gpio_pull_enable(GPIO_LCD_ID1_PIN, GPIO_PULL_ENABLE);
mdelay(10);
lcd_id1 = mt_get_gpio_in(GPIO_LCD_ID1_PIN);
mt_set_gpio_pull_select(GPIO_LCD_ID1_PIN,GPIO_PULL_DISABLE);
#endif
lcd_id=(lcd_id1<<1)|lcd_id0;
printk("[kernel]:%s ,lcm_ic_id=0x%x.\n",__func__,get_lcm_id());
printk("[kernel]:%s ,lcd_id_voltage=%d._lcm_count()=%d\n",__func__,lcd_id,_lcm_count());
for(v_i=0;v_i<_lcm_count();v_i++)
{
printk("[kernel]:%s ,check lcd:%s.lcd_id_voltage=%d.\n",__func__,lcm_driver_list[v_i]->name,lcm_driver_list[v_i]->lcd_id_voltage);
if(lcm_driver_list[v_i]->lcd_id_voltage == lcd_id)
{
lcm_drv = lcm_driver_list[v_i];
if(lcm_drv->get_lcd_id_register)
{
if(lcm_drv->get_lcd_id_register()== get_lcm_id())
{
printk("[kernel]:%s ,detect lcd with read ic id success.lcd_name=%s.\n",__func__,lcm_driver_list[v_i]->name);
isLCMFound = true;
}
}
else
{
isLCMFound = true;
}
if (isLCMFound)
{
lcm_kernel_detect_drv=lcm_driver_list[v_i];
isLCMInited = true;
lcmindex=v_i;
break;
}
}
}
if(isLCMFound==false)
{
lcm_drv = lcm_driver_list[0];
lcm_kernel_detect_drv=lcm_driver_list[0];
isLCMFound = false;
isLCMInited = true;
lcmindex=0;
}
if(isLCMFound == false)
{
lcd_find_success=0;
printk(KERN_ERR "[kernel]:%s ,detect lcd fail,use default.lcd_name=%s.\n",__func__,lcm_kernel_detect_drv->name);
}
else
{
lcd_find_success=1;
printk(KERN_ERR "[kernel]:%s ,detect lcd successfully.lcd_name=%s.\n",__func__,lcm_kernel_detect_drv->name);
}
plcm = kzalloc(sizeof(uint8_t*) *sizeof(disp_lcm_handle), GFP_KERNEL);
lcm_param = kzalloc(sizeof(uint8_t*) *sizeof(LCM_PARAMS), GFP_KERNEL);
if(plcm && lcm_param)
{
plcm->params = lcm_param;
plcm->drv = lcm_drv;
plcm->is_inited = isLCMInited;
plcm->index = lcmindex;
}
else
{
DISPERR("FATAL ERROR!!!kzalloc plcm and plcm->params failed\n");
goto FAIL;
}
{
plcm->drv->get_params(plcm->params);
plcm->lcm_if_id = plcm->params->lcm_if;
// below code is for lcm driver forward compatible
if(plcm->params->type == LCM_TYPE_DSI && plcm->params->lcm_if == LCM_INTERFACE_NOTDEFINED) plcm->lcm_if_id = LCM_INTERFACE_DSI0;
if(plcm->params->type == LCM_TYPE_DPI && plcm->params->lcm_if == LCM_INTERFACE_NOTDEFINED) plcm->lcm_if_id = LCM_INTERFACE_DPI0;
if(plcm->params->type == LCM_TYPE_DBI && plcm->params->lcm_if == LCM_INTERFACE_NOTDEFINED) plcm->lcm_if_id = LCM_INTERFACE_DBI0;
if((lcm_id == LCM_INTERFACE_NOTDEFINED) || lcm_id == plcm->lcm_if_id)
{
plcm->lcm_original_width = plcm->params->width;
plcm->lcm_original_height = plcm->params->height;
_dump_lcm_info(plcm);
return plcm;
}
else
{
DISPERR("the specific LCM Interface [%d] didn't define any lcm driver\n", lcm_id);
goto FAIL;
}
}
FAIL:
if(plcm) kfree(plcm);
if(lcm_param) kfree(lcm_param);
return NULL;
}
代码逻辑是通过读取GPIO口的状态来获取IC的ID;
lcd_id0 = mt_get_gpio_in(GPIO_LCD_ID0_PIN);lcd_id1 = mt_get_gpio_in(GPIO_LCD_ID1_PIN);lcd_id=(lcd_id1<<1)|lcd_id0;从log看LCD_ID=3,所以lcd_id0=1,lcd_id1=1,即从GPIO口读取的电压状态是高电平，查看ili9806e的驱动发现，ili9806e的ID默认是3，导致识别错误，下面是ili9806e的驱动注册代码：
LCM_DRIVER ili9806e_dsi_vdo_tcl_blu5039_drv =
{
.name = "ili9806e_dsi_vdo_tcl_blu5039",
.set_util_funcs = lcm_set_util_funcs,
.compare_id = lcm_compare_id,
.get_params = lcm_get_params,
.init = lcm_init,
.suspend = lcm_suspend,
.resume = lcm_resume,
.set_backlight = lcm_setbacklight_tcl,
#if defined(LCM_DSI_CMD_MODE)
.update = lcm_update,
#endif
.init_power = lcm_init_power,
.lcd_id_voltage = 3,
.lcm_ic_id = get_lcm_id,
};未插入LCD时GPIO口处于悬空状态，即高阻态，所以输出的是高电平，导致驱动识别LCD出现错误的现象；
三、问题解决方式
每个LCD IC内部还有一个IC ID，通过读取此ID进一步获知外接LCD的类型和是否存在；
现在的想法是在LK阶段获取IC ID，将IC ID写入到cmdline，启动到Kernel阶段时，一是读取GPIO获取ID，二是读取cmdline这个条件，通过获知这两个判断条件就可以区分出是哪款屏；
代码实现如下：
vendor/mediatek/proprietary/bootable/bootloader/lk/dev/lcm/ili9806e_dsi_vdo_tcl_blu5039/ili9806e_dsi_vdo_tcl_blu5039.c
增加获取IC ID的接口，并将获取到的ID写入到lcm_id变量中，方便将IC ID外传，即：
static unsigned int lcm_compare_id(void)
{
int array[4];
char buffer[3];
int id0=0;
int id1=0;
//char id2=0;
int id=0;
lcm_init_power();
mt_set_gpio_mode(GPIO_LCD_RST_PIN, 0);
mt_set_gpio_out(GPIO_LCD_RST_PIN, GPIO_OUT_ONE);
mdelay(10);;
mt_set_gpio_out(GPIO_LCD_RST_PIN, GPIO_OUT_ZERO);
MDELAY(10);
mt_set_gpio_out(GPIO_LCD_RST_PIN, GPIO_OUT_ONE);
mdelay(120);
array[0]=0x00063902;
array[1]=0x0698ffff;
array[2]=0x00000104;
dsi_set_cmdq(array, 3, 1);
MDELAY(10);
array[0]=0x00013700;//0x00023700;
dsi_set_cmdq(array, 1, 1);
read_reg_v2(0x00, &id0, 1);
array[0]=0x00013700;//0x00023700;
dsi_set_cmdq(array, 1, 1);
read_reg_v2(0x01, &id1, 1);
id = (id0<<8)|id1;
lcm_id = id;
#ifdef BUILD_LK
printf("[uboot] %s, id0 = 0x%08x, id1 = 0x%08x, id = 0x%08x\n", __func__, id0, id1, id);
#endif
if(id == ILI9806E_ID)
return 1;
else
return 0;
}
static int get_lcm_id(void)
{
return lcm_id;
}vendor/mediatek/proprietary/bootable/bootloader/lk/app/mt_boot/mt_boot.c
sprintf(cmdline_tmpbuf, "%s%s%d", CMDLINE_TMP_CONCAT_SIZE, " lcm_id=", mt_disp_get_lcm_ic_id());
cmdline_append(cmdline_tmpbuf);这样在kernel阶段会自动解析cmdline，并在里面识别lcm_id字段：
kernel-3.18/drivers/misc/mediatek/mach/mt6735/bootinfo.c
int lcm_id=0x83;
static int __init lcm_id_setup(char *str)
{
int en;
if(!get_option(&str, &en))
return 0;
lcm_id = en;
return 1;
}
int get_lcm_id(void)
{
printk("[kernel]:get_lcm_id=%x.\n",lcm_id);
return lcm_id;
}
__setup("lcm_id=", lcm_id_setup);__setup会在Kernel阶段自动解析cmdline，即lcm_id_setup()函数来解析cmdline中的“lcm_id”
备注：
有些人会问为何要在lk阶段读取寄存器，而不是在Kernel阶段，之所以这样做是因为之前有过这样做过，但是从寄存器里面读取的是空，导致读取异常，估计是Kernel阶段刚刚启动，虽然LK已经将硬件环境初始化的差不多了，但是此时软件环境还未搭建好，导致异常的发生，暂时只能从这个方面去猜测了