目前有一个LCD驱动，里面的LCD时序参数是：

lcd_hbp             = <40>;
lcd_ht              = <820>;
lcd_hspw            = <20>;
lcd_vbp             = <16>;
lcd_vt              = <1320>;
lcd_vspw            = <8>;

然后能正常进入U-Boot，但是新屏幕，我修改了如下参数：

lcd_hbp             = <20>;
lcd_ht              = <654>;
lcd_hspw            = <32>;
lcd_vbp             = <12>;
lcd_vt              = <828>;
lcd_vspw            = <4>;

然后就发现U-Boot进不去了，然后我适当增大了lcd_hbp、lcd_vbp的值，然后就能进入U-Boot了，修改后的参数是：

lcd_hbp             = <40>;
lcd_ht              = <684>;
lcd_hspw            = <32>;
lcd_vbp             = <16>;
lcd_vt              = <888>;
lcd_vspw            = <4>;

所以我现在的疑问是LCD时序参数里面lcd_hbp与lcd_vbp是不是有一个最小值限制呀？另外屏厂给的推荐参数就是那个不能进入U-Boot的参数值，适当增大之后对屏幕驱动是不是有相关影响呀？求各位大佬帮帮忙

@whycan 可以了，谢谢

我自己搭了个ubuntu18.04的虚拟机，打算编译A133的Longan源码，然后报了如下的错误

INFO: build arisc
make: Entering directory '/home/ceoifung/workspace/a133/longan/brandy/arisc'
arisc defconfig: generate ar100s/.config by sun50iw10p1_axp803_defconfig
#
# configuration written to .config
#
  CHK     include/generated/conf.h
  CC       driver/intc/intc.o
/bin/sh: 1: or32-elf-gcc: not found
mv: cannot stat 'driver/intc/.intc.o.tmp': No such file or directory
scripts/Makefile.build:103: recipe for target 'driver/intc/intc.o' failed
make[3]: *** [driver/intc/intc.o] Error 1
scripts/Makefile.build:146: recipe for target 'intc' failed
make[2]: *** [intc] Error 2
Makefile:91: recipe for target 'driver/obj-in.o' failed
make[1]: *** [driver/obj-in.o] Error 2
Makefile:9: recipe for target 'all' failed
make: *** [all] Error 2
make: Leaving directory '/home/ceoifung/workspace/a133/longan/brandy/arisc'
INFO: mkarisc failed

他报错说找不到 or32-elf-gcc，但是我在当前的源码目录搜了一下，是有这个工具链的，但是为什么会报错呢？

ceoifung@ceoifung:~/workspace/a133/longan$ find ./ -name  or32-elf-gcc
./brandy/arisc/coco/coco/tools/arch_toolchain/openrisc_toolchain/bin/or32-elf-gcc
./brandy/arisc/ar100s/tools/toolchain/bin/or32-elf-gcc

我是还要什么环境变量没有设置吗？我看了编译的Makefile这都是动态获取的呀，并没有相关的配置要求，求解答

@chengwei_peng kernel 4.9

@chengwei_peng 触摸驱动需要在设备树上面注册reset-gpios，查看了一下Linux设备树的reset-gpios的参数，有三个，我看一般的写法是

reset-gpios = <&pioD 22 GPIO_ACTIVE_LOW>;

但是我看了pin-ctrl.dtsi，并没有&pioD这样的写法，都是&pio PD 22这样的写法，如果我要设置PD22为reset引脚，我这样写可以吗

reset-gpios = <&pio PD 22 GPIO_ACTIVE_LOW>;

@anruliu 请问一下：屏厂给的参数就是这样的，对方FAE说这个参数可能不适用于所有的平台，需要芯片厂家推荐一个合适的值，下面是厂商给的部分参数，A133这个平台LCD的时序与这个屏幕怎么个调整比较合适呢？大佬有什么解决方法吗？

建议值：HSW=32，HBP=20，HFP=2， VSW=4，VBP=12，VFP=12
分辨率：720*800
Frame rate：60HZ

@chengwei_peng 我看到A133默认支持了FTX5x系列驱动的支持，我的驱动芯片属于atm_mxt_ts的，移植的时候，也是在这里配置是吧，只不过是一些ctp的配置没有我删减掉就好了是吗

A133的kernel里面有atmel_mxt驱动文件，有谁移植过吗

A133芯片移植触摸驱动芯片，有个twi配置

ctp {
	compatible = "allwinner,gt9xxnew_ts";
	reg = <0x5d>;
	device_type = "ctp";
	status = "okay";
	ctp_name = "gt9xxnew_ts";
	ctp_twi_id = <0x1>;
	ctp_twi_addr = <0x40>;
	ctp_screen_max_x = <720>;
	ctp_screen_max_y = <1280>;
	ctp_revert_x_flag = <0>;
	ctp_revert_y_flag = <0>;

	ctp_exchange_x_y_flag = <0x0>;
	ctp_int_port = <&pio PH 19 6 0xffffffff 0xffffffff 0>;
	ctp_wakeup = <&pio PD 22 1 0xffffffff 0xffffffff 1>; 
	ctp-supply;
	ctp_power_ldo_vol = <3300>;
};

里面的reg和ctp_twi_addr是代表什么意思呀，我的触摸驱动IC的i2c地址应该填在reg还是ctp_twi_addr呀

@anruliu 屏厂给的这个参数就是这么小的

@anruliu

lcd0: lcd0@01c0c000 {
			lcd_used            = <1>;

			lcd_driver_name     = "xiaor_amoled";
			lcd_backlight       = <255>;
			lcd_if              = <4>;

			lcd_x               = <600>;
			lcd_y               = <800>;
			lcd_width           = <190>;
			lcd_height          = <254>;
			lcd_dclk_freq       = <55>;

			lcd_pwm_used        = <0>;
			lcd_pwm_ch          = <0>;
			lcd_pwm_freq        = <5000>;
			lcd_pwm_pol         = <1>;
			lcd_pwm_max_limit   = <250>;

			lcd_hbp             = <52>;
			lcd_ht              = <654>;
			lcd_hspw            = <32>;
			lcd_vbp             = <16>;
			lcd_vt              = <828>;
			lcd_vspw            = <4>;

			lcd_frm             = <0>;
			lcd_io_phase		= <0>;
			lcd_gamma_en        = <0>;
			lcd_bright_curve_en = <0>;
			lcd_cmap_en         = <0>;
			
			deu_mode            = <0>;
			lcdgamma4iep        = <22>;
			smart_color         = <90>;

			lcd_dsi_if          = <0>;
			lcd_dsi_lane        = <4>;
			lcd_dsi_format      = <0>;
			lcd_dsi_te          = <0>;
			lcd_dsi_eotp        = <0>;

			lcd_pin_power = "eldo1";
			lcd_power = "dc1sw";
			//lcd_bl_en = <&pio PG 9 1 0 3 1>;
			lcd_gpio_0 = <&pio PB 6 1 1 3 1>;
			lcd_gpio_1 = <&pio PB 2 1 1 3 1>;
			lcd_gpio_2 = <&pio PD 20 1 1 3 1>;
			pinctrl-0 = <&dsi4lane_pins_a>;
			pinctrl-1 = <&dsi4lane_pins_b>;
		};