MTK 安卓11 lcm AVDD及AVEE值修改

通常情况下lcm的avdd默认5.4v，某些屏幕对avdd要求不同，需要进行修改

驱动程序路径：

kernel-4.14/drivers/misc/mediatek/lcm/lcm_pmic.c

int display_bias_enable(void)
{
	int ret = 0;
	int retval = 0;

	display_bias_regulator_init();

	
	ret = regulator_set_voltage(disp_bias_pos, 5800000, 5800000);//修改avdd峰值
	if (ret < 0)
		pr_info("set voltage disp_bias_pos fail, ret = %dn", ret);
	retval |= ret;

	ret = regulator_set_voltage(disp_bias_neg, 5800000, 5800000);//修改avee峰值
	if (ret < 0)
		pr_info("set voltage disp_bias_neg fail, ret = %dn", ret);
	retval |= ret;
.........

修改后效果如下：

         我们可以明显的看到，AVDD拉高后有一个阶梯，分别为5.4v和5.8v，那是因为在启动时lk里的电压设置没有修改，导致在lk中AVDD峰值为5.4v，启动后峰值为5.8v；

lk程序路径：

vendor/mediatek/proprietary/bootable/bootloader/lk/dev/lcm/lcm_pmic.c

int display_bias_enable(void)
{
    int ret = 0;
    
    ret = PMU_REG_MASK(0xB2, (0x3 << 6), (0x3 << 6));

    
    
//修改avdd 5.8v,(4v+36*0.05v)
    ret = PMU_REG_MASK(0xB3, 36, (0x3F << 0));
    if (ret < 0)
        LCM_LOGI("nt35695----tps6132----cmd=%0x--i2c write error----n", 0xB3);
    else
        LCM_LOGI("nt35695----tps6132----cmd=%0x--i2c write success----n", 0xB3);

    
    
    ret = PMU_REG_MASK(0xB4, 36, (0x3F << 0));
    if (ret < 0)
        LCM_LOGI("nt35695----tps6132----cmd=%0x--i2c write error----n", 0xB4);
    else
        LCM_LOGI("nt35695----tps6132----cmd=%0x--i2c write success----n", 0xB4);
.............

修改后效果如下：