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如何从/dev/iio:deviceX中的LSM330读取数据?

iio android-sensors linux-kernel linux android

2

Siu Lung Leung · 技术社区 · 9 年前

&i2c1 {
    clock-frequency = <100000>;
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_i2c1_2>;
    status = "okay";

    /* LSM330 motion detector (accelerometer) */
    lsm330_accel: lsm330_accel@0x1e {
        compatible = "st,lsm330-accel";
        st,drdy-int-pin = <1>;
        reg = <0x1e>;
    };

    /* LSM330 motion detector (gyroscope) */
    lsm330_gyro: lsm330_gyro@0x6a {
        compatible = "st,lsm330-gyro";
        st,drdy-int-pin = <2>;
        reg = <0x6a>;
    };
};

该模块显示为 /dev/iio:device0 /dev/iio:device1 对于陀螺仪。他们还表现为 /sys/bus/iio/devices/iio:device0 和 /sys/bus/iio/devices/iio:device1 .我可以通过 cat in_accel_x_raw 然而,运行 cat /dev/iio:device0

在网上搜索之后,我还尝试了以下命令:

cd /sys/bus/iio/devices/iio_sysfs_trigger
echo 0 > add_trigger
cd /sys/bus/iio/devices/iio:device0
echo 1 > scan_elements/in_accel_x_en
echo 1 > scan_elements/in_accel_y_en
echo 1 > scan_elements/in_accel_z_en
echo 1 > scan_elements/in_timestamp_en
echo sysfstrig0 > trigger/current_trigger
echo 100 > buffer/length
echo 1 > buffer/enable
echo 1 > /sys/bus/iio/devices/trigger0/trigger_now

cat/dev/iio:device0 Device or resource busy cat /sys/bus/iio/devices/iio:device0/in_accel_x_raw

我对linux内核非常陌生,我的目标是将传感器数据暴露给Android系统,以便用户可以旋转屏幕等。我如何让Android从模块中获取传感器读数?

1 回复 | 直到 9 年前

1

2

Siu Lung Leung 9 年前

在查看了android logcat之后,发现android HAL没有读取或写入sysfs中目录的权限。我最后放了一堆 chmod init中的命令。rc文件,以便Android可以访问传感器数据。

# Change permissions for the LSM330 sysfs entries (accelerometer)
chmod 0666 /sys/bus/iio/devices/iio\:device0/sampling_frequency
chmod 0666 /sys/bus/iio/devices/iio\:device0/buffer/enable
chmod 0666 /sys/bus/iio/devices/iio\:device0/buffer/length
chmod 0666 /sys/bus/iio/devices/iio\:device0/trigger/current_trigger
chmod 0666 /sys/bus/iio/devices/iio\:device0/scan_elements/in_accel_x_en
chmod 0666 /sys/bus/iio/devices/iio\:device0/scan_elements/in_accel_y_en
chmod 0666 /sys/bus/iio/devices/iio\:device0/scan_elements/in_accel_z_en
chmod 0666 /sys/bus/iio/devices/iio\:device0/scan_elements/in_timestamp_en
chmod 0666 /dev/iio\:device0

希望这对别人有帮助。