【luckfox】添加压力传感器hx711

前言

本章介绍基于luckfox开发板添加压力传感器hx711，并编写测试

一、参考资料

Rockchip_RV1103_Datasheet_V1.1-20220427.pdf

二、电路图

只有这两个io口没有复用其他功能，需要关掉PWM0_0/1_0。

三、驱动

luckfox-pico-main\sysdrv\source\kernel\drivers\iio\adc\hx711.c

这里匹配gpio

static int hx711_probe(struct platform_device *pdev)
{
	/*
	 * PD_SCK stands for power down and serial clock input of HX711
	 * in the driver it is an output
	 */
	hx711_data->gpiod_pd_sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_LOW);
	if (IS_ERR(hx711_data->gpiod_pd_sck)) {
		dev_err(dev, "failed to get sck-gpiod: err=%ld\n",
					PTR_ERR(hx711_data->gpiod_pd_sck));
		return PTR_ERR(hx711_data->gpiod_pd_sck);
	}

	/*
	 * DOUT stands for serial data output of HX711
	 * for the driver it is an input
	 */
	hx711_data->gpiod_dout = devm_gpiod_get(dev, "dout", GPIOD_IN);
	if (IS_ERR(hx711_data->gpiod_dout)) {
		dev_err(dev, "failed to get dout-gpiod: err=%ld\n",
					PTR_ERR(hx711_data->gpiod_dout));
		return PTR_ERR(hx711_data->gpiod_dout);
	}

	hx711_data->reg_avdd = devm_regulator_get(dev, "avdd");
	if (IS_ERR(hx711_data->reg_avdd))
		return PTR_ERR(hx711_data->reg_avdd);
}


static struct platform_driver hx711_driver = {
	.probe		= hx711_probe,
	.remove		= hx711_remove,
	.driver		= {
		.name		= "hx711-gpio",
		.of_match_table	= of_hx711_match,
	},
};

四、makefile——添加驱动

# luckfox-pico-main\sysdrv\source\kernel\drivers\Makefile
obj-$(CONFIG_IIO)		+= iio/

# luckfox-pico-main\sysdrv\source\kernel\drivers\iio\Makefile
obj-y += adc/

# luckfox-pico-main\sysdrv\source\kernel\drivers\iio\adc\Makefile
obj-$(CONFIG_HX711) += hx711.o

配置

luckfox-pico\sysdrv\source\kernel\arch\arm\configs\luckfox_rv1106_linux_defconfig

# sensor -- hx711
CONFIG_HX711=y
CONFIG_IIO=y

五、dts——使能gpio

5.1 参考

luckfox-pico\sysdrv\source\kernel\Documentation\devicetree\bindings\iio\adc\avia-hx711.yaml

examples:
  - |
    #include 
    weight {
        compatible = "avia,hx711";
        sck-gpios = <&gpio3 10 GPIO_ACTIVE_HIGH>;
        dout-gpios = <&gpio0 7 GPIO_ACTIVE_HIGH>;
        avdd-supply = <&avdd>;
        clock-frequency = <100000>;
    };

注意，这里要改动下，需要匹配驱动中的of获取，移除gpios和supply。

//luckfox-pico-main\sysdrv\source\kernel\drivers\iio\adc\hx711.c
static const struct of_device_id of_hx711_match[] = {
	{ .compatible = "avia,hx711", },
	{},
};

5.2 改动1—— hx117节点

rv1103-luckfox-pico-ipc.dtsi
rv1103g-luckfox-pico.dts
rv1106-evb.dtsi
rv1106.dtsi
rv1103.dtsi

luckfox-pico-main\sysdrv\source\kernel\arch\arm\boot\dts\rv1103g-luckfox-pico.dts

hx711:hx711 {
	status = "okay";
	compatible = "avia,hx711"; 
	sck-gpios = <&gpio1 RK_PA2 GPIO_ACTIVE_HIGH>;
	dout-gpios = <&gpio1 RK_PA4 GPIO_ACTIVE_HIGH>;
	avdd-supply = <&vcc_3v3>;//vcc3v3_sys
	clock-frequency = <400000>;
};

dtsi中sck-gpios是全的，但是在代码中只有sck，这个是在代码中省去了，注意区分。

这里只是给hx117增加了设备节点，但是rv1103和其他平台不太一样，还需要自己在dts中定义pin的节点

5.3 改动2——引脚节点

这点真就没注意到，导致我纠结了好久，还是没有获取到hx117的数据。
参考：https://wiki.luckfox.com/zh/Luckfox-Pico/Luckfox-Pico-GPIO/

	gpio1pa2:gpio1pa2 {
		compatible = "regulator-fixed";
		pinctrl-names = "default";
		pinctrl-0 = <&gpio1_pa2>;
		regulator-name = "gpio1_pa2";
		regulator-always-on;
	};

	gpio0pa4:gpio0pa4 {
		compatible = "regulator-fixed";
		pinctrl-names = "default";
		pinctrl-0 = <&gpio0_pa4>;
		regulator-name = "gpio0_pa4";
		regulator-always-on;
	};

&pinctrl {
	gpio1-pa2 {
		gpio1_pa2:gpio1-pa2 {
			rockchip,pins =	<1 RK_PA2 RK_FUNC_GPIO &pcfg_pull_none>;
		};
	};

	gpio0-pa4 {
		gpio0_pa4:gpio0-pa4 {
			rockchip,pins =	<0 RK_PA4 RK_FUNC_GPIO &pcfg_pull_none>;
		};
	};
};

5.4 已经被定义的引脚

板子的21-27都被定义了，这是用于fspi

i2c3和spi0被enable了，需要disable后测试hx117
其中spi的cs选的是c0(28+0=16)，不是d2(38+2=26)，所以只需要关掉i2s3即可。

或者改用gpio1_A2和gpio_A4，这样不会有引脚复用，可以同时支持i2c、spi、adc。

5.5 gpio源码

都设为高电平有效GPIO_ACTIVE_HIGH

引脚作为输入还是输出由驱动中devm_gpiod_get定义

/sys/bus/iio/devices/iio:device0/

六、改动总结——使能hx711

diff --git a/sysdrv/source/kernel/arch/arm/boot/dts/rv1103g-luckfox-pico.dts b/sysdrv/source/kernel/arch/arm/boot/dts/rv1103g-luckfox-pico.dts
index 0f1a686fc..b08b1797d 100644
--- a/sysdrv/source/kernel/arch/arm/boot/dts/rv1103g-luckfox-pico.dts
+++ b/sysdrv/source/kernel/arch/arm/boot/dts/rv1103g-luckfox-pico.dts
@@ -63,6 +63,23 @@ gpio4pb1:gpio4pb1 {
                regulator-name = "gpio4_pb1";
                regulator-always-on;
        };
+
+       /* add hx711 */
+       gpio1pa2:gpio1pa2 {
+               compatible = "regulator-fixed";
+               pinctrl-names = "default";
+               pinctrl-0 = <&gpio1_pa2>;
+               regulator-name = "gpio1_pa2";
+               regulator-always-on;
+       };
+
+       gpio0pa4:gpio0pa4 {
+               compatible = "regulator-fixed";
+               pinctrl-names = "default";
+               pinctrl-0 = <&gpio0_pa4>;
+               regulator-name = "gpio0_pa4";
+               regulator-always-on;
+       };
 };
 /**********GPIO**********/
 &pinctrl {
@@ -102,6 +119,19 @@ gpio4_pb1:gpio4-pb1 {
                };
        };

+       /* add hx711*/
+       gpio1-pa2 {
+               gpio1_pa2:gpio1-pa2 {
+                       rockchip,pins = <1 RK_PA2 RK_FUNC_GPIO &pcfg_pull_none>;
+               };
+       };
+
+       gpio0-pa4 {
+               gpio0_pa4:gpio0-pa4 {
+                       rockchip,pins = <0 RK_PA4 RK_FUNC_GPIO &pcfg_pull_none>;
+               };
+       };
+
 };


@@ -178,19 +208,21 @@ &uart4 {

 /**********PWM**********/

+
 &pwm0 {
-       status = "okay";
+       status = "disabled";
        pinctrl-names = "active";
        pinctrl-0 = <&pwm0m0_pins>;
        // pinctrl-0 = <&pwm0m1_pins>;
 };
 &pwm1 {
-       status = "okay";
+       status = "disabled";
        pinctrl-names = "active";
        pinctrl-0 = <&pwm1m0_pins>;
        // pinctrl-0 = <&pwm1m1_pins>;
 };

 // &pwm2 {
 //     status = "okay";
 //     pinctrl-names = "active";
@@ -251,4 +283,15 @@ &pwm11 {



+/**********iio**********/
+/ {
+       hx711:hx711 {
+               status = "okay";
+               compatible = "avia,hx711";
+               sck-gpios = <&gpio1 RK_PA2 GPIO_ACTIVE_HIGH>;
+               dout-gpios = <&gpio0 RK_PA4 GPIO_ACTIVE_HIGH>;
+               avdd-supply = <&vcc_3v3>;//vcc3v3_sys
+               clock-frequency = <400000>;
+       };
+};

diff --git a/sysdrv/source/kernel/arch/arm/configs/luckfox_rv1106_linux_defconfig b/sysdrv/source/kernel/arch/arm/configs/luckfox_rv1106_linux_defconfig
index 4c54b6965..28a2caf94 100755
--- a/sysdrv/source/kernel/arch/arm/configs/luckfox_rv1106_linux_defconfig
+++ b/sysdrv/source/kernel/arch/arm/configs/luckfox_rv1106_linux_defconfig
@@ -320,3 +320,7 @@ CONFIG_DEBUG_FS=y
 # CONFIG_SCHED_DEBUG is not set
 # CONFIG_FTRACE is not set
 # CONFIG_RUNTIME_TESTING_MENU is not set
+
+# sensor -- hx711
+CONFIG_HX711=y
+CONFIG_IIO=y

七、验证驱动添加

可以看到驱动正常加载了，注意dmesg中的hx711相关log是我自己在驱动中添加的，默认是没有的，可以直接获取iio属性判断驱动有没有添加成功。

root@Rockchip:/# dmesg | grep hx711
[    0.091066] hx711-gpio hx711: hx711_probe
[    0.091420] hx711-gpio hx711: ret=3300000
[    0.091447] hx711-gpio hx711: ret=330000000
[    0.091456] hx711-gpio hx711: ret=1536
[    0.091464] hx711-gpio hx711: ret=6145
[    0.091471] hx711-gpio hx711: ret=3072
root@Rockchip:/# cd /sys/bus/iio/devices/iio:device0
root@Rockchip:/sys/bus/iio/devices/iio:device0# ls
of_node                      in_voltage0_raw
name                         buffer
uevent                       dev
in_voltage_scale             power
current_timestamp_clock      subsystem
trigger                      in_voltage1_scale_available
in_voltage1_raw              scan_elements
in_voltage0_scale_available
root@Rockchip:/sys/bus/iio/devices/iio:device0# cat name
hx711
root@Rockchip:/sys/bus/iio/devices/iio:device0# cat in_voltage0_raw
7949573
root@Rockchip:/sys/bus/iio/devices/iio:device0#

八、编写测试文件

应用实例ko
https://wiki.luckfox.com/zh/Luckfox-Pico/Core3566-SDK

执行文件bin
https://wiki.luckfox.com/zh/Luckfox-Pico/Luckfox-Pico-GPIO

8.1 测试代码

hx711_app.c

#include 
#include 
#include 
#include 
// #include 
#include 
#include 

#define IIO_DEVICE "/sys/bus/iio/devices/iio:device0"
#define SENSOR_CALI_PATH_OFFSET "/root/hx711_cal_offset"
#define SENSOR_CALI_PATH_SCALE "/root/hx711_cal_scale"

static int cal_offset = 8500000;    // save raw value without test items

static int cal_scale = 475;         // when set phone, 1g is 475
static int cal_weight = 187;  // the weight of phone

// static float weight = 0;
static int weight = 0;
// float convert_to_weight(int sensor_data) {
int convert_to_weight(int sensor_data) {
    int weight;
    // weight = (float)(sensor_data - cal_offset) / cal_scale;

    // printf("\nsensor_raw=%d,cal_offset=%d,cal_scale=%d\n",sensor_data,cal_offset,cal_scale);
    if(cal_scale != 0)
        weight = (sensor_data - cal_offset) / cal_scale;
    else
        weight = 0;

    // printf("Sensor data: %.1f\n", weight);
    // printf("Sensor data: %d\n", weight);

    return weight;
}


int get_hx711_raw(){
    int fd;
    char buf[64];
    ssize_t num_read;

    fd = open(IIO_DEVICE "/in_voltage0_raw", O_RDONLY);
    if (fd < 0) {
        perror("Failed to open iio device");
        return 1;
    }

    num_read = read(fd, buf, sizeof(buf) - 1);
    if (num_read < 0) {
        perror("Failed to read sensor data");
        close(fd);
        return 1;
    }
 
    close(fd);
 
    buf[num_read] = '\0';
    int sensor_data = atoi(buf);
    // printf("  raw sensor_data=%d\n",sensor_data);

    return sensor_data;
}

// float get_hx711_value(){
int get_hx711_value(){

    int sensor_data = get_hx711_raw();

    weight = convert_to_weight(sensor_data);

    return weight;
}

// save scale&offset to file 
void set_cal_value(){
    int fd;
    char tmp_char[64];

    fd = open(SENSOR_CALI_PATH_OFFSET, O_CREAT|O_RDWR ,0777);
    if (fd < 0) {
        perror("Failed to open cal offset.");
        return;
    }
 
    // printf("-------\ncal_offset=%d\n",cal_offset);
    memset(tmp_char,0,sizeof(tmp_char));
    sprintf(tmp_char,"%d\0",cal_offset);
    // printf("xxx tmp_char=[%s]\n",tmp_char);
    write(fd, tmp_char, sizeof(tmp_char));

    close(fd);

    fd = open(SENSOR_CALI_PATH_SCALE, O_CREAT|O_RDWR ,0777);
    if (fd < 0) {
        perror("Failed to open cal offset.");
        return;
    }

    // printf("cal_scale=%d\n",cal_scale);
    memset(tmp_char,0,sizeof(tmp_char));
    sprintf(tmp_char,"%d\0",cal_scale) ;
    // printf("xxx tmp_char=[%s]\n-------\n",tmp_char);
 
    write(fd, tmp_char, sizeof(tmp_char)-1);
    close(fd);
}

void print_cal_value_and_raw(int sensor_raw_tmp){
    printf("cal&raw:\n");
    printf("   cal_offset=%d sensor_raw=%d\n", cal_offset, sensor_raw_tmp);
    printf("   test_offset\t%d\n   cal_weight\t%d\n   cal_scale\t%d\n",
            sensor_raw_tmp - cal_offset, cal_weight, cal_scale);
    printf("\n");
}

void print_cal_value(){
    printf("hx711 calibration value\n");
    printf("   cal_offset\t%d\n   cal_weight\t%d\n   cal_scale\t%d\n",
            cal_offset, cal_weight, cal_scale);
    printf("\n");
}

void sns_calibration(){
    int cal_test_num = 10;
    int cal_average = 0;
    int cal_test_tmp = 0;
    int cal_scale_raw = 0;

    // test 10 times to get offset average
    for(int i=0; i<cal_test_num; i++){
        cal_test_tmp = get_hx711_raw();
        usleep(10);
        cal_average = (cal_average * i + cal_test_tmp)/(i+1);
    }

    cal_offset=cal_average;

    usleep(20);

    printf("!!! Please put test items on the board whose weight same with cmd3\nWaiting input char to continue ...\n");
    getchar();

    cal_test_tmp = get_hx711_raw();
    cal_scale_raw = cal_test_tmp - cal_offset;
    cal_scale = (cal_scale_raw)/cal_weight;

    print_cal_value_and_raw(cal_test_tmp);

    set_cal_value();
}


void get_cal_value(){
    int tmp_offset;
    int tmp_scale;
    char tmp_file_value[64];
    int fd;

    // printf("get_cal_value\n");

    fd = open(SENSOR_CALI_PATH_OFFSET, O_RDWR,0777);
    if (fd < 0) {
        perror("Failed to open cal offset.");
        return;
    }

    read(fd, tmp_file_value, sizeof(tmp_file_value) - 1);
    // printf("tmp_file_value=%s\n",tmp_file_value);
    tmp_offset = atoi(tmp_file_value);
    // printf("tmp_offset=%d\n",tmp_offset);
 
    close(fd);

    fd = open(SENSOR_CALI_PATH_SCALE, O_RDWR,0777);
    if (fd < 0) {
        perror("Failed to open cal offset.");
        return;
    }
 
    memset(tmp_file_value,0,sizeof(tmp_file_value));
    read(fd, tmp_file_value, sizeof(tmp_file_value) - 1);
    tmp_scale = atoi(tmp_file_value);
    // printf("tmp_offset=%d\n",tmp_scale);
 
    close(fd);

    cal_offset = tmp_offset;
    cal_scale = tmp_scale;


}

int main(int argc, char *argv[]) {

    char cmd1[16];
    char cmd2[16];
    char cmd3[16];
    int ret;
    int val_tmp=0;

    // calibration: put the items whose weight is known. weight sends to cmd3
    // ./hx771_app -c 187
    if(argc == 3){
        strcpy(cmd2,argv[1]);
        strcpy(cmd3,argv[2]);
        printf("cmd2=%s cmd3=%s\n",cmd2,cmd3);
        if(strcmp(cmd2, "-c") == 0){
            printf("get cal cal_weight %s\n",cmd3);
            cal_weight=atoi(cmd3);        // save the weight of cal items
        } else {
            printf("hx711 no cal_weight\n");
            return 0;
        }

        sns_calibration();

		sleep(1);

        // test the calibration result
        val_tmp = get_hx711_value();
        printf("sensor value: %d\n", val_tmp);

		return 0;
    }

    printf("-------------test-------------\n");

    get_cal_value();
    print_cal_value();

    int sensor_data;
    int test_num=5;
    while(test_num--){
        val_tmp = get_hx711_value();
        printf("%02d: %d\n",5 - test_num,val_tmp);
        sleep(1);
    }

    printf("--------------------------\n");

    return 0;
}

8.2 配置编译环境变量

需要在ubuntu环境下运行。

export PATH=/home/luckfox/Luckfox-Pico/luckfox-pico/tools/linux/toolchain/arm-rockchip830-linux-uclibcgnueabihf/bin:$PATH
source ~/.bashrc  
cd ~/luckfox/luckfox-pico/project/app/test_app/hx711
arm-rockchip830-linux-uclibcgnueabihf-gcc hx711_app.c -o hx711_app

九、验证

由于将虚拟机中生成的可执行文件复制到windows本地，再通过adb传入设备中，这部分流程比较重复，所以编写了一个简单的bat脚本进行刷入，需要输入虚拟机的登录密钥就可以执行了。

scp [email protected]:/home/youkai/luckfox/luckfox-pico/project/app/test_app/hx711/hx711_app .

adb push hx711_app /root/

adb shell "chmod 777 /root/hx711_app"
adb shell "./root/hx711_app -c 187"

直接运行这个bat脚本，然后输入密码就可以实现自动刷执行文件并校准。

刷完执行文件后也可以手动下命令进行测试。

root@Rockchip:/root# ./hx711_app -c 187
root@Rockchip:/root# ./hx711_app

十、其他——添加文件路径

busybox vi /etc/profile

'# ' --> '$USER@$HOSTNAME:$PWD# '

source /etc/profile

小结

本章实现了hx711的数据读取，以及计算出称量物品的重量，后续可以结合算法实现相关功能。