9.1.2. CTP调试配置
9.1.2.1. 概述
相比RTP电阻触摸屏， CTP电容触摸屏的调试稍微繁琐一点，CTP驱动一般由触摸屏原厂提供，经过移植添加到SDK中编译和使用 本章节以GT911为例来说明一款新的CTP的调试和移植过程。
9.1.2.2. 内核配置
9.1.2.2.1. 驱动移植
驱动存放路径：linux-5.10/drivers/input/touchscreen/gt911
其中linux-5.10/drivers/input/touchscreen/Makefile修改添加如下：
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 75924acd8..4be057598 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -116,3 +116,6 @@ obj-$(CONFIG_TOUCHSCREEN_ROHM_BU21023) += rohm_bu21023.o
obj-$(CONFIG_TOUCHSCREEN_RASPBERRYPI_FW) += raspberrypi-ts.o
obj-$(CONFIG_TOUCHSCREEN_IQS5XX) += iqs5xx.o
obj-$(CONFIG_TOUCHSCREEN_ZINITIX) += zinitix.o
+obj-$(CONFIG_INPUT_TOUCHSCREEN) += gt911/
其中linux-5.10/drivers/input/touchscreen/Kconfig修改添加如下：
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index a8d18a679..6acdc3b63 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -1344,5 +1344,7 @@ config TOUCHSCREEN_ZINITIX
To compile this driver as a module, choose M here: the
module will be called zinitix.
-
+source "drivers/input/touchscreen/gt911/Kconfig"
注意
请从触摸屏供应商处获取和内核版本匹配的驱动程序，如果版本不匹配则可能编译出错，需要自行适配。
9.1.2.2.2. 内核配置
参考快速入门 - 编译概述 - Kernel配置，进入kernel的功能配置，按如下选择：
Linux
Device Drivers
Input device support
[*] Touchscreens
<M> gt911 based touchscreens
驱动以ko的方式编译后，系统启动后在启动脚本S10mdev自动加载，如下：
start() {
echo -n "Starting $DAEMON... "
start-stop-daemon -S -b -m -p $PIDFILE -x /sbin/mdev -- -df
[ $? -eq 0 ] && echo "OK" || echo "ERROR"
# coldplug modules
find /sys/ -name modalias -print0 | \
xargs -0 sort -u | \
tr '\n' '\0' | \
xargs -0 modprobe -abq
}
小技巧
如果不需要自动加载，可注释掉所示代码，仿照其他启动服务自定义加载服务。
9.1.2.3. DTS参数配置
xxx-board.dts中要添加的参数选项需要查看驱动代码中所要解析的dts参数而添加，示例如下：
GT911驱动程序中所要解析的dts参数
int input_sensor_startup(enum input_sensor_type *ctp_type)
{
int ret = -1;
struct ctp_config_info *data = container_of(ctp_type, struct ctp_config_info, input_type);
struct device_node *np = NULL;
np = of_find_node_by_name(NULL, "ctp");
if (!np)
{
pr_err("ERROR! get ctp_para failed, func:%s, line:%d\n", __func__, __LINE__);
goto devicetree_get_item_err;
}
if (!of_device_is_available(np))
{
pr_err("%s: ctp is not used\n", __func__);
goto devicetree_get_item_err;
}
else
data->ctp_used = 1;
ret = of_property_read_u32(np, "ctp_twi_id", &data->twi_id);
if (ret)
{
pr_err("get twi_id is fail, %d\n", ret);
goto devicetree_get_item_err;
}
printk("ctp_twi_id is %d\r\n", data->twi_id);
data->wakeup_gpio = of_get_named_gpio(np, "ctp_wakeup", 0);
printk("wavkeup_gpio %d\r\n", data->wakeup_gpio);
data->irq_gpio = of_get_named_gpio(np, "ctp_int_port", 0);
printk("ctp_int_port %d\r\n", data->irq_gpio);
ret = of_property_read_u32(np, "ctp_screen_max_x", &data->screen_max_x);
if (ret)
pr_err("get ctp_screen_max_x is fail, %d\n", ret);
ret = of_property_read_u32(np, "ctp_screen_max_y", &data->screen_max_y);
if (ret)
pr_err("get screen_max_y is fail, %d\n", ret);
ret = of_property_read_u32(np, "ctp_revert_x_flag", &data->revert_x_flag);
if (ret)
pr_err("get revert_x_flag is fail, %d\n", ret);
ret = of_property_read_u32(np, "ctp_revert_y_flag", &data->revert_y_flag);
if (ret)
pr_err("get revert_y_flag is fail, %d\n", ret);
ret = of_property_read_u32(np, "ctp_exchange_x_y_flag", &data->exchange_x_y_flag);
if (ret)
pr_err("get ctp_exchange_x_y_flag is fail, %d\n", ret);
ret = of_property_read_u32(np, "ctp_abs_max_x", &data->abs_max_x);
if (ret)
pr_err("get ctp_abs_max_x is fail, %d\n", ret);
ret = of_property_read_u32(np, "ctp_abs_max_y", &data->abs_max_y);
if (ret)
pr_err("get ctp_abs_max_y is fail, %d\n", ret);
ret = of_property_read_u32(np, "ctp_convert_reslution", &data->convert_reslution);
if (ret)
pr_err("get convert_reslution is fail, %d\n", ret);
printk("screen %d %d %d %d %d abs_x %d abs_y %d convert %d\r\n", data->screen_max_x, data->screen_max_y,
data->revert_x_flag, data->revert_y_flag, data->exchange_x_y_flag,
data->abs_max_x,data->abs_max_y,
data->convert_reslution);
return 0;
devicetree_get_item_err:
pr_notice("=========script_get_item_err============\n");
return ret;
}
xxx-board.dts中所添加的参数项
&twi2 {
pinctrl-names = "default";
pinctrl-0 = <&twi2_pins_a>;
status = "okay";
ctp {
reg = <0x5d>; //CTP设备地址，可以从规格书中获取
device_type = "ctp"; //默认
status = "okay"; //使能标志
ctp_twi_id = <0x2>; //所挂在的twi总线id
ctp_twi_addr = <0x5d>; //CTP设备地址，可以从规格书中获取
ctp_screen_max_x = <0x500>; //CTP x轴的范围
ctp_screen_max_y = <0x320>; //CTP y轴范围
ctp_revert_x_flag = <0x0>; //CTP x轴是否翻转
ctp_revert_y_flag = <0x0>; //CTP y轴是否翻转
ctp_exchange_x_y_flag = <0x0>; //CTP x轴和y轴是否互换
ctp_int_port = <&gpio_a 9 GPIO_ACTIVE_HIGH>; //CTP中断引脚
ctp_wakeup = <&gpio_a 8 GPIO_ACTIVE_HIGH>; //CTP reset引脚
};
};
CTP设备地址获取：
从规格书中可以看出GT911根据初始化时序的不同支持两种设备地址，默认时序的读写地址为0xBA/0xBB,读写地址去掉最后一位读写位就是设备地址，即：0x5d
硬件接线示例图如下：
注意
请务必确保dts所配置的参数和引脚与硬件原理图一致
9.1.2.4. 调试
测量硬件通路
测量硬件通路是否正常，测量电压信号是否正常
查看打印信息
在board.dts中修改bootargs，增加“loglevel=8” 调高打印级别，系统启动时或insmod驱动模块时看是否有异常打印
获取坐标信息
如果系统有编译getevent工具，触摸屏有触摸时进行坐标的打印
# getevent获取设备信息
# cat /proc/bus/input/devices 例如：（以gt9xx为例） I: Bus=0018 Vendor=dead Product=beef Version=28bb N: Name="goodix-ts" P: Phys=input/ts S: Sysfs=/devices/virtual/input/input0 U: Uniq= H: Handlers=event0 B: PROP=2 B: EV=b B: KEY=1c00 0 0 0 0 0 B: ABS=6e1800000000000